Tanning

This section starts with a dried, stretched, salted skin/hide. I will put up a section on skinning/fleshing/stretching next time we butcher, probably this fall.

These pictures show tanning a small sheepsking with wool on. Tanning for leather is basically the same, I will add notes when leather would be done differently. There are many ways of tanning, here I describe a method that has worked well for me. I will add notes about alternatives in some places.

The dried, salted skin first has to be soaked. If it won't all fit in your tub/basin, put in part of it and get it wet. After a few minutes it should soften enough that you can fold it and work the rest in. Soak time will depend on the size and thickness of the skin, but will be at least several hours, and I typically soak overnight. Soaking much longer than that risks the hair starting to slip (not a problem if you're going to remove the hair anyway). Once the skin is nice and flexible, I dump the water out, refill with clean water and add Dawn dishwashing detergent (sounds odd if you're not familiar with it, but Dawn is highly recommended for washing wool). Swish the skin around and let it soak for up to an hour. This helps get the blood and dirt out of the wool. Then rinse a couple times, just enough that the water starts running fairly clear. At this point I like to scrape the flesh side again -- it should have been mostly cleaned up before being stretched and salted, but there are usually a few bits that were missed and this is your last chance to clean it up before tanning.

Place the skin on a fleshing beam, flesh side up, and scrape with a knife. There are various methods for doing this, I like to use a knife that is a bit sharp, but not super-sharp. The sharper your knife, the easier it will be to clean the skin, but also the easier it will be to cut holes in the skin by mistake. I usually scrape with the blade edge following the spine of the blade, as shown in the picture. Scraping the edge first is more aggressive but also more risky. Mostly you want to be scraping, not cutting. Work lightly all over the skin, looking for any bits that were left from the prior fleshing.

Not sure how well you can see them in these pictures, but here are two places that needed a bit more work. Lefthand picture shows a small strip of muscle that was still attached to the skin. Righthand pictures shows a layer of fiberous tissue that had been broken up a bit, but not removed. I scraped both of these off before proceeding.

Once the skin seems good and clean, it needs to be pickled - soaked in an acidic solution to open up the pores and get it ready for tanning. In recent tradtion this was often sulfuric acid, but I avoid working with sulfuric acid as much as possible. Here's an alternate recipe from Van Dyke's Taxidermy (see Supplies):

1 gallon water
1 lb salt (non-iodized)
3 oz citric acid ("pickling crystals")

Multiply the recipe as needed for the size of your hide. You need enough volume to submerge the hide, but pickling will not "use up" the solution, so if you have several hides, you can keep re-using the solution (if you have a lot of hides, you may need to add a bit more acid periodically, check the pH to see). Van Dyke's says to soak for at least 72 hours. I usually do 2-3 days, a bit longer for larger hides. Give it a stir at least once a day, more often if you happen to be passing by. While you're waiting, mix up the alum tan (recipe below) as it needs to be done a day or two before using.


(These plastic tubs are great for tanning! Most feed supply stores carry them for under $10)

Once the time is up, the extra acid needs to be washed out of the skin. I do a water rinse, then let the skin soak in water + some baking soda for 15 min or so, then rinse again. Squeeze or let hang to remove most of the water, and you're ready for the tanning solution.

Alum tan (recipe from Van Dyke's, I've seen other recipes that are pretty similar). As with pickle, multiply to get the volume you need. I like at least 5 gallons (total) for a small/med sheep or goat skin, more for a larger skin.

Part 1:
1 gallon water
1 lb aluminum sulfate

Part 2:
1/2 gallon water
1 cup salt
4 ounces sodium carbonate (washing soda)

Mix up each solution and stir to get well-dissolved (may have to let sit overnight). Now place one solution in a container several times larger than the total volume of solution (can be the container you mixed it in, if it is large enough). Pour in a little of the other solution and stir. You will get a lot of bubbles foaming up -- this is why you need a large container! Once bubbles have died down, add a little more and stir. Once you have totally mixed the solutions, give it another stir and let sit a couple hours or overnight to finish the reaction. Your tanning solution is now ready.

Submerge your pickled and neutralized skin in the tanning solution, and give it a stir at least once a day. Most sources say tanning will be complete in 2-7 days (depending on size/thickness of the skin) but I've had better results if I leave it at least a week for smaller skins, and two weeks for larger skins.

Once the time has elapsed, remove the skin from the tanning solution (which can be used again), and thoroughly wash it. Any remaining salt will form a white crust as the skin dries, and any remaining alum will make the hair stiff and sticky. I have had good results by doing an initial rinse to remove most of the salt, then washing the skin with Dawn dishwashing detergent, letting it sit in the wash for 30 min or so, and then rinsing about six times. If the water still seems dirty or cloudy, do a couple more rinses. The initial rinse and the wash water will contain a lot of salt, so dump those out on a gravel driveway or other surface plants are not growing. The rest of the rinses can be used to water plants.

After the final rinse, squeeze as much water out of the skin as you can and hang it over something to dry (spread out, above left). You need to work it as it dries, so check it periodically. A wet sheepskin will take a long time to fully dry, but the edges will dry much faster than the center. If the edges are drying out too fast, or you won't be able to check on it for a bit, fold it up with the edges inside (above, right). Working the skin as it dries takes practice. The critical part is to recognize how dry the skin is. If you try to work it too wet, you won't have any effect. But if your try to work it too dry, it will be very difficult and still not give good results.

Watch for areas where the skin starts to turn darker and get a little stiffer as it dries (center of left image). Try pulling in these areas to stretch them out. If it stretches easily and stays the same color, it's still too wet. If you have a hard time stretching it at all, it's too dry. If it stretches with only a little effort and turns white, and stays white when you let go, it's about right (center of middle and right images). Keep checking it periodically and stretching out all the areas that are starting to dry. If you run out of time or energy, roll up the hide, place it in a plastic bag, and stash it in a cool place. If you leave it in the bag more than a day, it may start to mildew but I've had no problems over a day. This also has the advantage that while sealed up the moisture tends to equilibrate -- the dry areas get damp again, and the wet areas dry out. This can be a big help if you let an area get a little too dry.

It is very useful to have a wooden stake for breaking the hide. This is simply a board with an acute but rounded edge. By dragging the skin over the edge of the board you can stretch it out and separate the fibers. This is not a fast "rubbing" action, but rather a slow stretching. While the hide is damp, the stake will "grab" it enough to give you a good stretch. Once the hide is drier, it will tend to slide over the stake, so you will need to pull down on both side, but pull harder on one side so the hide is stretched as it slowly runs over the stake (see arrows in images above). I used the stake a lot at first, but I am doing more and more by just pulling on the hide to stretch it and using the stake to even everything out. Hardwood is best for the stake, but I had pine so that's what I used. It has worked okay, but has a tendency to crack and splinter.

I also have found it useful to put a rounded point on a section of dowel rod. This is great for working small areas that aren't stretching well. For best results, stretch the whole area, while rubbing the problem spot with the end of the rod.

Keep working the hide as it dries, watching for any spots that turn dark or get hard. The stretching goes easily if you catch the hide at the right time, but if you let a spot dry out too much it gets a lot harder to soften it up. Thicker areas will not soften as much as thin areas, but should still be fairly flexible. If you let a skin dry out too much and it gets hard, in theory you can soak it and re-break it as it dries, but I have not had much luck with this. You're much better off trying to break it as it dries the first time.

Once the skin is fully dry, you're done! If it is your first time tanning, it probably didn't come out quite as well as you'd hoped. Take what you've learned and try again, next time will be better!

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