Skin Tanning? What’s Involved?

Right so you’ve shot that bull or buck you’ve been trying to get for years, but now what? How do you preserve it so you can enjoy its presence over numerous glasses of red by the fire?

We are lucky enough to have such a variety of game in New Zealand, and a skin as a floor rug or a wall piece really is a large part of the “trophy”.  Winter coats and summer coats can look awesome depending on the time of the year, everything from Tahr, Chamois, Red deer, Fallow deer you name it.

Adam Cowie from Animal Skin Tanning Services is the guy you need to talk to, with over 20 years’ experience he’s the guy that can make that skin last and finally give you back that freezer space that the wife’s been hassling you about.  Adam gives us some insight into the different processes and what’s involved from doing it yourself through to the professional service he provides.

 Using the toggle frames

Using the toggle frames

Here at Animal Skin Tanning Services Ltd we contract tan all sorts of skins and hides from rabbits through to cow hides and everything in between for anyone who would like a professional finish on their precious animal skin.  I have been working in the tanning industry 30 years and have a diploma in tanning technology and an advanced certificate in dyeing of skins. Previously I was the Technical Manager at a tannery in Southland for over 15 years and have for the past 7 years been running my current business Animal Skin Tanning Services

 There are many ways to tan or cure an animal skin ranging from the very basic to the very complex.

Firstly though, what do you do with your animal skin once the animal is dead? It is vital that bacteria doesn’t get a hold of the skin and start the process of degradation as this will only result in hair loss during the tanning process. 

While the skin is still on the carcass there is little chance of bacteria getting hold. That said though, try and keep the animal in a cool dry place, don’t leave it out in the hot sun. Once it is flayed (skinned) you have two options.

One is to salt it down thoroughly, to do this you will need to ensure the flesh side is clean and free of any fat or meat. Then typically apply for example to a deer skin 4-5kgs of ordinary salt (Iodised or not it doesn’t matter).  Salt is there to stop the bacterial action getting started and nothing else. Once you have salted it leave it somewhere cool where it can drain, as the salt will draw the moisture out of the skin. Once reasonably dry it can be stored until ready for tanning, again a cool dry place is ideal.

The second option is to freeze it, once you’ve skinned it out hose it down with cold water and leave it to drain off. Then roll it up hair in or hair out (either way is fine) and place it in to a bag and then your freezer.

Obviously if you’re out hunting for a few days salting is going to be the obvious option, so take 5kgs of salt with you so you are prepared. As a side note, don’t salt possums and rabbits as they will still tend to lose fur. They should be frozen or air dried on boards.

 Processing drums

Processing drums

Tanning methods vary depending on what the final product is to be used for.  The most basic is using kerosene and baking soda to degrease and dry the skin out. Technically there is no actual tanning taking place with this method, you are really just drying the skin out.   It is the same as simply salting the skin, and with either method if the skin was to get wet it would then begin to rot.

 

Tanning involves using certain chemicals under certain conditions to crosslink the collagen fibres through various types of chemical bonding to change the raw pelt into a leather that will not rot, if it gets wet and is immune to being broken down by bacteria.  It also has thermal stability, so can be washed or dry-cleaned if necessary. 

Vege tanning is another method used primarily on heavy leathers such as belting, shoe soles and harness leathers.  This method produces quite a stiff result, which for these leathers is necessary.   The tannins of certain tree barks go through a chemical process to enable them to become more effective as a tanning agent.   I’ve heard people say this type of tannage is all natural and no chemicals are used, however this is not true.  You still have to use chemicals in the stages prior to vege tanning, and the vege tanning agent itself is chemically treated to enable it to work.

Alum which is aluminium tri-formate is used primarily by Taxidermists as it gives a soft result with plenty of stretch.   Obviously this is pretty key for mounting capes onto forms.  It can be used on flat skins for floor rugs also. There are some downsides with using alum, and that is if you were to wash the skin some of the alum will wash out.   It is not bonded strongly enough to stay within the skin meaning when your drying out the skin again it can end up quite hard and cracky.

The preferred method of tanning that we use in our factory is chrome tanning, with the main chemical being tri -valent chromium sulphate.   This method of tanning is probably used in 80% of the world’s leathers.  This is because it is without doubt the most versatile method and gives many outstanding properties needed for leathers. Skins tanned this way will not rot, will not breakdown due to bacteria, and can be washed or dry cleaned yet remain supple.  They also hold the hair in extremely well, ensuring the skin will not shed over time.  This is due to the strong bonds that are formed in the tanning process.

There are many stages the skin has to go through to achieve a good result.   We begin by soaking,   where we use a detergent and bactericide which rehydrates the skin and kills any bacteria present.   Fleshing is next  to remove any remaining fat and meat off the skin,  then scouring and degreasing to draw out any grease and fat from within the skin that will impede the tanning process.  This is followed by pickling in salt and acid brine, then onto the tan bath using the chemicals outlined above.   After all this we start on buffing of the flesh side and sometimes shaving depending on the type of skin being done.   Next on list is oiling using an emulsion of natural and synthetic oils in water, followed by drying, buffing, staking to soften, then brushing and trimming again depending on what type of skin is being done.

Having the right machinery for the job not only makes a big difference in time and effort, but also has a huge bearing on the quality of the end result.  As can be seen in our photos we have a fully equipped tannery with all the machinery necessary for a professional job on your hard earned skin.

However we do understand the desire some people have to do it themselves, so we also sell tanning kits with everything you need.  The kits have all the chemicals needed except salt, as well as written instructions, a DVD and safety gear.  It follows the same stages as detailed above and will achieve a good result.  These can be purchased on our website www.animalskintanningservices.co.nz

Editors note -

Here at PointsSouth we have used Adam for a heap of skins now, the result is always great and the turn around time is mind blowing.  So get those skins out of the freezer and get in touch with him, full details are available on his website.

www.animalskintanningservices.co.nz.