Bark Tanning: Currying

Bark Tanning: page 6

Currying

"Currying is defined as "the preparation of tanned skins for the purpose of imparting to them the necessary smoothness, color, luster and suppleness".
Mark Odle, The Book of Buckskinning VII

Contents
Intro & History
Tannins & Tannin Sources
Hide Preparation
Making the Bark Solution
Soaking
Currying
Softening & Finishing

Traditionally in Europe, currying was carried out by specialized tradesmen in an entirely different shop as it is an art unto itself. How exactly this is done, again depends on what you are looking for in the final product. First we'll give you the general rundown, and then cite specific methods for specific types of leather.
Once the hide is tanned as thoroughly as you want it, rinse it in fresh water for a couple hours. Between each rinse use a slicker and a beam to squeegee out the liquid. (We've done this using our wetscraping tool on the flesh side of the hide, putting a towel between the hide and beam to help protect the grain layer from tearing). Your are trying to remove as much unfixed tannin as possible. A slicker can be a round, smooth rod or a hand-sized, rounded edged slab of glass. Slickers can also have slate, brass, copper or heavy glass blades. You want to be real careful not to tear the grain off.
Next the hide is dried a bit, then greased and softened. Any dyeing should be done before oiling the skin.
Dyeing

A Couple of Dye Recipes

Black, from A.B. Farnham: "A good black may be made by putting clear iron filings in 1/2 gallon of vinegar and letting it stand a few days. Add enough filings from time to time so there will always be some un-dissolved. Sumac solution is made by crumbling ten or fifteen pounds of dried sumac leaves into a barrel containing thirty-five or forty gallons of warm water." "Stir it well and when cool hang the sides or strips in it for about two days. Plunge and stir frequently and on taking out rinse off any particles of leaves, drain a few minutes and brush over with the iron liquor. Rinse off any excess and put back in the sumac over night. If not black enough the next morning, repeat the brushing with iron liquor and return to the sumac for twelve hours more. On completion, rinse well, scrub with warm water and then wash for some hours with several changes of water."
Red, from Edna Wilder: "To prepare alder bark, the Eskimos scraped the bark in fine pieces, mixed it with a little water and let the mixture stand for a day or so. If they wanted it darker they would boil it for just a few minutes first. They applied the tanning solution generously to the skin in the evening and let is soak overnight, turning it once. The brightest alder color, came from bark collected just before snow, after the first hard freeze (ed. note: I've read this in other sources too). They scraped it off in very fine pieces and rubbed it directly on the skin to be dyed. The dryer the skin the quicker it took the dye. Some skins required two or three applications."

At this point your bark tanned hide will be whatever color was imparted by the tannins, usually a tan or reddish brown. Once the hide is oiled, this color will darken somewhat. If you want to change the color of the skin, you can soak the hide in any tannin based dye. There is a good chapter on dyeing in Steve & Tamara's Wetscrape Braintanned Buckskin.

Oiling

Oiling the bark tanned hide makes it dry softer, darkens it and prevents it from cracking...much like oiling a pair of leather boots. Neatsfoot oil, olive oil, tallow, brains, bear fat and fish oil have been used to finish bark tanned leather. Using tallow (a waxy body fat from deer, elk, cows and other ungulates) imparts a heavier feel and more water resistance to the leather. Using a light oil such as neatsfoot, fish, bear or brains results in a lighter, stretchier leather.
The hide should be damp with all excess water expelled by working it on both sides with the slicker. Stretch the hide in all directions. Oil is then spread evenly on the hide and it is either worked soft as it dries or not depending on the type of leather desired. When the hide is dry, it can be lightly dampened or "damped back" by rolling it up in a damp towel. This process of oiling, working and drying can be repeated until you get the softness you desire. When the hide has dried, any surplus oil or tallow can be removed with a rag. To smooth the flesh side, it can be "sleeked" with a slicker.

Various activities in a currying shop. Note the men at the table using 'slickers'.

A.B. Farnham, describes different finishing methods

To finish sole leather, lay the sides or strips down and press out most of the water by covering with some old dry cloths and treading over the whole surface to compress the fibers, then hang up until they are only damp. While still damp give them a good coat of oil on the grain side only, and hang up again until fully dry. Sole leather can be waterproofed by greasing heavily. Recipe: 3 parts tallow to 1 part fish or neatsfoot oil.
Harness and belting are finished by taking the still quite damp hide, pressing out the rinse water, slick over the grain side thoroughly and give it a liberal coat of neatsfoot or fish oil. Hang up or better, take out, spread smooth and let dry slowly. When dry, damp back by wetting or rolling up in wet burlap until damp and limber all over. Prepare a stuffing of equal parts tallow and neatsfoot oil (or fish). Heat them together, and allow to cool until soft and pasty but not liquid. Apply a thin coating to the grain side while it is warm and hang them up to dry. When dry remove the surplus stuffing by working over the grain side with the slicker. If there isn't enough grease in the leather yet, dampen back again and repeat the process of greasing, drying and slicking. Finally rub over with sawdust to remove a surplus of the grease.
Softer leathers are finished by oiling the damp leather, stretching out and drying, damping back, slicking, staking and drying. Repeat if necessary. Do not apply tallow or heavy grease to light skins and spend plenty of time slicking and staking it.