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Bark-tanning: the hide tanning method by which hides are tanned (transformed) through the plant constituent tannic acid, aka tannins

On our first weekend:

  1. Day one, we washed + acidified hides while creating bark liquor in varying concentrations.

  2. Day two, we submerged our hides in a diluted bark-liquor, mixed them for 30+ minutes, and then plunged them into a strong concentrate.

Between Weekends

I am stirring your hides daily, watching them uptake tannins and turn more into leather as we move forward. Big thanks to Linda and Jess for coming out and scudding the hides on Sunday!

If you are doing this solo:

  • Stir your hide at the bare minimum once per day

  • The more you stir, the quicker your hide turns to leather

  • Sit and stir for 5-10 minutes each time

  • Keep your hide submerged under the surface of the bark liquor

  • Scud the hide by scraping a dry scraper on the membrane side (if you have a hair-off hide, do not scud the grain side). Scud the hide once every 3-5 days. it should take about 10 minutes for one hide.

  • If your hide picks up a lot of tannins and the bark liquor looks more like water, make a concentrated batch using your take-home tannins:

    • Heat up 3 gallons of water

    • Add your 3-lb package of Mimosa

    • Whisk until dissolved

    • Take out 3 gallons of bark-liquor from hide

    • Add the 3 gallons of new, concentrated bark-liquor

Finishing our Hides

Step 1: Rinse leather of tannins

  • Lift leather out of bark-liquor bin. If it is very heavy like a sheepskin, hang it on a sawhorse or fence beam to allow it to drip-dry for 5-10 minutes. Gather the tannins in a bin if you can.

    • Next, put the leather on a wet-scraping beam and rinse with a hose

    • After the wool turns from red to white, submerge the sheepskin leather in a bin with cool water. If the water runs clear, great; if not, keep rinsing.

  • If you are finishing grain-on leather, you can simply submerge the leather in a bin of cool water. Some tanners add soap. Rinse multiple times until the water runs clear.

Top photo: Hanging a sheepskin leather rug to drip-dry (and lose water weight!)

Middle photo: A sheepskin before tannins are rinsed out

Last photo: Partway through rinsing tanning + some stuck globs of Mimosa

Step 2: Framing (optional)

  • Place hide membrane side up (grain side down/hair side down) inside the middle of a frame, on the ground in a clean area

  • Take 3 arm lengths of string. Use an Awl or a knife and poke holes into the hide - one inch from the edge + 3-4 inches apart

  • Tie the string in a slipknot around a nailhead closest to an area you want to start weaving - I recommend starting at the neck.

  • Weave the string from the hide to the frame and bacl again until the neck is secured

  • Then move across the hide and go to the haunches. Weave this part of the hide in with another piece of string, using slipknots to secure the string to the frame at each end of string

  • When weaving, simple let the string rest around the nailhead; do not knot

Step 3: Softening - the main event

  • Softening a hide means to keep the hide in motion while it dries

  • In other hide tanning methods - smoke-tanning and mineral tanning - softening is hard manual labour

  • In the bark-tanning method, softening is not physically intense. But it still needs to happen. Basically you are ‘keeping an eye’ on your leather as it dries

  • If the leather is in a frame, then the frame is stretching the hide itself. All you need to do is take a stick or a dry-scraper tool, press into the hide and slide the stick or tool around. The leather will be quite pliable and stretchy while it is wet. Use 7/10 pressure - enough to notice the leather stretching and moving

  • A dry-scraper has the double effect of taking away membrane. If your dry-scraper has one bevel (knife edge) then think, “bevel up, scrape down!” and apply pressure only when scraping away from the bevel

  • Re-tighten strings as the leather stretches, because the sheepskin will get bigger! This is why slipknots are great.

  • It may take 2 days for the leather and wool to fully dry, You don’t need to be present softening constantly this whole time. Just check on it hourly on the first day and use your stick or dry-scraper to soften it for 10 minutes at a time.

  • Once the leather and wool starts to really dry, then soften it more often. This will ensure the leather stays pliable + also, it won’t develop any dry crust on the surface. If it does develop some crust, scrape it away with the dry-scraper tool.

  • If you have a pumice stone, you can use it to scour off the last bits of membrane on the leather, once it is fully dry.

  • If you didn’t use a frame, then lay the sheepskin out on the table wool side up and let the wool mostly dry. The leather side will stay hydrated. This could take a day. You may want to leave the sheepskin laying flat overnight and then start softening in the morning.

  • Once the wool is mostly dry, start pulling the hide with your hands in all directions. Stretch it and stretch it and stretch it.

  • When taking a break from stretching, lay the leather side down on a table and flatten the hide onto the flat surface, so that rug lays flat once it is dry

  • Same as above, you will do most of your stretching in the final hour or so that the leather is drying.

Linda using a dry-scraper to soften the edges of her leather

Dee showing proper form with a dry-scraper: hold it at a 90 degree angle to the leather and scrape down (or side to side) always thinking “bevel up, scrape down!” (or, bevel left, scrape right!”)

Softening in action

Step 4: Oiling (midway through softening)

  • Once leather feels somewhat dry to the touch on the surface but you know it still has moisture in its depths, apply oil. This will be about halfway through the softening process.

  • You don’t have to get it timed perfectly. If the leather is too wet, it simply wont absorb oil. Err on the side of wetter rather than drier - because if leather is too dry, the oil will just sit on the surface but it won’t travel to the depths of the hide.

  • Get a 500ml mason jar or a 250 ml measuring cup. Mix 1/2 cup vegetable oil with 1/4 cup liquid soap (substitute 1 tablespoon of powdered lecithin for soap) in the jar. Fill up to 250 ml with warm water. Now you have 250 ml of a fat emulsion.

  • Dip your hand in the fat emulsion and rub a thin coat onto the leather. You can do this while a hide is vertical in the frame or you can lay the sheepskin on the ground, wool side down, for a flat surface.

  • Rub the oil into the leather with your hands for 5-10 minutes until it is absorbed. Apply more coats.

  • You want the oil to absorb and not have the leather feel greasy. If it feels greasy, rub the leather with a paper towel.

  • *If you are tanning full grain leather (hair off) then only apply oil to the grain side. If you are tanning a sheepskin rug, only apply oil to the membrane side.

Step 5: Combing

  • If you have a thin metal comb, use one hand to pull wool out of the way and then place the comb tines at the base (root) of the hair and pull out toward your chest. Move swiftly - use one hand to pull wool out of the way and then comb, repeat. I like to sgart at the bottom of the hide and work from side to side in a line.

  • If you have a pet brush, you can use it to comb the wool out. It tends to be much faster than a comb.