First test with cuir bouilli
29 Dec 2022 - mvj
I want to try the boiled leather techniques - cuir bouilli - for leather hardening in my quiver project. I’ve read a number of informative sources on how to harden leather with different techniques, what to expect, what to watch for, and how to get it done:
- Leatherworker.net discussion with descriptions and links
- David Friedman on cuir bouilli (and why not to use beeswax)
- Marc Carlson on cuir bouilli, with many references and quotes (through Wayback Machine)
- Jason Timmermans with a very extensive experimental exploration of 16 different methods (heat, mechanical, chemical) for hardening leather, with sources and with concrete tests of brittleness, ability to withstand blunt force, piercing force, cutting force, and response to high and low temperatures
Jason Timmermans in particular pointed out the need for pre-soaking leather in water first (so that the thermal (or chemical) action is not simultaneous with just water penetration).
With these sources in mind, I did a first test of water forming and hardening, using scrap leather from Slöjddetaljer in Stockholm. I cut three small pieces, and:
- Soaked all three in cool-from-the-tap water for several minutes. At least until I could see no more bubbles forming, but even as I was poking and prodding, the leather did not seem particularly much looser or malleable than when I started.
Then I
- Wiped water from one piece, bending it around a candle and taping it down to keep it in place as it dried.
- Put one piece in hot-from-the-tap water, keeping it submerged for about 1 minute. Then wiped the water off, bent it around the candle and taped it down.
- Put one piece in water straight from the kettle (somewhere near 100ºC / 200-210ºF) and kept it in until it started darkening. Then wiped the water off, bent it around the candle and taped it down.
All three pieces after this treatment will flatten out with sufficient force (easily enough that I can do it by hand), but feel stiff and hard, noticeably more than the leather piece I took them from. The boiled leather piece is quite a bit darker in shade, especially around the edges, than the other two pieces and gives a wooden crisp knocking sound when I tap it against the table while the other two pieces give duller, more leathery sounds when I tap them.
I’m growing increasingly confident in wanting to use nearly boiling water to harden the leather for my quiver.