I have tried a product from VanDykes called "curatan" and have much better results with beaver furs with much less work than by following the procedure below. Basically, it is the same up to the point where you remove the fur from the pickling acid and rinse them off. Instead of using chromium sulfate I place the furs fur down on a piece of cardboard and rub in the curatan liberally (like oiling the skins) and let them set until all the oil is absorbed (2 to 4 days), then I wipe off the excess oil and turn them fur up for a few days until the fur is dry. Then I put them fur down on a dry cardboard and start stretching and breaking the skin a little (10 min) each day until they are done. I found that beaver skins break with much less effort this way, but I would still use the chromium for thin skinned animals like fox. Frank.
A link that you may want to check out:
These instructions are based on my own experience and instructions from VanDykes Taxidermy Supply where I order most of my supplies from (excellent service so far).
No metal containers because they will react with the acids.
***You need a room that stays around 70 or 75 degrees F to work in ***
To get bugs out spray with bug killer in plastic bag and let sit closed for about 10 minutes.
Remove as much flesh and fat from skin as possible without damaging skin.
If skin has been dried hard rinse and soak in cool water until wet clear through (probably a full day). Add some Lysol (cap or two full) from brown bottle to stop bacteria. Bacteria make the fur come out -- experience.
Stops bacteria and makes fleshing easier, and helps set the hair.
Rub fine grain salt into skin well and liberally all over.
Fold skin and lay on incline over night to one day to drain and cure. Two days at most.
Check for and remove any remaining flesh.
Hide must be washed and completely rehydrated prior to tanning.
Plunge and wash in cold water until water remains clear.
Wash in warm water (75 to 85, but less that 95 deg.). You may use commercial Blood Release, Degreaser, and 1/2 oz. detergent. I have had good results with getting the grease out by using a little Dawn Dish Soap. Repeat until clean.
After clean rinse well in cool water and check for and remove blood stains and make sure that no degreaser or soap remains.
Tanning chemicals will set blood stains into the fur.
(Very greasy hides may need a wash and soak in degreaser for about an hour.)
Skip this step if you want the fur on and go to pickling below.
After scraping and washing the hide mix garden lime (available in garden stores) in warm water until no more will disolve. Use enough water to submerse the hide. Add a little more lime and check to see that the pH is high (between 12 and 14), check to see that the temperature of the mixture is below 70 F and then submerge and agitate the hide until thouroghly soaked. Leave the hide in the lime agitating occasionally until the fur can be pulled out easily, usually about three days. When the fur comes out easily then remove all of the fur, rinse the hide, scrape it some more to make sure no flesh or membrane remains, and then rinse it several times in cool (not warm!) water until the pH of the skin comes down to 7 or less. I test it by wiping off a mid portion of hide and rubbing pH paper on it. Then continue to pickling below.
Warning: pH above 7 and warm temperatures can ruin the skin beyond repair in my experience.
Need a pH of 2 or lower. Salt is used to prevent overswelling which would slow or prevent chemicals from entering. A little too much is better than too little. I usually add enough so that a small amount of the salt remains on the bottom and does not dissolve. Should be 40 to 45% on salinity meter. 60 to 75 deg. is a good temperature for pickling and tanning. Use non-iodized salt. Make enough to completely submerge the skins.
Use one of the following formulas:
1 oz. battery acid and 1 lb. salt per gal. of water.
(This formula is a little too dangerous for me!)
3 oz. Pickling Crystals and 1 lb. salt per gal. of water.
(I have had some poor results with this formula)
0.5 oz. (about 1 Tablespoon) Oxalic acid crystals and 3/4 to 1 lb. salt per gal. water.**
(This is my favorite formula, but is still a little dangerous--be careful)
Dissolve the chemicals in a little hot water and then add cold water to bring the temp. down.
Optional: Add Chrome Saver to the pickle; Between 1.3 and 3.2 oz. per gal.
**(For 5 gal. water add 5 TBS of Oxalic Acid and 5 lbs. salt and 1 cup Chrome Saver.)
Leave in pickle bath agitating as frequently as possible for 2 or 3 days. Make sure that the skin will hold a thumb nail print before removing from pickle bath.
Remove skin from pickle bath and remove any remaining flesh or membrane from the skin.
Add 1 lb. (2-1/3 cups) of Chromium Sulfate per 10 lbs. skin to pickle bath and mix well.
Return skin to the solution and let remain another 2 to 3 days agitating frequently (too long better than not long enough).
To test cut a thick corner and see if it is blue through. Any white streak means it needs more time. The blue color will be gone by the time you finish and the skin will be a cream color, off-white to tannish depending.
Note: You may use the chrome repeatidly as long as it stays clean with plenty of color and a low pH. I usually have two trash cans, one with chromium sulfate and the other with acid that I change more frequently. The chromium sulfate is a dangerous chemical and hazardous to the environment. Proper disposal could be a problem, but do not let it get into the watershed or ground water.
When tanning is finished remove the skin and drape it on something over night in a cool place.
If pH of skin reaches 7 the flexibility is lost, the grain cracks, and the skin stains. Probably this is the cause of rubbery feeling shrunken skin that will not break after drying. This has happened to me and I have not been able to repair the skin.
Make a solution of 4 gal. cool water and 3 oz. (6 TBS) of baking soda. I have cut out the baking soda because the rinsing alone seems to work fine.
Plunge and agitate the skin in this solution between 10 and 20 minutes.
The above neutralizing instructions should not be used with thin skinned animals like fox. Plunge and agitate in plain tap water that is cool quickly. Get the chemicals off, but get it out of the water in less than 10 minutes.
The pH in the skin should go up to 5 or 6.
Drape the skin over something for a few hours to let the chrome set in well after neutralizing.
I have had very good results using VanDykes Protal tanning oil, but Neet's Foot Oil also works. Spread the fur out skin side up and heat some oil in the microwave to near boiling (it only soaks in good if it is very warm and it cools quickly). With your rubber gloves on, rub the oil into the skin. After it soaks in then rub some more oil in (reheat if necessary) until the skin is thouroghly oiled. Note: The odor is very strong the first few days! My wife dosen't like me to do this in the house because of the smell of the tanning oil.
Turn the fur up or out and let it lay or hang until the fur is nearly dry then turn the skin side up/out. I usually lay beaver furs skin down on clean (no print) cardboard and hang fox skins fur out in our entry way. When the fur is almost dry I turn the skin to the air to let it start drying.
After the fur is nearly dry start checking the skin every once in awhile by pulling on a edge to see if it turns white or light color. That is the sign that it is ready to break and if you wait much longer it will get stiff and difficult to break. This is where the real work starts on a thick skin like beaver or large one like caribou.
Tease and pull in different directions any part that turns white two or three times a day until the skin has completely dried out. You may want to twist in different dirrections and/or rub it over the end of a 2x4. Sometimes I put on my tennis shoes and use my feet to pull and stretch it. The more you work it during this part of the process the softer it will get. I have found that adding more oil makes more of a mess than helping to sofen the skin.
Sand down the dry skin until it has a nice texture and off-white color.
Fluff up the fur and it is done!!! If you let it hang around for a week or two the smell of the tanning oil will dissappear.
Note: If it gets too dry before you break it then you can soak it in warm water for an hour or so, ring it out, oil it, and let it dry again.
If you are going to make some garments from your fur I recommend that you try to find someone with experience sewing furs. It is not difficult, but there are some techniques that are much easier to show than explain.
Good luck with your tanning project.
PS (update for 2004). For me fox are the easiest to tan, but just make sure you wash the chrome off quickly with cool water because the pH rises quickly in those thin skins. I now tumble my fox furs using an old dryer. I removed the heating element and all of the wiring and, with some trial and error along with various advice, I was able to wire the motor to run on 110V and divert the fan to blow back on the motor to keep it cool. I made a large canvas bag (put the seams out) and fill it about a quarter full of sawdust. Put the fur (I only do one at a time) in the bag fur side out after oiling, duct tape it shut, and let tumble for 5 to 8 hours. This makes the furs look and smell very nice. I take them out and hang them up and work on them a little each day until the skin is dry and soft. This has been working very well for fox -- just like a professional tannery.
Beaver are difficult and a lot of physical work. I purchased a fleshing machine (the small model) from VanDykes, but it takes some skill to use well that I am still trying to develop. I am hoping that I will be able to shave the thick parts down enough to make them come out softer and more flexable.
Muskrats! My advice is to dry them and sell them to the fur buyer. I cannot seem to get good results from muskrats even though I really like the furs. It is that tough tendonous kind of flesh that I cannot get off without making holes and cannot leave on and get a good tan. If you are an expert reading this for entertainment purposes please feel free to send me some advice on fleshing muskrats (firstname.lastname@example.org).
I still have my chrome solution. I try to keep it clean so that it can be refreshed with chrome, salt, acid, and water as necessary. I do not know of any environmentally safe way to dispose of it.