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Tanning hide with Hemlock bark  RSS feed

 
Steve Nicolini
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We just got a deer hide from some hunter friends.  We want to work and tan the thing but our pals didn't give us the brain.  I have read in a few different ethnobotany books that Western Hemlock, Tsuga heterophylla, is the conifer in the Pacific Northwest with the highest tannin content.  I read that people used to boil the bark and used the solution for tanning. 

Has anyone done this?  How long to boil the bark?  Should we use the inner or outer bark?  Both? 
 
Heidi Bohan
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I helped someone tan an elk hide a couple of years ago and I suggested using the solution from a bunch of chestnut hulls I had soaking (accidentally, they were in a plastic bin outside in the rain). So I gave him a big jug of this solution, and he said it worked great (they are aso high in tannins and used historically). I think he even compared it to a tanning solution he purchased and said it worked as well.

Western Hemlock bark is so high in tannins the creeks run red in the spring just from rainfall washing through them and the roots. I'd use the whole bark, pound it with a mallet to break it down, then slow simmer it until the water is very dark and strain.

I've done brain tanning in the past, and I think the brain is more to soften the skin to remove the hair in the soaking process. And you know you can use pig brain by the way, available at most local 'real' butcher shops. And the tannins are to cure it after you've removed the hair after soaking. If you want to leave skin on, then you scrape the inner hide to remove flesh, fat etc and then 'tan' with a solution or just dry and cure in salt until you decide what to do.

I see by the post date this info is way too late!! 

Anyway, hope that helps someone.
 
Joel Hollingsworth
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heidi wrote:
I think the brain is more to soften the skin to remove the hair in the soaking process.


It's more than that, I think.  The fat in brains is a drying oil, or at least a semi-drying oil...I had trouble finding figures for the iodine number of rendered brain fat.
 
            
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Brain tanning and bark tanning will produce different leathers, so the method of tanning should be chosen on the end use envisaged for the hide.

Brain tanning produces softer buckskin type leather, where bark tanning will generally produce a tougher, much darker and also (depending on how long you tan) water resistant/proof leather, although I have read that bark tanned leather can be made more supply by really working it hard at the end.

If you want a softer leather, pig and horse brains can apparently be substituted for the original brain of the animal and you may be able to talk to a local butcher into parting with a pig's brain. Don't even want to start thinking about where you would get a horse brain
 
Dennis Lanigan
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On the remote chance anyone is actually watching this thread, I know how to tan hides with Hemlock bark. Feel free to ask me questions.




 
Adam Klaus
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Dennis Lanigan wrote:On the remote chance anyone is actually watching this thread, I know how to tan hides with Hemlock bark. Feel free to ask me questions.


Thanks for the offer Dennis,

I dont have spruce nearby, but do have oak, fir, spruce. Any idea how one of those would work?
 
Dennis Lanigan
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For tannin levels of spruce, pine, and doug fir check the USDA forest research paper "Douglas Fir: bark tannin decomposition in two forest soils" on page four it lists the tannin content of various trees. Oak is usually in the 10-15 range although I would search specifically for the species around you. If you somehow have Tan Oak or chestnut oak then you have the best tree for bark tanning there is (Lithocarpus Densiflorus). Sumac leaves are also an amazing source of tannins as you don't have to strip the bark off the plant.

As for actually using the bark:

Most people say break up the bark, boil it, make a tea. I don't think this works. I recommend a soaking technique that combines the strengths of continually soaking bark.

Schemes to get the most tannins out of barks are described in "Rural Tanning Techniques" (an old UN development paper) here www.cd3wd.com/cd3wd_40/JF/440/33-785.pdf
and "Environmentally Sound Tanning Techniques" (Tool Foundation). http://www.cd3wd.com/cd3wd_40/JF/440/33-816.pdf

I also recommend doing small scale experiments. Figure out the tannin content of your bark by doing the techniques in both manuals (there's one in Environmentally Sound Tanning I know for sure). And tan small pieces of leather in quart mason jars. This way you can rapidly speed up the process and know it will work before wasting a bunch of bark and time.

Lots of people think they know how to bark tan, but they don't. Beware amateurs and make sure to follow the techniques of old masters and manuals. We are all re-learning this old technique and many new experimenters have their own weird ways. The manuals above are the closest I've come to straight answers to any questions I could have.
 
Adam Klaus
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Nice. The idea of using sumac leaves sounds really ideal, it will be a few weeks until the sumac leafs out here, but that would be really much easier than stripping bark.

I am butchering a few bulls this week, and would like to experiment with bark tanning one of the hides.

Am I correct that I can dry the hide initially, and then rehydrate it later once I have sumac leaves available? Is there anything particular that I should know about drying the hide, to make the later process of tanning easier and better?
 
Dennis Lanigan
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Adam, I would wet salt or freeze the hide, if possible. But you can dry. The second manual has directions on how to dry but I can summarize.

1. Getting the hide off

If your butcher is doing this then you just have to make sure he/she is pulling the hide off, not cutting it off. If you are doing this than make sure to learn how to pull a hide off. Make the initial cuts around the limbs and neck, but after that DO NOT use a knife. I've field butchered a buffalo so it is possible, while super difficult, to hand pull off a large hide (the buffalo was held up by a front loader which made it easier). Use your hands or a blunt object to separate the hide from the body cavity. It is OK to use a knife if the fascia, meat, and fat are getting ridiculous -- just don't hit the hide. Having a wench can help, if you already have it.

2. Scraping the gunk (wetscrape or dryscrape)

Wetscrape: You need a scraper and a beam to get the blood, meat, fat, and fascia off the hide (these are described in the manuals). A large PVC pipe can be accommodated to use as well. You need to take all gunk off the hide asap before drying it out. Search "scraping beam" to get some ideas.

Fleshing knives: http://www.fntpost.com/Categories/Fur+Handling/Fleshing/Fleshing+Knives/ Rounded knives make fleshing A LOT easier.

[Once it is scraped you could also wet salt or freeze. Wet salting means: tacking the hide up on some plywood, raising the plywood from the ground at a slight angle at one side, and salting with feed salt. The next day a bunch of gunk was pulled out of the hide and rolled on down. Re-salt and put in a rat/mouse proof container until ready to tan. This is how all industrial tanneries preserve hides btw.]

Another option is racking the hide (see below) and scraping the gunk off with a dry scraper (Available here: http://www.braintan.com/mm5/merchant.mvc?Screen=PROD&Store_Code=1&Product_Code=DRYSCRAPER&Category_Code=Tools). This is a good idea if you want the hide kept whole and if you're good with tools. You'll need to put a bead on the blade of the scraper so it scrapes down the hide and not through it. You'll also be fighting a hide that is drying as you scrape, especially in high alt CO, so cutting through the hide as you scrape is a risk.

3. Drying it out

Like I said, the manuals cover this but I can offer some suggestions. The idea is to get the hide as stretched out as possible. You could nail, for example, four pallets together and then nail the hide (flesh down) stretched out on the pallets. The key is air flow, keeping the flesh side down (because the fat remaining in the flesh can burn in the sun), and stretching it out. People also create large frames (with 2X6s), reinforce the corners, and then lace the hide into the frame to stretch it out. Check these frames out for examples: http://paleoplanet69529.yuku.com/topic/37954/What-does-your-frame-look-like

At any point, especially with a bull hide, there is no shame in cutting the hide up into more manageable sizes. This may be necessary for tanning anyway, unless you have huge containers and lots of water.

Tannins are at the highest in Sumac leaves in September. And you'll need a lot (I can't say exactly how much because tannin levels differ per plant/season/etc). I would try other stuff like Tanner's dock/yellow dock, grape leaves -- any stuff that shows up in herbal remedies as astringent.
 
Dennis Lanigan
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OK, I'm writing more on bark tanning which is my favorite subject.

Steven Edholm is a longtime student of bark tanning and has some excellent "do nots" of here.


One of the main reasons I'm mentioning the post above is it has pictures I want to address. One picture shows score marks from a zealous butcher. This is the bane of all tanners and is why all skinners need to have their knives taken away at some point. Another picture shows a "side" of a bull hide that Steven tanned. This is a great example of cutting up hides before tanning based on expected thickness of the hide. While whole hides can be tanned, large hides are easier to tan if they are cut up based on thickness of the skin. The stomach, legs, and hind quarter areas are a lot thinner than the neck and spine area and so will tan at different rates. This matters as giving thinner leather too much tannin can waste tannin and crack the grain. In other words, if I was tanning a bull hide I would cut it up into sections like this:



And Adam, if this works out, please consider donating some sole leather (Bends, above) for to me to make some shoes. Good luck.

 
Dennis Lanigan
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Back with more. Wanted to chime in about tanning in a permaculture context.

I actually hate bark tanning, in a sense. I don't like people looking at majestic trees and thinking "Wow that'd make some awesome leather/house/lumber, etc." I can't say for sure, but I would guess whole forests of Eastern Hemlock got chewed up for tanning leather when the Eastern/New England cities demanded it. That's not sustainable in any sense. Cutting down whole trees--or windfall--on your homestead for a roundpole timberframe structure and using the bark on the side is one thing [Edit: for a long lasting super insulated house that will ultimately reduce total wood usage]. Or bucking up some windfall trees for firewood and gathering the bark before bucking. I've done that. I've gathered bark from windfall trees and from clearcuts (feller bunchers leave a lot of bark lying around). But I have never cut down a tree just to tan with it and never will. Nor do I advocate anyone cutting down trees just to use the tree's bark. I have even got tannins from "beauty bark" (in the NW beauty bark is fir/hemlock) because it's there already chopped up ready to go, but I don't think beauty bark is part of a sustainable tanning scheme.

If there is to be a future: coppicing, leaves, and roots are the future of leather tanning.

Sumac is the number one guy worth mentioning because it grows in all 48 states. But another worth mentioning for arid/dry climates is Tanner's Dock. Here's a UC Berkeley Extension report on growing Tanner's Dock. ( https://openlibrary.org/books/OL25199150M/The_canaigre_or_tanners_dock ) I have friends who gather tanner's dock in washes outside Tuscon, AZ.

Tanner's Dock seed from Horizon Herbs: https://www.horizonherbs.com/product.asp?specific=2657 (hardy to 20 F).

Coppicing schemes are of course a great option for getting bark from trees. In The Woodland Year by Ben Law he shows that people coppice oak for the bark to make "fine medical leather" (all bark tan is non-toxic so it's more likely to be used in medical contexts). Some trees that coppice well and have high tannins are birch, willow, and chestnut. I would also investigate the tannin levels of green alder. I know red alder has some tannins (and fixes nitrogen) but it doesn't coppice.

Willow of course would make an awesome multi-function coppice plant: bark for tanning, suckers for rocket stoves, suckers for baskets, branches for fencing, etc. (Not all willow makes great basket material and willows vary in tannin content based on species and location).

Here's a super strange mainstream FAO report on coppicing willow for biomass/bioenergy production. http://www.fao.org/docrep/008/a0026e/a0026e12.htm I don't advocate their scheme (edit: I support the science and experimentation, even the breeding, but not the use of heavy machinery as part of a "sustainable" scheme), but it does demonstrate that people are using willow seriously. Salix eriocephala is used, which is also high in condensed tannins.

S. eriocephala ‘Russelliana' variety is sold by Willows Vermont for basketry and living structures (but they are out of it). (And I'm sorry to tease, but most places only sell willow from Dec-March, although I gathered wild willow recently and it hadn't budded out yet).

I have even gathered doug fir bark with a willow pack basket...Rigid pack baskets made out of willow are awesome.

 
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