The Armour Archive

Hammer dents steel, does nothing to plastic.

Try the same experiment with a whitney punch.

Small hole in metal, million shattered pieces of plastic.



------------------
Matthew Broadway (mattbroadway1974@yahoo.com)
Founder of The Armour Archive
Jack of All Trades... Master of none.

you seem to be saying that the modulus of elasticity doesn't play a significant role in fighting armor given that the tolerances are reasonably forgiving and the deformations are miniscule (1/10thish of a inch). Is this correct? If it is then the deficiency of HDPE plastic as an armoring material based on the MoE seems not to apply.

Correct. Likewise, the yeileding stress of the materails play little role in the effectiveness.

Lte me try to explain w/o breaking out any crazy mechanical analyses:

Your muscles produce a force, which incites a torque at your hand. this torque is trasnfered to the sword. (imagine, for this agruement, that you hold your arm out paralel to the ground, and keep it that way while moving). Looking at angular motion, the linear speed of the arm-sword combo is greater as you go further from the application of force. {Imagine a mouse running on a record. if he stays near the center, he will run less fast than if he runs at the edge.(because a whole circumfrence passes in one revolution. the circumfrence at 1" out is half that of 2" out)}

Ok, so you get an rotational speed of 300 rpm, and the sword point of contact is 5 foot from the source of the swing (in this simple case, your shoulder) this gives you a speed of 300 rev/min* 10*pi ft/rev * 1 min/60s
or 157 feet per second (about 105 mph).

if we assume that your sword + arm combo weighs 20 lbs, and that it comes to a complete stop (ie no bounceback at all) after 1 second, we get a force of;
F=m*a
where M is .84 slugs, and A is 157 ft/s^2
therefore f= 130 lbs

of course, stress is the measure of force/ area, so we need to figure out what type of contact area we have. (this is a simplification, we would really have to do some serious math to get a better answer). Lets say that the lenght of contact is 1 inch, and the width is .25 in. therefore the are is 1 * .25, or .25 sq in.

P=f/A, where f= 130lbf and A=.25sq in

therefore, P= 520 psi.

Lets see how this will affect a tensile specimen in the lab. (essentially, how will this stress, when applied to a sample, deform the sample downward)

the average modulus of elasticity for HDPE is: 114000 psi.
steel is: 3.0X10^6 psi.

Thus, we can use the following equation:
E=s/e, where E is the modulus, s the stress, and e the strain.
re configuring:
e=s/E
so the strain (% elongation)in the samples are:
HDPE: .0046
Steel: 1.7 X10-4 (.00017)

this is a VERY basic analysis. (i didnt get into the bending measurements, i can, if you want. ) but you see the big difference.

Now, you also realize 3 things: 520 psi is really damn far from the tensile strength of either steel or hdpe.
5230 psi is an average number for sca blows (moving the tip of your sword 105 mph is, imo kinda high, but lets be safe)
and the enlongation isnt that great.

The only issue come in, imo, is when dealing with great stresses (falling to one's knees) or where the tolerances are tight (heads) . other than that, plastic is just as safe as steel, for OUR purposes, but steel is safer in general.

-+G

Rev.: You are almost there, but you missed one equation key to this discussion. The modulus you listed is the value for a "standard" piece of the material.

The actual modulus is a function of the value you gave, the cross-sectional area, and the length of the piece undergoing the flexion. (See, e.g., http://badger.physics.wisc.edu/lab/manual/node19.html the 3rd gray box. This is for elongation, but the same formula applie to flexion).

The formula is: E=M*A/L
Where E is the modulus of the piece (as used in your equation), M is the modulus for the standard (the values you give), A is the cross-sectional area, and L is the length of the piece undergoing flexion.

Rewriting this in terms of thickness (t) and width (w) and rearanging, we get:

E=t*M*w/L

Assuming that a given piece of armor made from either steel or plastic has the same dimensions, other than thickness, we get:

E=t*M*q

where q is a constant that depends on the particular armor piece.

The thicknesses, using Dietrick's values, are:

HDPE: 3/8", 16g Steel: 3/64"

Therefore, using your values for M, the modulus is:

HDPE: 42500*q, 16g Steel: 140625*q

So plugging this in to the stress-strain formula, we get the deformation as:

HDPE: .0122/q in.
Steel: .0037/q in.

That means that for a given piece of armor, the plastic will move a little over 3 times (closer to three and a third) as much as the steel, before it springs back.

I believe this to be very significant, especially in limb protection. When the blow strikes a steel defense, the steel will flex a certain amount delivering part of the blow to that spot, and then the entire piece will move, spreading the rest of the blow over your body. The same piece made of plastic will dform three times as much, delivering more of the impact to the one spot, and spreading out less.

Consider that if your steel breastplate pushes in 1/2", you are fine, since you easily have that much cleareance between your chest and the armor. The same shape plastic plate will push in more than 1.5", which may be more than the cleareance you have, resulting in a strong punch into your chest. This is even more of a problem on the limbs, where the tolerances are less. The plastic will then spring back and look fine, whereas the steel may have a dent.

Personally, I'd rather have a dent than a broken rib.

edited for spelling and clarity

------------------
Yehuda ben Moshe
mka Juliean Galak
http://gerfalcon.tzo.com/armor/

[This message has been edited by jgalak (edited 02-27-2003).]

My experience agrees with Julian. There have ben shots I've taken to my plastic vambrace that have bruised me through it. When I was wearing splinted steel arms, I was never bruised through the steel.

Btb, Morgan I disagree with you. Say my head weights 5 lbs (I know underestimation right?)

My current helm weighs 8 lbs. Together the mass is 13 lbs (or around 6 kg)

say I get hit in the hit by around 760 Watts of power (1 horsepower, I got hit *good*) and have to dissapate it over .10 seconds. That means I'll take a force of around 7600 Newtons to the noggin. With my 6 kg helm, I'm gonna experience an acceleration of 1200 m/s^2, or basically 120 G's (told you I got hit *good*). If I was wearing a 17 lb helm, I'd have 22 lbs or 10 kgs (isn't it strange how all these examples work out to round numbers? ) Now I'm gonna only expience 760 m/s^2 or 78 g's or so.

To sum up, just over doubling the weigh of the helm caused the acceleration experienced by my brain to be reduced by 35%. And that kinda supports your "diminishing returns". On the other hand if 85 g's is enough to give me a concussion, and 78 is not, then wouldn't the doubling be a good investment?

Now in truth, all the numbers in the real impacts are much smaller. The amount of energy in the blade, not all is delivered to the target (bounce back), and the body moves and absorbs some, but its a good thought exercise.


[This message has been edited by Jean Paul de Sens (edited 02-27-2003).]

Well julian, it isnt even midterm time yet in my Mechanics of materials class.

however, the modulus you list, doesnt have the right units. A modulus of elasticity should be in units of force per unit area

the eqation you are looking at involves measure ment of force (lbs). we are dealing with stress (Psi).

remember that E=Stress/Strain
and strain= dL/L (change in length over length) and Stress= Force/area

the equation on that page deals with change in force as related to change in length.

the two equations are modifications of one another, but with real different situations.

the better way to analyze the problem is to examine the sample as a bending case.

My origiinal analysis dealt with figuring out the force, and seeing howa tensile sample would behave when subjected to that stress.

your final figures:
<i>HDPE: .0122/q in.
Steel: .0037/q in.</i>
Mine:
<b>HDPE: .0046
Steel: 1.7 X10-4 (.00017)</b>

not that your numbers are in units of inches, and mine are in strains. to convert strains to inches, multiply times original length:

.oo468X.375"=1.822 X 10^-3" (these are additional inches beyond the original length)

1.7x10^-4 X .047 = 7.99 X10^-6"

-+G




[This message has been edited by Rev. George (edited 02-27-2003).]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Rev. George:
<B>The only issue come in, imo, is when dealing with great stresses (falling to one's knees) or where the tolerances are tight (heads) . other than that, plastic is just as safe as steel, for OUR purposes, but steel is safer in general.

-+G

</B></font><HR></BLOCKQUOTE>

Nice work, Rev. I'd have phrased that last bit as "for our purposes, plastic is sufficient, but steel is safer in general." I got a lot of the same answers in early analysis, but then I started going on into more strength of material analysis. I still haven't gotten my final answers yet, but there are some problems coming up with bending that are concerning me a bit. I'd probably be better equipped to do this if I'd taken some classes in ergonomics, but I have no desire to be an IE.

Siggy

One thing to watch out for when comparing material properties: are we dealing with design properties, or actual properties.

Generally, manufacturers try to make a product that exceeds the design criteria 9x% of the time. For example, I could buy mild steel sold with a yield stress of 36 ksi. The average, actual, yield stress of such material is 37.8 ksi.

The relevance of all that depends highly on the manufacturing process. Steel is fairly consistent... enough so that insurence companies don't require yield strength testing of steel in the field before it's used. I am ignorant of any testing that takes place at the manufacturer however.

I am completely unaware of the consistency of material properties for plastics.

Rev: You are quite right, my units were off. Note, for the record, that I have never formally studied materials science. The closest I've come to this stuff is a few semesters of physics. All this was based on about 15 minutes of web searches, since I couldn't find my Machinery's Handbook.

So the important thing is this: my analysis makes it seem that you get about 3 times the displacement with HPDE that you get with steel. Your analysis (if I'm reading it right) seems to suggest that the difference is even more drastic - 228 times. Am I understanding this correctly?

If I am, then the problem is even more severe - a deflection of 1/100" in steel, which is negligible and totally safe, would result in the HDPE deflecting 2.28", a major problem, especially on the limbs. This seems too high - while my (anecdotal) experience suggests that plastic is much sprignier than steel, I don't think it's that much springier.

I maintain that in this context the springiness is a bad thing - since, as Rev. said, we are nowhere near the failure point of the materials, excessive springiness means that you are getting thwacked by your own armor.

edited for spelling and clarity

------------------
Yehuda ben Moshe
mka Juliean Galak
http://gerfalcon.tzo.com/armor/

[This message has been edited by jgalak (edited 02-27-2003).]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Broadway:
<B>Hammer dents steel, does nothing to plastic.

Try the same experiment with a whitney punch.

Small hole in metal, million shattered pieces of plastic.

</B></font><HR></BLOCKQUOTE>

I would dispute both of those points based entirely on what sort of plastic you're refering too. I've not worked with kydex at all. Both ABS and HDDP barells that I have worked with will punch fine, and I can dent them with a hammer (assuming that they sit on an anvil). I realy can't think of anything plastic that I would successfuly be able to strike with a hammer, and NOT be able to punch.

Am I the only one that is getting the impression that dietrick is just trollin for crap to post on his site to improve sales?

IMO the one thing being overlooked here. We are not in the business of re-creating star wars. we're supposed to be re-creating the middle ages....

Honestly, I think dietrick might be concerned that

Julian: Essenytially, i need to do a bending analysis. the examples we have been looking at are tensile. IE: fix a rod at the top, hang a wight to induce stress.

in those cases, a stress equivilent to a SEVERE blow (520 psi (the equivilent of over 35 atomospheres)) will only lengthen a 3/8 of an inch HDPE rod 1.82X10^-3 inches and a 3/64" steel rod 7.99 X10^-6"

Gimme some time, and let me talk to my strengths professor, and i'll have a better answer.

-+G

I come out from totally lurking to say this, You guys are scaring me away from pursuing my mechanical engineering degree. I thought if I could handle AP Physics and Calculus in highschool I would be alright, but now I doubt myself.

David
Lurker Extraordinaire

So really, you didn't disagree with me.

And doubling the helm weight eventually does something awful to your neck. Obviously diminishing return, at that point.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Jean Paul de Sens:
<B>My experience agrees with Julian. There have ben shots I've taken to my plastic vambrace that have bruised me through it. When I was wearing splinted steel arms, I was never bruised through the steel.

Btb, Morgan I disagree with you. Say my head weights 5 lbs (I know underestimation right?)

My current helm weighs 8 lbs. Together the mass is 13 lbs (or around 6 kg)

say I get hit in the hit by around 760 Watts of power (1 horsepower, I got hit *good*) and have to dissapate it over .10 seconds. That means I'll take a force of around 7600 Newtons to the noggin. With my 6 kg helm, I'm gonna experience an acceleration of 1200 m/s^2, or basically 120 G's (told you I got hit *good*). If I was wearing a 17 lb helm, I'd have 22 lbs or 10 kgs (isn't it strange how all these examples work out to round numbers? ) Now I'm gonna only expience 760 m/s^2 or 78 g's or so.

To sum up, just over doubling the weigh of the helm caused the acceleration experienced by my brain to be reduced by 35%. And that kinda supports your "diminishing returns". On the other hand if 85 g's is enough to give me a concussion, and 78 is not, then wouldn't the doubling be a good investment?

Now in truth, all the numbers in the real impacts are much smaller. The amount of energy in the blade, not all is delivered to the target (bounce back), and the body moves and absorbs some, but its a good thought exercise.


[This message has been edited by Jean Paul de Sens (edited 02-27-2003).]</B></font><HR></BLOCKQUOTE>

The question shouldn't be "safer", but "safe enough". I wear a set of LEATHER elbows, and they have protected me against direct shots that I considered excessive.

Helmets area different problem, as the weight is part of the protection. That isn't an issue for the rest of the gear.



------------------
Owen
"Death is but a doorway-
Here, let me hold that for you"

mattamus, I stand corrected.



------------------
Matthew Broadway (mattbroadway1974@yahoo.com)
Founder of The Armour Archive
Jack of All Trades... Master of none.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by flonzy:
<B>For strength I give no opinion but for heat I submit this. Wearing plastic heat builds up faster and traps itself worst than with metal. Plastic is an insulator and metal a conductor so metal is only as hot as its environment while plastic will trap and amplify heat. So in the summer plastic is far more likely to cause heat problems than metal. Plastic body armor is like wearing a thermos.

Flonzy

</B></font><HR></BLOCKQUOTE>

While I personally don't think of plastic armour being the root of all evil as some people do, I am personally trying to get into something better. These words of wisdom by Flonzy have just given me extra reason to do so. Now all I gotta do is wait for a rich relative to die and leave me their fortune

The question being addressed in this discussion is "Is Steel safer than plastic", most specifically HDPE plastic, as I believe that the documentation for ABS/Kydex failures is reasonably strong.

Although there may other issues that people want to talk about such as aesthetics revolving around the use of plastic, I'd like to remind the forum members who have chosen to post that these are not what we are trying to address. Disparaging remarks and traditional beliefs about plastic have no place here as we are trying to distill the facts of this comparison.

I'd appreciate it if we can stick to the topics. I shouldn't have allowed myself to be distracted away as well, sorry.

Now to quickly redress some commentary from some forum members.

Patrick: "The rigidity of articulation in the steel armor is part of the protection, as well. I have had knee surgery. I was out of fighting for a full year due to an SCA fighting injury. I am firmly of the opinion that a plastic leg harness would have left me with even worse problems."
and
"I use steel. Others use leather. Most of us up here avoid plastic. For safety reasons."

So Patrick is saying that he was wearing steel and needed knee surgery. He also says that "For safety reasons" most of the Alaskan fighters avoid plastic. Although that's interesting, the facts as I see them are that Patrick got injured wearing STEEL legs and that people up north have an opinion about plastic. I'm sorry, there's nothing substantial about an argument supported by OPINION.

My opinion is that placing additional weight on your body while exercising places additional weight upon your legs, thereby increasing the likelihood that you will injure your knees. This belief is JUST AS USELESS as any other opinion unless we can get proof of the concept.

There is part of Patrick's statement that raises a good discussion point: rigidity of articulation. It may play a factor, although a hard to quantify one given the wide variety of strapping options.

How would we analyze rigidity of articulation?

Vinnie:
"Well made armor is usually better than poorly made armor, regardless of material."

Hard to say no to that!

Patrick didn't like my opinion about weight and posted:
"If you strap a set of steel legs properly, they don't put strain on your knees. If you can't be bothered to strap your armor properly, let's hope the marshals bounce you during armor inspection."

I disagree. Weight on your body, is weight on your knees. Moreover the marshals are not responsible for our safety, WE ARE. They are just making sure that we comply with the rules. And there are no rules (nor any conceivable way to make them) that dictate excessively heavy armor and the long-term effects on knees. Still I will not leave my opinion about the effects of weight upon knees hanging without any support.
http://www.challenge.nm.org/archive/01-02/FinalReports/HTMLReports/091/paper.html
A report of the correlation between obesity and knee injury statistics.

http://tuftsjournal.tufts.edu/archive/2002/january/briefs/index.shtml
A Tufts Journal article discussing osteoarthritic knees which associates obesity as a risk factor

http://www.som.soton.ac.uk/research/cbcs/occuenviron.htm
University of Southampton - School of Medicine article associating a particularly high risk of knee osteoarthritis is associated with occupational kneeling and squatting, risk being particularly high in workers who are overweight

http://www.healthandage.com/Home/gm=20!gsq=weight+knee!gid2=937

Another Tufts research article comparing weight loss and exercise vs. just exercise in improving osteoarthritis in 60+ year olds.

http://www.uptodate.com/patient_info/topicpages/abstrcts/Abstrx10/2098992.htm
Framingham Knee Osteoarthritis Study (1983 to 1985): CONCLUSION: Weight loss reduces the risk for symptomatic knee osteoarthritis in women.

I could go on but this couple of links suggest that thinner people have less problems with leg function with a pretty minor degree of weight loss. I propose that similarly a pretty minor weight reduction in armor weight will also reduce the risk of knee and ankle injury, PARTICULARLY when combined with running or other similar high impact activities.

Other disparaging Patrick comments followed and don't deal with safety but rather a historical anti-plastic bias.

InsaneIrish addresses my hypocrisy of saying that I am trying to prevent eye offences and then ignore his suggestions and others suggestions.

It's a good point. I haven't done a great job of making my "armour" pretty. I should have put more effort into this and apologize for not doing so. My priorities are really tied to what my customers demand. I've sold a LOT of armor, and by in large my customers have not asked for improved historical accuracy. It therefore isn't my top priority and falls into the "I'll get around to it when I have time" category. Ultimately, it would be a good thing, and if given effective suggestions that will 1)Not reduce safety, 2)Be possible to implement given our limited production, 3)Be easy to fit via mail order and 4)Be fast enough to make so the costs will not need to increase to the customer, We’ll do it. But that's a bitch of a list and if there were easy changes that fit those criteria, why wouldn't I do them? I would. So the answer is the suggestions that I got thus far weren't a good fit for us. I didn't ignore you, I just couldn't find a way to make those changes and still run my operation with a high level of customer satisfaction. And yes, they are VERY satisfied, despite your low opinion of our product.

Irish also thinks that $230 is expensive for Blatantly non-period armor, even though he concedes that the armor offers "reasonable" protection.

His priorities are different from the hundreds of customers who have chosen us and continue to be satisfied with the protectiveness and durability of the product.

Horsefriend thinks that
1) Elasticity is bad thing for important joints.

I agree that too much elasticity would a problem. I just believe that there is room for some flex in any armor. Just about any non-brittle material used effectively will provide ample protection given good construction. There are plenty of Leather knees and elbows that are considered safe yet have MORE flex than HDPE.

2) Thick plastic could on occasion be inconvenient to body movement.

No doubt, but that's not a safety issue. If we make our gear properly (and we do) the thickness of the material has no bad effect.

3) Lightweight armor promotes field advantage above anything else.

It is only ONE of the advantages of HDPE armor. This list also includes safety (as documented by weight reduction studies above), cost (it's cheap to make and sell), and availability (we ship in under two weeks, guaranteed). If you want to bitch me out about weight, fine. But please include the number of other armories that do plastic, as well as the aircraft alum shields, plastic basket hilts. I don't make lightweight armor just to "cheat the field" of honor and strip it of historical merit. I do it for a HOST of other reasons including getting new fighters out there.

I really want to go on and address the other topics but I've got a monster of a job today picking up a 30 KW generator in Burlington, VT today for the Vermont Renaissance Festival. I am the construction manager for that cool project wherein we are building an English Tudor Village and Event site in southeastern Vermont. Too cool.

Regards,
Ld. Dieterick von Berne
Dark Victory Armory
http://darkvictory.com

Aka

Jordan Weinstein
Construction Mgr. for
The Vermont Renaissance Festival
http://vtrenfest.com

CS-Erasmus

The 2 areas I am most concerned with are the head and body. I know we don't wear plastic helms but foam liners cause the same problem. Best thing to do is get a linen coif for your head. Even with the foam the linen will help you stay cooler, cotton will not help. For body protection here are 2 cheap options:

1) http://www.valhallaleather.com/ a standard breast and back cost $72 in mild steel
2) http://www.hammeredsteel.com/gaa/armour/gaa/body.htm CoP plates cost $40 or a whole kit is $100

Again I have nothing against plastic if it is hidden but the thermos affect does concern me.


Flonzy

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Dark Victory Armory:
<B> I disagree. Weight on your body, is weight on your knees. Moreover the marshals are not responsible for our safety, WE ARE. They are just making sure that we comply with the rules. And there are no rules (nor any conceivable way to make them) that dictate excessively heavy armor and the long-term effects on knees. Still I will not leave my opinion about the effects of weight upon knees hanging without any support.
http://www.challenge.nm.org/archive/01-02/FinalReports/HTMLReports/091/paper.html
A report of the correlation between obesity and knee injury statistics.

http://tuftsjournal.tufts.edu/archive/2002/january/briefs/index.shtml
A Tufts Journal article discussing osteoarthritic knees which associates obesity as a risk factor

http://www.som.soton.ac.uk/research/cbcs/occuenviron.htm
University of Southampton - School of Medicine article associating a particularly high risk of knee osteoarthritis is associated with occupational kneeling and squatting, risk being particularly high in workers who are overweight

http://www.healthandage.com/Home/gm=20!gsq=weight+knee!gid2=937

Another Tufts research article comparing weight loss and exercise vs. just exercise in improving osteoarthritis in 60+ year olds.

http://www.uptodate.com/patient_info/topicpages/abstrcts/Abstrx10/2098992.htm
Framingham Knee Osteoarthritis Study (1983 to 1985): CONCLUSION: Weight loss reduces the risk for symptomatic knee osteoarthritis in women.</B></font><HR></BLOCKQUOTE>

I understand were your argument is coming from I just want to point out that these studies are on the ageing and overweight and power lifters. These people have day in and day out problems. Strapping armor on occasionally does not cause these effects. Also someone brought up the fact that strapping the legs correctly distributes the weight and causes less stress that is true. Even though the weight is still above the knee it won't all be balanced on the knee. Shifting the balance will help relieve stress to the knee. This goes for any armor no matter the weight. Being a weekend warrior won’t cause the effects those studies show.

Flonzy

The question does not specify whether plastic is safer than steel in an SCA context or not. Sure, maybe some plastics absorb blunt trauma nearly as efficiently as steel, but I've yet to meet the plastic (ABS, Kydex, or HDPE) that I couldn't shove a sharp sword through with minimal effort. If I tried the same thing on your average 16ga steel breastplate, I'd be lucky to get even a few centimeters of penetration.

Plastic armour sucks. Do away with it. The only reason anyone (other than perhaps Japanese personae) wear the junk is to "cheat", so to speak, at SCA combat, though I suppose exceptions ought to be made for people being required to wear armour on parts of their bodies where their personae would have worn none. People who claim some sort of back/joint/health condition that somehow prevents them from wearing real armour ought to re-think whether or not they should participate in this activity.

[This message has been edited by Joaquin (edited 02-28-2003).]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by flonzy:
<B>CS-Erasmus

The 2 areas I am most concerned with are the head and body. I know we don't wear plastic helms but foam liners cause the same problem. Best thing to do is get a linen coif for your head. Even with the foam the linen will help you stay cooler, cotton will not help...
Flonzy</B></font><HR></BLOCKQUOTE>

Synthetics are actually better here. Synthetic wicking fabrics and properly designed foam make linen look like kid stuff. Both bicyclists and motorcyclists should be able to vouch for this. The stuff you're thinking of is poorly designed and poorly executed. Of course it'll give you heat stroke.

In fact, I'd have to say that virtually all the arguments on this thread against plastic look at poorly designed and/or poorly executed amateur armour. I don't recall seeing a single argument saying sports equipment is unprotective or too hot relative to full period harness.

I'm not saying the SCA should use sports equipment. Far from it. But arguing that modern materials suck and then comparing only the suckiest of modern materials isn't exactly fair.

Paul

The basic question is "Is steel safer than plastic?" But what seems to really be asked is, "Is plastic safer that steel?"
The answer in a nutshell is yes, steel is safer than plastic. Because I would be safer wearing steel (specifically spring steel) armour from Jeff Hedgecock than a set of any plastic armour, against nearly all historical weapons. Period. Bar none.
Now then are we also asking is plastic all around better than steel? Well let's see if this breakdown is correct?

Plastic, basic points.
Pro's:
Lightweight.
Inexpensive (buyingand or/making)
Fast to produce (min of tools.)

Con's:
Not even remotely a period material(still a vaild reason given the fact that the SCA is at least supposed to be about the middle ages)
More succeptable to temperature variations then metal(in other words it has a lower meling and higher freezing point)
Is an insulator (granted one can turn it into "wiffle armour")
Cannot be used for helmets.

Steel, basic points.
Pro's:
Period material.
Is used for helmets.
Can be inexpensive.
Can be light weight.
Can look like you stepped out of a period painting.
Is historically effective against combat.
Can be made to fit you exactly.

Con's:
Can be expensive.
Can take a while to be made.
Requires more tools to make it.
Can be heavy.

The real questions that you should ask your self is what do I need my armour to do?
Does your armour protect you from the majority of weapons that you will encounter on a battlefield (regardless if it is real, SCA, or LH)?
Does your armour limit your mobility?
Does your armour limit your ability to breath?
Does your amour limit your ability to see?
Does you armour bite you?
That is what you should be yourself when constructing and/or buying your armour.
After that you should then consider price. What can you afford that still falls under the first set of questions? And while you are considering that you should always remember that this is supposed to keep you from getting mashed into a little pulp when Logan or Cuan hits you with a large wooden weapon!
After you consider what your armour should do and what it could cost and what you can afford (and the fact that Logan and Cuan are comming at you with a large weapon at high speed) then it would be a good idea to look at the visual side of your armour.
Why should you armour look remotely period and not blatantly modern? Because this is <u>all</U> about the middle ages, not monday night football. That is why. That is supposed to be the reason that draws the SCA together. That is why people prefer to wear the silly costumes in the first place. Otherwise, what is the point?
This is not about <u>you</u> ruining <u>my</u> vision of the SCA by running around in ugly ass armour. This is about you. How you are protected when you are in harm's (and Cuan and Logan's) way. How you present yourself. Why you joined the SCA in the first place.
Now after all that, if you still want to wear butt fugly armour and do not care about yourself or about those around you. That is up to you.
Me. I'm in it because it is medieval, that is why. And that is what drives me in the SCA, LH, and WMA.




------------------
"As long as there are fanatics there will always be heretics"
http://www.caerdubh.com/coeurdeleon/index.html

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Winterfell:
<B>After you consider what your armour should do and what it could cost and what you can afford (and the fact that Logan and Cuan are comming at you with a large weapon at high speed) then it would be a good idea to look at the visual side of your armour.
Why should you armour look remotely period and not blatantly modern? Because this is <u>all</U> about the middle ages, not monday night football. That is why.
</B></font><HR></BLOCKQUOTE>

This is the only part that should really matter.

Fact: The US military uses Kevlar and ceramics to stop bullets - Beats metal
Fact: The NFL uses plastic to stop linebackers – Beats metal
Fact: The SCA is none of the above.

I think this thread has big problems because it asks a question we all should be able to agree on. Deep in your heart do any of you really think period harness would be able to outperform a well-designed, completely articulated, professionally-lined modern-material rig for SCA rattan combat? Probably not. So why argue the point? Give plastic its props; it’s an awesome material and deserves to be recognized as such. But the goal for mundane items in the rest of the SCA is to hide them and the same should be true on the battlefield.

Paul

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Broadway:
<B>mattamus, I stand corrected.

</B></font><HR></BLOCKQUOTE>

Mine is not the most significant post on this thread... But you're partialy right too. Say, plex will certainly shatter with a punch... but I can't hit it with a hammer (or rattan) either. Similarly... 'denting' plastic requires a pretty stiff backing (as I said, like an anvil) worn as armor, I could never dent it even with a big sledge.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Total_Wimp:
<B>
Fact: The US military uses Kevlar and ceramics to stop bullets - Beats metal
Fact: The NFL uses plastic to stop linebackers – Beats metal
Fact: The SCA is none of the above.
</B></font><HR></BLOCKQUOTE>

We are not talking about Kevlar or the stuff used by the NFL. We're talking about (as per the first post in this thread) High-Density Polyethylene (HDPE) cut straight off the barrel and made into what Dark Victory calls "armour." Visit his site and take a look at what he's selling and charging $200 for.

We're talking about a material that has a Modulus of Elasticity that drops dramatically as the temperature goes below zero Celcius. Contrary to what Dark Victory will tell you, I HAVE seen HDPE shatter at low temperatures (approx. -15 C). Now, I have to confess that my knees and elbows have HDPE elements, because as a 13th century german, while it is possible for me to have metal knees and elbows, it isn't entirely likely. In the winter, you will often hear me say that I'm not quite ready to fight yet. When I say this I'm not ready to fight because I'm waiting for my armour to warm up.

Siggy

How would we analyze rigidity of articulation?
___________

Well, we could look at whether the joint articulation flexes in a direction it should not. For example, does it flex sideways? Articulated steel will not. Plastic that is tied together with parachute cord will. Skillful articulation (Dietrich's term, not mine) should encompass the range of motion of the joint (knee is this case) that it is meant to protect without allowing more than the knee can survive.

My knee injury was not due to weight of armor. I never implied such above. Dietrich simply decided to try to turn my reason for avoiding the plastic armor into an attempt at further sales pitch. My injury was caused by fighting on uneven ground and landing really badly, twisting the knee when I landed. Yes, the steel armor may have added about 45 pounds to the overall impact. I don't discount that. However, it is the fact that my armor of the time allowed my knee to twist in a way that it is not meant to that resulted in a torn meniscus. Flexible plastic might have taken half of the added weight off of the landing (only 28 pounds added to the fall including helm and padding, instead of 45 - a difference of 17 pounds), but I have a coworker who got the same injury slipping on the ice without any load at all. It is something that can happen when you fall and twist on the landing. The armor I rebuilt will brace my knees in such a way that it should be impossible to incur a similar injury in the future. That's not possible with bits of plastic barrel, only with metal. (I say metal because I can see aluminum or titanium doing the same job, as both can be rigid enough.)

I know that plastic weighs less than steel. If a fighter just wants a sports advantage, he should be aware that he does sacrifice some protection to get it. The result is that his gear looks crappy, but is light in weight. It doesn't need to have dents pounded out, but it will allow some flex under the impact of a stout blow that may cause bruising underneath (see posts above). It is a tradeoff.

And the argument about football gear protecting better fails to take into account that many football players sustain some serious injuries, in spite of the fact that they are trained athletes in (usually) very good physical condition. The game takes a toll on the body of the player. So does SCA, but I have seen far fewer debilitating injuries in SCA combat than in pro sports. Just my impression, I don't have statistics. If anyone can prove me wrong, I'd love to know better.

And to clarify a misinterpretation I seem to have inadvertantly given, it is in Fairbanks, not all of Alaska that people avoid plastic for safety reasons. Anchorage does not get the harsh winters we get, so there are a couple of guys who I know have experimented with plastic.

-Patrick

<I>"Fact: The US military uses Kevlar and ceramics to stop bullets - Beats metal<i>"
Actually that would be bullet resistant.
"Fact: The NFL uses plastic to stop linebackers – Beats metal"
This was answered by another person already
"Fact: The SCA is none of the above."
The SCA is a martial sport, using a minimum 1 1/4 inch thick duct taped wrapped piece of rattan, that can break an unarmoured person, hence the armour requirements in the first place. The object is not to end up crippled from playing this game.

"I think this thread has big problems because it asks a question we all should be able to agree on. "
<B>Unfortunately this is not a subject that is as easy to answer as, say, which is faster 10mb or 100mb? So welcome to the Armour Archive!<b>
"Deep in your heart do any of you really think period harness would be able to outperform a well-designed, completely articulated, professionally-lined modern-material rig for SCA rattan combat?"
<b>In a heart beat, yes. I well designed, completely articulated professionally made spring steel suit of armour such as one by Jeffery Hedgecock or Robert Mac Pherson
http://www.lightlink.com/armory/gallery.html
would, could and does out perform any modern plastic PoS armour. Bar none.</B>
"So why argue the point?"
Because. That's why. <B>
"Give plastic its props; it’s an awesome material and deserves to be recognized as such."
It is a versatile material, and has many uses, but an acceptable substitute for medieval armour is not, in my opinion, one of them.
"But the goal for mundane items in the rest of the SCA is to hide them and the same should be true on the battlefield."
<B>The goal really should be to keep the mundane items to a minimum, and if you cannot do without them, then they should at least be hidden.
I would also like to note, that it is not the material that irks me, so much as the pride some folks take in the fact that they are wearing plastic.</B>


------------------
"As long as there are fanatics there will always be heretics"
http://www.caerdubh.com/coeurdeleon/index.html

[This message has been edited by Winterfell (edited 02-28-2003).]

Commentary Batch #2


Cunian

1) Thick HDPE is clumsy and fitted armor is better.

Thick armor is protective and, yes, fitted armor is better, but it costs more and needs to be fitted to the wearer. Our customers seem to like the fit though.

2) Scooped arms make breastplates work better, but people get hit in the ribs more.

Yup, that's why we don't scoop the armholes. Plastic is easy enough for anyone to modify to their own tastes.

3) Winged HDPE knees are hard to cover.

But they are protective. Safety is our primary concern in design. I could make a more hidden knee, and it would do a worse job of protecting. Not a trade off I'm interested in making.

4) Why doesn't a nice Dieter make a COP with steel parts to go along with it?

Other people have that market covered pretty well. If I decided to enter the steel market I'd invest $10-20K, fly over to Meerut City, work out the designs, surface ship in a barge of armor and flood the munitions grade market with gear, effectively killing the domestic armories. I'm pretty sure I could make more money that way, but why would I. A lot of nice guys in the states live interesting lives working as armorers. I have the resources to do it but not the will to do that damage. I do not now, but perhaps with enough goading I might develop a mean streak.

Tristan from the Black Forest want to know if having too much plastic deformation could cause damage.

Yes, it could. Wrap yourself in cellophane and you're gonna get hurt. That's why we're discussing the relative strengths of materials.

Dagonet doesn't know anything about science but has opinions that he doesn't support with facts. That's nice.

Edwin gives a cool formula for describing the ratio of strength to thickness. He is concerned about the inability of plastic to shed heat and about the lack of mass in plastic knees.

Heat can be a concern, but can be moderated by whiffling (since we are covering it up why not. Lack of mass may indeed be an issue, but I don't know how to analyze it. Any suggestions?

Winterfell is of the opinion based upon personal experience that plastic transmits more shock than an aluminum COP or a steel breastplate.

Could be so. It could hurt more, particularly if the person is poorly padded. My own experience doesn't see much of a difference having fought steel and plastic, but I had reasonable padding in both. One thing is certain, given the flexion of plastic, padding is more important than with more rigid materials.

Flonzy think that a ball peen is specifically made to move steel and therefore a poor example case.

Okay dude. We'll use a baseball bat then. I believe that the results will be very similar.

Rev. George blows me away with the cool calculations and concludes that in "The only issue come in, imo, is when dealing with great stresses (falling to one's knees) or where the tolerances are tight (heads). other than that, plastic is just as safe as steel, for OUR purposes, but steel is safer in general. "

Which seems to be saying that the problem areas are great stresses or tight tolerance are the problems but otherwise plastic is just as safe.

You're confusing the shit out of me by saying "for OUR purposes steel is safer". WTF? Could you run through that again for me?

jgalak tweaks Rev's formulas and concludes that a steel breastplate moving in 1/2" will equate to a HDPE breastplate moving in 1 1/2" in.

Yes plastic moves more. I'm not sure how many plastic breastplates have been moved to the point of failure, but I do know that I've seen plenty of steel ones move in 1/2" and stay that way. It is conceivable that they do move 3x steel, which would explain a lot about the "sting factor" reported by others. That is the crucial reason why padding is an essential element to plastic armor. If it moves more you will need more padding to give it time to slow down. But given that effective padding is used, aren't we dealing with apples and apples?

BTW it's not necessarily 3x padding as there is a time component to the impact as the plate overall begins to move, and we haven't even begun to consider how much the elasticity difference btw HDPE and steel will rebound the weapon. Moreover aren't the calculations that you guys are using for static pressure rather than an impact? Yup. I visited that link you mentioned. It's about loading a rather than impact.

Samuel thinks I'm trolling for marketing language for my site.

Nope Sam. I was motivated to investigate this by a claim I've heard time and time again that steel is the king of beers and that plastic is dangerous to wear. When Duke Logan said that he'd blown apart 10 plastic legs I got a bit curious to see if they were mine. So I decided to take the time to find out what the essential parts of the argument against HDPE were and to address them rather than letting the Mythology that plastic sucks continue. Yeah maybe it does suck from a historical perspective, but I'm trying to see what shortcomings it has from a protection and safety perspective. Thus far, it seems to be doing ok.

flonzy doesn't mind hidden plastic but proposes two kits are good alternative.

Sure. They are kits, and take some work to assemble but they'd work fine. This has to do with steel being safer than plastic.... how?

flonzy also doesn’t' like the studies cause they talk about fat or old or weightlifter people. He concludes that the fighting will not cause these same effects in people only doing it on every weekend.

No they ALL talk about overweight people and the effects that weight has on knee injuries. I must disagree with his conclusion for two reasons:
1) The stresses of running with extra weight (particularly with people in the US who themselves have extra gut/obesity) is PRECISELY what can cause these types of problems.
2) Shifting the balance of the legs is fine but unless that weight is somehow transferred BELOW the knee, it does nothing to remove that weight from being supported by the knee.

Joaquin want to shove a sharp sword into plastic as a test of it's field worthiness. He also thinks that if you can't wear steel for health reasons that maybe you shouldn't be on the field.

Sorry bud, we don't allow live steel on the field. And that's not what we're trying to armor against. Regarding the "unhealthy" fighters, I'm glad you don't make the rules. If you get broken, and you still want to play, you shouldn't wear gear that will allow that? I don't think so.

Okay enough for now. Winterfell has such a kick ass analysis I don't have the horsepower to plow through it tonight.

Thanks guys, this discussion is getting really interesting.

Regards,
Ld. Dieterick von Berne
Dark Victory Armory
http://darkvictory.com

I didn't say I wanted to test a piece of plastic armour's (presumably SCA) "fieldworthiness" by attacking it with a sharp sword. I said that, in my experience, plastic does not perform at anywhere near the level that even mild steel does when faced with a sharp instrument. I conclude, therefore, that plastic is far inferior to steel in defensive capabilities.

Where do you get that I intended to stab something with a real wepon as a test of its SCA list-legality? Your original question asks whether or not plastic is safer than steel. You say nothing about "safer only in an SCA context". Nowhere in your initial post is there anything that made me think you meant it as an SCA-combat-specific topic.

[This message has been edited by Joaquin (edited 02-28-2003).]

Boy, I sure was wrong about getting the agreement, but I'm flabbergasted as to why.

Forget Dark Victory. Forget plastic barrels. Forget sports armour designed for mundane sports.

Think instead of armour designed to the standards of mundane sports, but designed for the specific stresses of SCA rattan combat.

Think about a *high quality* cup. You have very strong rigid plastic that doesn't shatter. You have very selective padding that keeps edges from digging into skin but adds little weight. You have well-spaced holes to provide circulation and keep weight down. You have elastic to keep it snuggly in place with minimal discomfort.

I am not arguing that cups are the most comfortable thing on the planet while able to stop a speeding bullet. I'm arguing that the design, light, snug, breathable and strong enough to withstand the specific impacts of the sport without being overbuilt, would totally kick ass over the specific, awesome armour you gave as an example. I’m also arguing that the benefits of the design in a well-built cup didn't even exist in period.

I've ridden 70-mile bike rides with the first half uphill in 90-degree weather with a helmet built to withstand crashing into pavement at 35mph and not suffered from heat stroke. Are period full-face steel helms *ever* up to those standards?

Look, the armour you gave as an example is simply awesome. For SCA combat it would be my overwhelming preference bar none. But if SCA combat were a multimillion dollar sport and endorsements worth 20 million dollars were riding on you winning and you got to pick anything you wanted, there is no way in hell you'd fight in that thing rather than something modern and lightweight. If you disagree, so be it, but I don’t think there’s any way I’ll understand why.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Winterfell:
<B> "Deep in your heart do any of you really think period harness would be able to outperform a well-designed, completely articulated, professionally-lined modern-material rig for SCA rattan combat?"
<b>In a heart beat, yes. I well designed, completely articulated professionally made spring steel suit of armour such as one by Jeffery Hedgecock or Robert Mac Pherson
http://www.lightlink.com/armory/gallery.html
would, could and does out perform any modern plastic PoS armour. Bar none.</B>
[/B]</font><HR></BLOCKQUOTE>

one thing to say DEATH BEFORE PLASTIC!

------------------
war is hell. wanna raise some hell?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Dark Victory Armory:
<B>
Flonzy think that a ball peen is specifically made to move steel and therefore a poor example case.

Okay dude. We'll use a baseball bat then. I believe that the results will be very similar.

flonzy also doesn’t' like the studies cause they talk about fat or old or weightlifter people. He concludes that the fighting will not cause these same effects in people only doing it on every weekend.

No they ALL talk about overweight people and the effects that weight has on knee injuries. I must disagree with his conclusion for two reasons:
1) The stresses of running with extra weight (particularly with people in the US who themselves have extra gut/obesity) is PRECISELY what can cause these types of problems.
2) Shifting the balance of the legs is fine but unless that weight is somehow transferred BELOW the knee, it does nothing to remove that weight from being supported by the knee.</B></font><HR></BLOCKQUOTE>

Again a baseball bat is unfair. Unlike rattan were the energy is along the length of the stick because the weight is towards the bottom a bat is shaped top heavy to transmit the energy to the top of the bat, just like a hammer. Cut the knob off the bottom of the bat and strike with the tin end and you will not get much energy. Rattan is all that matters and steel stops it as good or better than plastic depending on armor quality.

As for the knee injury studies again those people have problems because they constantly are fat or being elderly weakens the joints of weight lifter put hundreds of pounds on their knees and do the lifting multiple times a week, not the same as adding 20 to 60 pounds to you on the weekend for a few hours and sitting between rounds. These people are having constant added weight we have temp added weight. The study on weight lifters didn’t talk about doing the exercise wrong either as far as I read, and that is the one most do wrong thus causing knee injuries.

BTW I already said the weight will be there when you strap on the legs but I said if you strap them right you balance the weight and relieve pressure from the knee.

Flonzy

------------------
Cheap garb is as bad as plastic armor.
http://home.armourarchive.org/members/flonzy

[This message has been edited by flonzy (edited 03-01-2003).]

You're confusing the shit out of me by saying "for OUR purposes steel is safer". WTF? Could you run through that again for me?

Ok... you misquoted me. what i said:

The only issue come in, imo, is when dealing with great stresses (falling to one's knees) or where the tolerances are tight (heads) . other than that, plastic is just as safe as steel, for OUR purposes, but steel is safer in general.
Without the math:

The forces a particular piece of armour will be subjected to in SCA combat, (even in atlantia, J/k guys) is well below the allowable stress of a material. We get an allowable stress by dividing the critial strength(in this case yeild strength) by a factor of safety. No engineer worth his salt will design a device that directly affects a human w/o a factor of safety. 2-5 is the normal range for factors of safety. so, if we go at the high end, we want the material to be strong enought to resist stresses five times that to which it would normally be subjected.

Sca blows, are, as a general rule, far below the yield strength of either material, and extend the material less than a sixteeth of an inch.

If we were dueliing with live steel swords, that might not be the case.
If we were dueling with wasters, that might not be the case
If we used lead pipes, that might not be the case.

But for OUR purposes (SCA COMBAT) plastic is just as safe as steel, except, possibly in cases dealing with extreme forces (my 320 lb ass falling straight to my knees for example) or in low tolerance areas (minimlally padded helmets). In those cases, as well as in general, steel is safer (as it could handle the leadpipe/wasters/sharps better)

-+G

Back to the fray #3

Winterfell did a lot of work on this commentary, so I'm working with this as a base document and will make modifications interspersed begun with "DVA"


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR><font face="Verdana, Arial" size="2">Originally posted by Winterfell:
<B> {Snip }I would be safer wearing steel (specifically spring steel) armour from Jeff Hedgecock than a set of any plastic armour, against nearly all historical weapons. Period. Bar none.

DVA - Chuckle. Yes Spring Steel is superb, but you are in a whole different world when using that as your basis for comparison.
{Snip}

Plastic, basic points.
Pro's:
Lightweight.
Inexpensive (buyingand or/making)
Fast to produce (min of tools.)
DVA additions
Easy to repair (550 cord rather than rivets and straps)
Rustproof and VERY few straps and no moving rivets therefore LOW maintenance
Protective - when properly padded

Con's:
Not even remotely a period material(still a vaild reason given the fact that the SCA is at least supposed to be about the middle ages)
DVA - Not a safety issue therefore doesn't apply.
More succeptable to temperature variations then metal(in other words it has a lower meling and higher freezing point)
DVA - melting point of HDPE is 234-243 degrees F (http://www.sperecycling.org/PDF%20Files/0738.PDF)
Also the "brittleness point" is -100 degrees F. (http://www.equinesystems.com/ridgid.htm)
Therefore the argument about temperature is poppycock.
Is an insulator (granted one can turn it into "wiffle armour")
Cannot be used for helmets.
DVA - chuckle, that last one is sort of true. A helmet COULD be made to be safe, but it would be large and would need additional weight on it to be safe. Read as a chain camail, but I'm not advocating that. Too many fools would do it wrong.

Steel, basic points.
Pro's:
Period material.
DVA - not safety related.
Is used for helmets.
DVA - not safety related.
Can be inexpensive.
DVA - can be, but more often isn't
Can be light weight.
DVA - can be, but more often isn't
Can look like you stepped out of a period painting.
DVA - not safety related.
Is historically effective against combat.
DVA - has worked in the past, so has plastic.
Can be made to fit you exactly.
DVA - so can plastic

Con's:
Can be expensive.
Can take a while to be made.
Requires more tools to make it.
Can be heavy.
DVA - you missed a few
Rusts
Straps mildew, rivets break, dents, rusts.

{Snip some valid point to armor selection based on functionality}


After that you should then consider price. What can you afford that still falls under the first set of questions? And while you are considering that you should always remember that this is supposed to keep you from getting mashed into a little pulp when Logan or Cuan hits you with a large wooden weapon!

DVA - It's a good perspective that Winterfell has by choosing function first before price. Your gear has got to do what you want it to.


{Snip - paraphrase - visual appearance is important to the game we play; don't wear modern stuff, not for his sake, but for your own}

DVA - Yes, reasonable. But not safety related, unless you believe that Cuan or Logan are going to try to hurt you for wearing plastic. Not likely.

We mixed safety and other issues together here Winterfell. I propose that your other issue may have merit, but weren't we really trying to address Steel vs. HDPE plastic in terms of safety.

Regards,
Ld. Dieterick von Berne
Dark Victory Armory
http://darkvictory.com </B></font><HR></BLOCKQUOTE>

Dagonet wrote;
I don't know anything about the science, but in practical applications, plastic knees are some what less safe than metal. This point, which others have made before, is that plastic knees are simply not substantial enough to absorb some low shots. I believe the shots in question are those from great weapons, where the force generated can be significantly greater than the force from a single hand sword. The forgiving and elastic nature of plastic does not always do enough to protect the knee in those situations. The danger is amplified when the person wielding the great weapon doesn't really have control of the weapon and proceeds to knock the hell out of the knee. The fact that the leg is often planted firmly to the ground, preventing flex, and that the plastic bends, transfers the force into the joint, instead of distribuiting it through the armor. The weight and rigidity of steel does a better job of absorbing significant shots.
One cent...two cents,

Dagonet

Dark Victory Armory wrote;
Dagonet doesn't know anything about science but has opinions that he doesn't support with facts. That's nice.

Dagonet writes;

No need to be a dick bro. If you find my comments lacking of worth due to their lack of formula pulled from the net, simply ignore them. Your comment does absolutely nothing to support your arguement. The only thing it does do is to say that you hold me to be an iddiot. If that is your opinion fine, keep it to yourself unless it is relevant to the situation at hand. If you need filler for your posts, try looking on some more web pages for knowledge to use.

Dagonet