How to make Cuir boulli with extra glue hardening

Nobody knows today exactly how Cuir boulli was made historically, just that it was boiled, cooked or somehow baked hardened leather that was tough enough to use as armour, reisistive to cuts and you could paint it. Since you can't paint waxed leather and it cuts easily, it can't have been waxed, or at least that's not the main method. Instead of doing this with molten wax, I'm baking the leather and adding a natural hide glue that's been around from at least bronze age to modern times.
This is oil tanned leather. Normally you can't harden that at all, baking it just won't take, except with wax but I figured out how to fix that. But first washing the leather with Yes (for washing dishes), then soaking it in water mixed with baking soda over night gets most of the excess oil out and then you can bake it.
Baking leather is done by having it wet put in the oven at 70-85 degrees Celsius and "baking" it for a couple of hours until it gets hard. 85 degrees is where the leather will start to shrink and shrivel and turn hard but brittle, seems like a good idea at first but it's not.
The best material that gives the best result is natural vegetable tanned leather, but with the baking soda trick you can do it with other leather too.

Category:

Education

Tags:

• SCA
• Cuir
• Boulli
• historic
• leather
• hardening
• crafts
• how-to
• arts

[adriangaitan420]

you should cut your nails before recording

[Fargbollen]

@adriangaitan420 not just for videos. My brother always tells me to cut my nails. ;)

[e3con1]

I was wondering if you ever tried hide glue instead of casein and what results that would give? Great video btw!

[Fargbollen]

@e3con1 , thanks! The video actually shows me using hide glue, being stretchy instead of just strong but stiff like the casein it's probably better after all. I was going for casein because it was said to be water proof and non-sticky, but I've found out it really isn't. So use hide glue, it seems to make the couir boulli the most difficult to penetrade with blades. Still nowhere near steel plate though, these would be useable only as lightweight armour with moderate to decent protection only.

[Fargbollen]

I've ben experimenting with casein glue lately and when it dries it becomes a glossy clear and lacquer like finish. I expect this can be used instead of ahistoric (for europe) lacquer of the otherwise sticky hide glued lamellar.

[Fargbollen]

I'm putting together a batch of cassein glue now so I'll make another video with the right glue. This one works but gets sticky in wet weather. Cassein glue is water resistant but also stronger than epidermic glue.

The result compared to waxed leather is like cutting a carrot compared to a car tire. Both can be cut, but it's much harder making it a far more likely material for practical armour.

[adriangaitan420]

thanks great video

[amylea122]

Will this method of hardening work with chrome tanned leather? I have 10 lbs. of chrome retan leather and I want to make armor out of it.

[Fargbollen]

If you want to do this, try a small test piece of pure vegeable tanned leather of 3-5 mm thickness. This will show the best results. Soak in Natron sated water for a few days (room temp or something). Bake in oven up to max 85 degrees celsius with a digital thermometer with alarm to warn if it gets too hot. Set alarm to 75-80, not 85 or it'l burn and shrink excessively. It always shrinks some though. Then make a pot of cassein glue and soak the piece in it. Take out, let dry. Finished!

[Fargbollen]

@crocgator44 doesn't matter with this method. Just don't use boiling water or anything over 85 degrees Celsius. It's the baking soda that de-tans the leather togehter with the oven baking that makes it hard and still strong. Compared to this result the simple "water hardening" some still advocate as all you need is just a temporary way to form leather into shapes before baking. The dry-bake-glue method I show here is many times more cut and tip penetration resistant than any other I've tried.