Blackening steel with an authentic process?

[Sean Powell]

Hello,

More then occasionally the Design and Construction section has a discussion on the best way to blacken armor. Everything from modern acid based chemical solutions to weed-burners with WD-40 to rubbing with linseed oil while still hot. Results and quality vary a LOT based on technique as does the durability of the finish. We know some armor was blackened, especialy those nice English Civil War B&W harnesses and you would think we would have decent documentation of the process. I was asked offline about the period process and honestly I don't know of any documentation for the HOW, just that it was done. All I have found on the archive so far is:

"According to Cennini, Lamp Black and linseed oil makes what he calls "armour black", and that is basically a crude black oil paint. Craig baked such a finish on a munition cevelier he made, and that was sort of dull, but I wager if it were left to dry, it would be a semi-gloss."

Anyone have a more complete discription of what Cennini described or have any alternate documented processes? Or is this one of those "Everyone knew it, why write it down?" sort of things.

Thanks in advance,
Sean

[Thomas Powers]

Have you looked at Theophilus' Divers Arts where he blackens some small items of ironwork?

[Sean Powell]

Not yet but apparantly there is an english translation available online so I know I'm going to be busy this evening.

http://books.google.com/books?id=wo4EAA ... &q&f=false

Any other sources anyone can think of?

[Signo]

Cennini is an artist, a rapid read of his work, say that almost everything is related to painting. There are some parts about making a oil paint that can stick to stones and even to metal, there are even parts about making glue, but when he talks about colors, he mean colors for painting, so, this "armour black" I think he mean a color that matches the color of real, blackened armour.
As a side note, I had not found this part in the italian version.

[Signo]

According to a restoration website, "lamp black" is a black tint obtained with special lamps that burns resinous woods, it may have some sky blue tint in it.

[Sean Powell]

Signo,

Thank you, I had reached pretty much the same conclusion. I believe that "lamp black" is the soot left inside a lamp from a dirty candle wick or oil lamp running too rich. Its a very matte black powder that gets on anything it touches and should have been readily convenient in every household in the medieval time-period. I can easily see how it would be turned into a colorant for paint... but not for armor.

There is a process for blacksmiths to oil-blacken hinges, latches and other exterior iron-work with heat and oil. The process varies somewhat based on the size of the piece, heat-source and type of oil. Unfortunetly I'm finding very little documentation for ANY time period, even the 1900's. I assume it's in "Complete Blacksmith" but that book is packed. I was hoping to find a similar description prior to 1600.

If anyone has any other sources I can try I would be very grateful.

Thanks,
Sean

[Jeff J]

I've oil blackened metal using the cooking grill with linseed oil. I've also done it with linseed and lampblack and baked it on. Lampblack gave a deeper color, faster.

Try some experiments! Lampblack is cheap, from many art supply stores.

[Thomas Powers]

Linseed oil blackening is mentioned in Divers Arts; pretty much pre plate armour though

[Sean Powell]

I've oil blackened metal using the cooking grill with linseed oil. I've also done it with linseed and lampblack and baked it on. Lampblack gave a deeper color, faster.

Try some experiments! Lampblack is cheap, from many art supply stores.

I've done some nice things with heat bluing and light in-organic oil(I like my wifes penetrating sewing machine oil). I've gotten some amazing blues and golds... but just because I CAN do it doesn't mean I can DOCUMENT doing it properly.

A friend came to me to help her with documentation for a little side-portion of an A&S project and I thought "This will be easy to document. We talk about oil blackening all the time." Problem is we only seem to talk about the experimental side, not the documentation side. Surely there must be SOMETHING about it, especially with all the B&W harnesses?

Sean

[Cet]

PM Wade, I recall him mentioning that the black on at least some B&W pieces was originaly painted.

[Cet]

PM Wade, I recall him mentioning that the black on at least some B&W pieces was originaly painted.

[chef de chambre]

Lamp-black & linseed oil = Oil Paint.

[Matthew Amt]

Isn't black sort of the "default" for any iron or steel that was forged? You have to go to some effort to make it shiny. I often make modern nails and bolts look not-modern by sanding off any galvanization and just heating with a propane torch, sometimes adding a couple hammer-taps to make it look forged (which at that point it actually is!).

But yeah, for blackening a finished armor piece, I've just used heat and oil or wax. Though getting a *nice* finish may take a little more work!

Years ago I heard of a stove-blacking compound that some armorers in England used, Z-Bright or Z-Brite? No idea if anything like that is still on the market. But it gave a very nice even matte black finish.

Matthew

[Thomas Powers]

Anything in the Boke of Natural Magick? I remember a long list of very odd suggests for quenching liquids that was abstracted from it.

[Signo]

As I said many times here, an old (don't know how old) recipe for a black paint, involve sulphur and turpentine. The paint that is obtained, once flamed after applying it, turn gummy, glossy and black (it's yellowish before the last heat treatment). Scratches can be repaired with a flame touch.

Warning: you may easily set your whole county on fire while making this paint.

[woodwose]

Lamp-black & linseed oil = Oil Paint.

Expanding on that, go to an art supply store and there will be a tube of oil paint which is made of linseed oil and lamp black, and this paint will be called "lamp black". In same little rack of paints, all made by the same company, there will probably also be "mars black", "ivory black", and "bone black". I'm not sure about mars black, but bone and ivory black are/were made from the soot from burned bones and ivory (I don't remember what is currently used in place of ivory, probably bone and some other additive).

I've thought that the oil and heat method people use for blackening helms is pretty much making a something similar to lamp black oil paint, as it starts with oil and then burning the oil turns some to soot. So it makes sense to me that adding lamp black pigment to the oil would help to deepen the black that results in the end.

There was something else I was going to mention but I don't remember what it was - I started replying to this yesterday while on the road from Maine to Michigan.

Edit.. linseed oil was an oil used for making oil paint in sca period. Walnut oil was also used in sca period, though mostly by artists in northern Europe.

[Thomas Powers]

DIvers Arts mentioning blackening copper by smearing it with linseed oil and heating it over coals, repeat as necessary---sound like anything folks have done lately?

Also file (iron) smooth and heat it and rub it with oxhorn or goose feathers to provide a black coating

[Dan Howard]

DIvers Arts mentioning blackening copper by smearing it with linseed oil and heating it over coals, repeat as necessary---sound like anything folks have done lately?

Jeffrey Hildebrandt's recent reproduction of the Bidford-on-Avon Anglo-Saxon shield boss. The steel was "heated to a dull red and dipped in linseed oil to obtain an iridescent black. Several layers of linseed oil were then baked on for additional darkness, depth and corrosion resistance."

http://www.myarmoury.com/talk/viewtopic.php?t=28840

As usual, Jeffrey has done beautiful work. It looks like a pretty durable finish.

[The Iron Dwarf]

z brite or similar is still on sale here for blackening old stoves and fires it has graphite in it these days

[Thomas Powers]

Graphite sometimes used to be called "lead" as in pencil leads

[Dan Howard]

Graphite never "used" to be called lead. It is called lead today because, originally, the cores of pencils were actually made from lead.

[Thomas Powers]

So the black lead for stoves 100 years ago wasn't called lead---Guess I had better sand it off the antique can!

I saw dozens of references to plumbago in "Sources for the History of the Science of Steel" when they were referring to graphite in the 1700's, e.g: "It is no longer pure charcoal, but it is plumbago; that is to say, the same substance of which English pencils are made" SftHotSoS pg 342

Can you please share where you got your information?

[The Iron Dwarf]

lead in modern pencils is IIRC graphite and something like clay, more graphite means softer pencil.

real lead used to be used a lot more than it is now ( though it is still used in some suprising places, recently I was working on a historic building, a major restoration, one wing alone cost 50 million pounds I believe, the nursery had to be painted entirely in lead based paints because of the buildings history ).

[Thomas Powers]

The "english" pencils of the time were graphite from the mines in Wales IIRC and the context of charcoal turning to plumbago was definitely referring to graphite and not real lead, Pb.

It's a good read and Cyril Stanley Smith is a respected scholar in the history of technology fields especially in metals!

[Derian le Breton]

Not yet but apparantly there is an english translation available online so I know I'm going to be busy this evening.

http://books.google.com/books?id=wo4EAA ... &q&f=false

Any other sources anyone can think of?

There's a dover print as well.

I'd also look at Biringuccio.

-Derian.

[Dan Howard]

So the black lead for stoves 100 years ago wasn't called lead---Guess I had better sand it off the antique can!

I saw dozens of references to plumbago in "Sources for the History of the Science of Steel" when they were referring to graphite in the 1700's, e.g: "It is no longer pure charcoal, but it is plumbago; that is to say, the same substance of which English pencils are made" SftHotSoS pg 342

Can you please share where you got your information?

Apologies. I was confusing two different factoids. Early stylus/pencils were made of lead. But you are right that graphite was initially confused for lead ore.

[Thomas Powers]

No harm, no foul! I've done my share of oops posts over the years.

It could be a thread on it's own about things that medieval folks confused/thought were related to other things, (barnacle geese, kupfernickel, colouring copper with zinc ore, or all the various explinations on how iron becomes steel...or how to carve crystal in Divers Arts for that matter)

[wcallen]

PM Wade, I recall him mentioning that the black on at least some B&W pieces was originaly painted.

Later comments about linseed oil being the basis of paint is very true. So there isn't really as clear a line between oil + heat and paint as we often think.

It is always hard to be 100% certain whether a surviving finish is actually original, but I think that there are enough pieces that have survived without going through dealers' and collectors' hands that we can draw some reasonable conclusions.

I own several black pieces of armour. I have seen a lot more in public collections as well as private hands. I think I can reasonably claim that some are originally black from oxide (heat) which may have had some help with oil, and some which are most definitely painted.

I expect that most of the painted ones were painted over a rough, oxide black finish underneath - because that is the natural state of steel that has been hot and cold worked before the surface is ground smooth.

Wade

[Sean Powell]

OK, Thanks Wade and everyone else. I suspected forge black and oiled was the most common method but you never know when there will be a line in Diverse Arts "Dip ye the warm metal in oil of pressed walnuts shells and heat again until the oil smokes but does not burn." Or maybe an inventory for the tower of london recording "5 calf skins died white, 20lb of arming nayles, 1 hogs head of nut oil and 6 lbs of fine powdered carcoal for the maintenance of the royal armories." Ultimately there are probably hundreds of variations but any competent smith can blacken steel like any competent cook can scramble an egg... Finding DOCUMENTATION on scrambled eggs is probably as hard as documenting blackening techniques. (and someone is about to post a recipie for scrambled eggs to prove me wrong)

Thanks all!
Sean

[Thomas Powers]

We have few enough good sources on ferrous metals that anyone interested in the field can amass many of them in english even! It's finding the oddball ones that make life *interesting*

So:
Theophilus, Divers Arts, c 1120
Biringuccio, Pirotechnia, c 1540
Agricola, De Re Metallica, c 1556
della Porta, Magia Naturalis, c 1558

Over the line we have: Moxon's Mechanics Exercises and even further out Diderot's Encyclopedia

*Please* add your own favorites; my research library is about 200 miles away during the week! (so I don't have the Berg Buchs at hand to list)

[Mega Zenjirou Yoshi]

Lamp-black & linseed oil = Oil Paint.

Expanding on that, go to an art supply store and there will be a tube of oil paint which is made of linseed oil and lamp black, and this paint will be called "lamp black". In same little rack of paints, all made by the same company, there will probably also be "mars black", "ivory black", and "bone black". I'm not sure about mars black, but bone and ivory black are/were made from the soot from burned bones and ivory (I don't remember what is currently used in place of ivory, probably bone and some other additive).

I've thought that the oil and heat method people use for blackening helms is pretty much making a something similar to lamp black oil paint, as it starts with oil and then burning the oil turns some to soot. So it makes sense to me that adding lamp black pigment to the oil would help to deepen the black that results in the end.

There was something else I was going to mention but I don't remember what it was - I started replying to this yesterday while on the road from Maine to Michigan.

Edit.. linseed oil was an oil used for making oil paint in sca period. Walnut oil was also used in sca period, though mostly by artists in northern Europe.

All the Mars pigments are iron oxide in various shades. Most have many names, Mars red is also called Venetian red, light red, and so on.

Mars being the god of war, iron is his element, hence the name.

[Harry Marinakis]

Any blackening process that generates soot results in a rather filthy set of armor. If you wear armor blackened by that process, your clothes and your skin will quickly change to a uniform filthy shade of soot black. Throw in a little oil to keep everything from rusting and you've got a real mess. You wouldn't want to be wearing any nice clothing or bright colors....

Messy stuff to wear for any length of time.

[woodwose]

Any blackening process that generates soot results in a rather filthy set of armor. If you wear armor blackened by that process, your clothes and your skin will quickly change to a uniform filthy shade of soot black. Throw in a little oil to keep everything from rusting and you've got a real mess. You wouldn't want to be wearing any nice clothing or bright colors....

Messy stuff to wear for any length of time.

As with anything that has been painted (again, paint has two parts - pigment that determines the color, and something that the pigment has been mixed with that will eventually dry and hold it in place on the painted surface - walnut oil, linseed oil, acrylic, wax, gum arabic, etc...), if the oil and soot mixture is allowed to dry on the surface before using the item then you generally do not need to worry about getting any on you.

I've only blackened small items using oil and heat, but have not had issues with oil or soot getting on things from them afterwords. My take on it is that some of the oil gets burned into soot, and some gets baked directly onto the surface of the metal with the soot trapped in that baked on layer. I've used vegetable oil, motor oil, WD40, linseed oil, and random mystery oil. Sometimes there is a bit of residue that needs to be wiped off after burning the thing, but after that is taken of the item is still black and more did not wipe off.

I've also made paint using soot and linseed oil. Paint it on, let it dry, and there it stays (or tried to stay, as with just about any surface treatment it can be scraped off). The thing with using oil in a process where it is not being baked or cooked onto the metal surface is that you need to use an oil that will eventually dry to a hard film and not feel sticky after having a week or two to fully cure. Vegetable oil, motor oil, WD40 - are oils which do not fully dry; which is why linseed oil and walnut oil have been traditionally used in paint for centuries - because walnut oil and linseed oil will dry to a hard film, and finely powdered pigments that have been mixed with the oil will be trapped in that dried oil layer... at elast to some extent, too much pigment and it will... well, be kind of like making instant mashed potatoes and putting way to many potato flakes in - the potato mush would become dry and stiff, put enough in and eventually you have mushy potato flakes; put too much pigment in your oil and the results will be oily pigment rather than pigmented oil, and oily pigment will indeed get onto everything event after the oil has dried).