Historical cuir bouilli weight and hardness

[Buster]

I'm not expecting anyone to have a clear answer here, but do we have any idea of the thickness and/or hardness of historical cuir bouilli?
http://www.flickr.com/photos/roelipilami/6840030630/
This page lists both the dimensions and weight for the 14th century rerebrace in the British museum, but unfortunately not the thickness. (Though I am surprised by how long it is, evidently it was the full length version common in England.)
Would it be of any use to use it's dimensions and weight to calculate an approximate average thickness, or would it's age have made this pointless? It seems to be around 11 inches long and 8 ounces as is, and is obviously not a full square, so it may have actually been quite thick, especially if it was heavier when new.
As for it's hardness, it appears to have some hard shape to it, while at the same time it has been flattened without visible damage. I'm unfamiliar with reproduction cuir bouilli, could any of this be taken as evidence of it's original hardness?
(Interestingly, even this rerebrace has those strap slots that were so common in the 14th century.)

[Gerhard von Liebau]

Before I started making my own reproduction leather armor I was able to play with multiple pieces made by Dan Houchins (of House of the Wolf). He did some pretty nice cuir work in the fourteenth century style and even made a rather flash reproduction of the BM rerebrace. Typically Dan liked to use 13-15 oz leather for his armor, and I understand why. The thicker the leather is, the easier it is to get it to hold it's shape while wet and the less likely it is to be crispy-fried during the heating process. For SCA combat, well-hardened leather armor of that thickness is almost impossible to even feel solid blows through, much less mess up the armor. I even stabbed the corner of one of my pieces once with a dagger and hardly got it to penetrate.

Since then the few pieces I've made have been in imitation of Dan's style, and use similar thickness and hardening process. That involves wetting the leather thoroughly, shaping it, air drying it until it's not floppy and then doing a quick jaunt in the oven to suck the remaining moisture out of the leather as thoroughly as possible before it starts to get scorched. The product is extremely durable and maintains it's shape (even complex) very well. Think saddle horn stiff.

Now, most modern cuir is probably not made at all like the original stuff, which included a complex and still rather mysterious process of dipping in boiling water, allowing it to cool in open air and over a fire, and possibly even repeat procedures. I've seen at least one period source describing the process (in Middle English, I do think) and it's definitely been posted about here on the Archive. I'm just waking up and my coffee is only a few sips down... So I'm going to stop typing now and get back to that. Someone else can finish the story.

-Gerhard

[Mac]

Buster,

You got a good start going there. Make up a template to the dimensions and shape of the original, and then figure out how many square inches it covers.

Does anyone here know the history of this object? If it has always been in relatively normal conditions, (as opposed to an excavated atifact) It should be about the same size and weight as it always was.

Mac

[Mac]

Here is a small picture of the object from the British Museum's 1924 "Guide to the Mediaeval Antiquities and Objects of Later Date". It is a detail of fig. 182 p. 273.

Although the pic is small, it is taken from directly above the object and there is no distortion or foreshortening.



Mac

[Mac]

Here is what I came up with for a shape. I filled in the missing bit in the corner, but did not count it in the area calculations.



The current area is about 79.92 square inches, or .548 square feet.
If the weight is 228g or 8.04 oz., and the object is .548 square feet, then if the object were 1 square foot, (8.04 divided by .548) it would weigh. 14.67oz. That is to say, that by first approximation, it was made of "14.67oz. leather".

Math is not my strong suit. I am confident that my reconstruction is good, and that the square footage is pretty close, but 14.67 oz leather seems heavy to me.

Incidentally, the asymmetry of the object shows that it is without a doubt a "right" and that the holes were at the shoulder. The rerebrace is too long for my arm, but that does not surprise me. I think It would fit a person of normal proportions and a height of about 5'10".

Mac

[Kilkenny]

Mac,
From my experience working with hardening leather, I think that sounds like it is right down the pipe of what I would expect it to be. I routinely work in leather that runs 13-15 ounce (heavy "saddle skirting").

This leather hardens reliably and without becoming brittle, whereas my experience with lighter leather suggests it is difficult to reliably harden by the methods I have used without it becoming brittle and shrinking excessively.

Personal correspondence with one of our archive denizens has made me aware of another surviving example of a leather leg harness that would appear to be made of quarter inch or heavier leather (and painted to resemble steel...).

[Russ Mitchell]

Quarter-inch thickness is pretty serious, and would explain some of the seemingly VERY long tan times you see cited for pit-tanned Italian vegtan. Or, they were eating a lot of draft horse. O.O

[Mac]

Mac,
From my experience working with hardening leather, I think that sounds like it is right down the pipe of what I would expect it to be. I routinely work in leather that runs 13-15 ounce (heavy "saddle skirting").

Gavin,

But, does my math seem sound? I am pleased to accept whatever thickness it turns out to be. I just hope someone will run a reality check on my math.

Personal correspondence with one of our archive denizens has made me aware of another surviving example of a leather leg harness that would appear to be made of quarter inch or heavier leather (and painted to resemble steel...).

Can you tell us more about that?

Mac

[Buster]

Mac, thanks for doing that, your shape and calculations seem spot-on. 14 ounce leather is much thicker than I was expecting, especially since this rerebrace was probably worn over mail.
Hardened leather that thick would probably have been a pretty balanced alternative to metal armor.
In light of what Gerhard and Kilkenny said, the thickness would also make sense from a construction standpoint. My own limited experience with hardening leather has been with much thinner leather (~6 oz.), and I've always been frustrated with how crispy looking it gets.

[Russ Mitchell]

Yeah, the math looks good. I can make a pretty thin half-tanned armor piece, but that's mostly the inner rawhide talking. To really harden straight veg-tan, the thicker pieces always seem to harden much better.

[Mac]

your shape and calculations seem spot-on.

Yeah, the math looks good. .

.

Thank you, guys! I would not want my conclusions to be accepted without someone running a reality check on my math.

Mac

[Kel Rekuta]

My only question in these calculations would be how much weight is the glycol/wax stabilizer in the piece, if such preservation has been done?

I craned my neck around from every angle I could manage in front of the display case that thing is in at the BM. I would be very surprised to learn it was 14oz veg back in the day. Maybe there is some further detail on the British Museum website? Or in Leather and the Warrior? I don't have access to that book at the moment.

[Mac]

My only question in these calculations would be how much weight is the glycol/wax stabilizer in the piece, if such preservation has been done?

I craned my neck around from every angle I could manage in front of the display case that thing is in at the BM. I would be very surprised to learn it was 14oz veg back in the day. Maybe there is some further detail on the British Museum website? Or in Leather and the Warrior? I don't have access to that book at the moment.

Kel,

There is also the question of whether, and how much, the object may have shrunk. If it has always been more or less dry, this may not be much of an issue, but it came out of the ground, the shrinkage is likely to have been significant.

Mac

[RandallMoffett]

I do not think this has likely been in the ground. It was floating around collections in the early 19th century until Charles Roach Smith bought it then later sold to to the British Museum, 1850s. So likely was in some private home or armoury and found when these old items became in high demand. Seems very little has been done to it as far as treatments that would alter the weight.

My guess is it likely went pretty much from the point of the shoulder to the elbow at 11 inches. I am not sure it is quite 14oz but it was thick. I was able to get a fairly good look but not allowed pictures.....

Having looked at some of the only leather armours from the period I'd love to know what they did to it. I sort of wonder how hard it was made at the time as with time leather untreated and then kept so gets drier and hard. Time machine maybe would help. Needless to say much of the armour I have seen still has flex and though often brittle one can assume there was a happy balance between hardness and flex.

Gavin might be mentioning some armour I worked on and as I do not work there I assume it is no longer an issue to talk about it. Sadly it likely is in a box. With so little money in museums I worry about these ancient items very much. If only I had a few million..... The armour was rather thick and clearly blackened to mirror iron/steel armour of the time. Even had hinges. Interesting stuff! We had arms as well. It was part of a late 16th, early 17th 3/4 harness that had a close helmet and cuirass.of steel

RPM

[Mac]

The armour was rather thick and clearly blackened to mirror iron/steel armour of the time. Even had hinges. Interesting stuff! We had arms as well. It was part of a late 16th, early 17th 3/4 harness that had a close helmet and cuirass.of steel

RPM

Randal,

Is this part of the armor in question? I just found this on the web....I have no idea where it is.



Mac

[Mac]

Here's another good straight on view of the rerebrace. It has clearly lost a bit of material in the last hundred years.



The pic is lifted from Dobson's site.

Mac

[RandallMoffett]

Mac,

Yes it is. York Castle Museum. It is part of a 3/4 harness. I have the old call number somewhere as well as more pictures. This was when it was being moved. I think these are pictures that Steve from My armoury took when he visited and I showed him around the museum.

Several parts had steel/iron reenforcments and such.

The rerebrace was missing a few chunks and if I remember right had an internal leather lining which is also missing some parts but I still think your pattern is about what I'd assume it would look like whole.

RPM

[Mac]

Randal,

Have you got any more pics of this stuff?

Mac

[Buster]

That is cool, despite the color. Is the entire thing primarily leather, even the couters? I'm guessing that would have to be quite rigid to function properly.
As for the British museum rerebrace, I've heard it has a liner on the inside, either cloth or leather. I doubt that it weighs much, but it it might add slightly to the overall weight.

[RandallMoffett]

Mac,

Not sure. I will check. Hard drive and external died nearly the same day and much of my old images were lost. I do think I may have some more photos. The goal was to make a new catalogue but not sure it happened.

Buster,

The lames and most of the parts were leather. The ring at the top of the rerebraces were iron/steel. There was also wire/rod in some of the edges to give ti more support.

RPM

[James B.]

Looking at the varied finds it seems to me the Brit example and the one in the German chest we talked about a few years ago had no metal attached and were fairly thick when you can see the edges. 12-15 oz seems about right looking at the edges.

On the other hand the splinted arm armors had much thinner leather even thought cuir bouilli shaping is suspected in those finds too.

[Mac]

James,

I think the one you are thinking about did have traces of splints. It was this one...yes?
http://beeldbank.cultureelerfgoed.nl/al ... ondst+1937

Mac

[James B.]

I see it now. Wow thick and has splints too. It also seems to be two thicknesses of leather looking at the rearbrace and the one vambrace.

[chef de chambre]

Mac,

Yes it is. York Castle Museum. It is part of a 3/4 harness. I have the old call number somewhere as well as more pictures. This was when it was being moved. I think these are pictures that Steve from My armoury took when he visited and I showed him around the museum.

Several parts had steel/iron reenforcments and such.

The rerebrace was missing a few chunks and if I remember right had an internal leather lining which is also missing some parts but I still think your pattern is about what I'd assume it would look like whole.

RPM

I am going to assume its intended use was likely for sport. Given the prevelance of holster pistols in mounted combat from the last third of the 16th century, it would seem cuirbolli would be next to useless in cavalry combat by that date.

[RandallMoffett]

I don't know Chef. As arm and leg armour is going out might also be intended for melee use and being lighter than the steel versions would fit a specific need.

James,

Maybe. It looks like not all of it is very thick. Looks to be doubled in some places at least. Are these the ones that went missing during WWII?

RPM

[Andeerz]

Hi guys!

I wanted to point this out... read the 2nd post by Chris Dobson: http://www.myarmoury.com/talk/viewtopic.php?t=26414

In the hardened leather vambraces he made, he used a method similar to one described by Cenino Cenini for helm crests and got pretty good results with half-tanned leather. To harden the soaked leather (soaked in water and hide glue), he simply left it out in the sun for a loooong time (presumably the summer sun), then painted with several thin layers of gesso (the real stuff... hide glue plus plaster...), paint for decoration, and then a varnish (a nice period varnish methinks would be an amber varnish). I have yet to try it out myself due to school obligations and the fact that it is not quite yet hot enough to do here in Arizona... and I can't wait for Mr. Dobson to come out with his next publication on his construction techniques!!!

[Russ Mitchell]

and there's the plaster again....

[Kilkenny]

and there's the plaster again....

I have a theory that the gesso is just there to give a nice surface for the painted decoration and that the entire glue aspect of the process may be unrelated to hardening the leather and just a product of gessoing the stuff. I don't think we'll ever have a way of knowing for sure either way...

[Russ Mitchell]

I don't know myself. If leather fibers were VERY open due to moisture, very small flecks of marble dust would be able to penetrate, and those would get locked inside the fibers when the moisture was gone and the fibers naturally glued back up (17-22% moisture).

I don't currently have any veg-tan on hand, as I'm currently working with my hungarian-tan stuff, but I suppose one could do a side-by-side test painting on straight hide glue vs. gesso and see if there were any appreciable differences besides the latter having a markedly superior painting surface.

[Andeerz]

I am pretty confident that the plaster would have nothing to do with the hardening of the leather at least. It would aid in the rigidity of the finished piece, though. According to Chris Dobson's article on making his hardened leather arm harness (not the splinted vambrace, mind you), the gesso was added AFTER the water and glue hardening. He made rondels as well, and those were made with two layers of ~3mm half-tanned leather soaked in water and hide-glued together before baking. Mr. Dobson claimed that those double-layered rondels were extremely hard and inflexible, and this was before the addition of gesso and paint.

[Kilkenny]

I think part of my point may have been missed. I am suspicious that the only reason the hide glue is in the equation is as part of the gesso. I don't feel, from my own work making hardened leather, that the presence of hide glue adds anything useful to the hardening of the leather.

I can see where a layer of gesso gives an improved painting surface - and I wonder how same holds up to environmental factors, not to mention weapon impacts
Makes for some basis for arguing that such highly decorated pieces were for parade or tournament and not for work-a-day use.

Can't prove it, but I think there's some logical basis for the thought.

[Russ Mitchell]

I'll have to snag some veg-tan and do a test, Kilkenny, but I have a strong suspicion that you're right.

[Andeerz]

Snag some half-tanned, if you can! They behave differently from one another and behave differently at different thicknesses.

Kilkenny, do you use half-tanned much? And what thickness do you normally use?

Oh! And about the British Museum rerebrace talked about above. The actual cuir bouilli part is 3mm in thickness and has a liner of similar thickness which might not be original (according to Chris Dobson's "Tough as Old Boots" article). Keep in mind, though, that this thing has been through a lot of trauma and the thickness might not represent it's actual thickness when in use.

And I'll test out the glue thing out, too... But I suspect it actually did serve a structural purpose, at least in instances where there were layers of leather glued together. Plus, I wonder if it doesn't make a difference for thick leathers but does make a difference for thin leathers. Also, hide glue dries very hard, and if you allow the glue to penetrate into the leather, I wonder if it would reinforce it the way hide glue stiffens linen in a linothorax.

[Russ Mitchell]

Andeerz, I'm not made of enough money to get more half-tanned. The last batch I got cost me an arm and a leg.
I do, otoh, have a nice moose hide sitting right in my freezer that I might half-tan in workable cuts. Not half-tanning a full hide again, though. That was a pain in the ASS.

My experience has been that it makes no difference at all for thin leathers. I have (and I may just not be as good as Kilkenny), ZERO success in getting what I consider a quality product when doing this stuff with thin fully-tanned leather. I'm still totally shot on having a last, though, which could make a big difference.

[Kilkenny]

Anderz, getting half-tanned leather over here is difficult. It just does not appear on the market. Russ was able to provide me with some, and Kel had some turn up in the course of his work that he was able to kick my way, so I've done a few pieces. I would love to work with it more, but I can't find it.

All of my hardening is done with leather of at least 10 oz (some day I will learn to convert the weight to an actual thickness...)

Something I found with one half-tanned experiment that was very interesting - I made two elbow cops, one from half-tanned and one from fully veg-tanned leather. Same dimensions and same process. when finished, both were "hard", but the fully tanned was more rigid. The really interesting thing was that I could completely invert the half-tanned piece and pop it back to normal. Trying to do that with the fully tanned piece cracked it right through.

The hardened half tanned is not as rigid/stiff as fully tanned, but is an entire order of magnitude tougher.

Russ - I can't harden the thin stuff - although the whole etui thread that Mac's been working on shows how it can be done and where the glue may play an important role, at least for the thin leathers. Another reason I think that not all references to cuir boulle are talking about the same thing.