Vegetable tanning is an ancient method of preparing animal hides; the word "tan" comes from "tannin," which is the ingredient in vegetable matter that bonds with the proteins in the hide and turns it into leather. Veg-tanning is a labor and time-intensive eco-friendly alternative to brain or chrome tanning. The method produces a sturdy leather that's used to create saddles, purses and gun cases -- and the material works well for tooling projects.
Things You'll Need
Ground tree bark
Rainwater or other soft water
3 large barrels, tubs or vats
Dull metal or plastic blade
Prepare The Hide
Cure the hide by soaking it in a salt brine solution to which you've added a few drops of disinfectant. The curing process takes about sixteen hours.
Soak the hide in fresh water for several days to remove salt, fats and other debris.
Soak the hide in a solution of lime and water for at least 24 hours. This will loosen the hair.
Remove hair and any remaining membrane from the hide with a dull-edged scraping tool.
De-lime the hide by rinsing it under running water for at least 12 hours.
Preparing Bark Tanning Solution
Grind a quantity of tree bark that weighs about twice as much as the hide into a fine powder.
Extract the tannin from the ground tree bark by simmering it slowly in soft water for several hours or soaking in cold water for several days. The more you boil the extract, the darker your finished product will be.
Mix your extract with an equal amount of water for the first soaking.
Tanning the Hide
Immerse your prepared hide in the tanning solution -- draped over sticks or dowels -- so that there are few wrinkles.
Stir for the first ten minutes, and then every ten minutes for the first hour. Re-adjust the hide frequently, to allow every bit of it to be fully and equally saturated.
Allow this to soak for several hours, at least. Many tanners recommend one week. Stir it regularly.
Remove the hide. Discard the first solution and re-immerse the hide in a stronger solution, building the strength gradually through several weekly increases until after 4-6 weeks you are using full strength. Continue to stir the hide often, to ensure thorough penetration.
Only the first solution needs to be discarded, to remove all traces of lime. You can then increase the strength by adding more tannin.
Leave the hide immersed in the full strength solution for 4-6 months. Continue to stir several times a day. The hide is done when the color has been absorbed through to the center of the hide; you can check by cutting off a small piece from an inconspicuous spot. Longer soaking will produce stiffer leather.
Experienced tanners vary the process slightly- length of time, preparation of solution- to produce different results. Feel free to experiment with the basic process outlined here.
Use different barrels for the salting, liming and tanning processes.