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Taxidermy.Net Forum  |  Taxidermy Discussion Categories  |  Tanning  |  Topic: Over Neutralizing,,, is there such a thing? « previous next »
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Author Topic: Over Neutralizing,,, is there such a thing?  (Read 2196 times)
Waylonfan
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« on: December 14, 2008, 11:34:53 AM »

I read this in a thread in deer heads, that you could over neutralize a cape or hide and wondered if this was true, or is it a myth like we still need to eat fish on Friday.
Anyone done an actual test in the lab to prove this theory?
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Orion Taxidermy
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Marty Silva

« Reply #1 on: December 14, 2008, 12:24:26 PM »

I am by no means an expert at tanning but I think one of the ways they make a hair off leather is by giving it a bath in lye which is just the opposite of an acid hence the over neutralization. 

Marty
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cyclone
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« Reply #2 on: December 14, 2008, 04:00:38 PM »

Not a theory, it is fact...Soak a hide in base too long and you end up with a pile of goo...
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Baking soda is sodium bicarbonate. They are one and the same...

Re-hydrate! It is an important step.


Spell chek.....not jest enother perty button.
Glen Conley
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KARMA GOOSE R.I.P. 2006-2006

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« Reply #3 on: December 14, 2008, 08:04:19 PM »

It ain't no wonder why the illegals don't want to learn the English language.  I heard, and understood you loud and clear, Treetops.  You're an American, aren't you?  Always remember, you live in a country full of hot water heaters.

neutralize

 neutralized, neutralizing, neutralizes
1. To make neutral.
2. To counterbalance or counteract the effect of; render ineffective.
3. To declare neutral and therefore inviolable during a war.
4. Chemistry
a. To make (a solution) neutral.
b. To cause (an acid or base) to undergo neutralization.
5. Medicine To counteract the effect of (a drug or toxin).
6. Slang To remove as a threat, especially by killing.

neutralize or -ise
Verb
[-izing, -ized] or -ising, -ised
1. to make electrically or chemically neutral
2. to make ineffective by counteracting
3. to make (a country) neutral by international agreement: the great powers neutralized Belgium in the 19th century
neutralization
-isation n

neutralize
To cause an acidic solution to become neutral by adding a base to it or to cause a basic solution to become neutral by adding an acid to it. Salt and water are usually formed in the process.

basify
tr.v. basified, basifying, basifies Chemistry
1. To convert into a base.
2. To make alkaline.

Verb 1. basify - turn basic and less acidic; "the solution alkalized"
Caustic
caustic Pronunciation: \ˈkȯs-tik\ Function: adjective Etymology: Latin causticus, from Greek kaustikos, from kaiein to burn Date: 14th century
1 : capable of destroying or eating away by chemical action :   corrosive
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Glen Conley
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« Reply #4 on: December 14, 2008, 08:15:20 PM »

Marty, you might not be an expert, and neither am I, but what you said makes a whole lot of sense!

Glen, and Cyclone, might be a little more able, to get down, to the actual chemistry involved, but my belief, is that alot more depends on what you are neutralising with, than the Ph reached.

The neutralising Ph, is of great importance, but a chemical as simple as soda ash(sodium carbonate), can cause big problems to hair, when added to  water. A Ph of 9, using baking soda, is a different animal, than a solution, with the same Ph, using soda ash. When neutralising hair-on skins, anything other than sodium bicarbonate, is dangerous to hair, and is VERY risky!  Soda ash, is a helpful tool, in quite a few tannerys, during the tanning process. But not by itself! Thats about all I can say about that.

P.S. a little example of what I am talking about. Nair, a product used to remove hair off Ladies legs, contains a VERY small amount of Sodium Hydroxide(a very strong base), yet doesnt harm the skin. I wouldnt think the Ph of the product, is that high either?

You could take a pound of baking soda, add a little water, and make a paste, rub it on your arm, let it set, and rinse it off. Even though its Ph is probablly higher than the Nair, I suspect, you wont get any hair loss?

Baking soda (sodium bicarbonate), and sodium carbonate are in the carbonate form.  Either one can be converted to sodium hydroxide by heating in water to temperatures over 140 degrees.

Let's just say we are going to neutralize hydrochloric acid.  What we are going to do is turn the hydrochloric acid into it's salt form.  We add sodium bicarbonate to the hydrochloric acid and it reacts to form sodium chloride as it's end product.  The balance of the carbon, oxygen, and hydrogen are given up as carbon dioxide and water.

What would be produced by adding hydrochloric acid to sodium hydroxide?
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Monte
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« Reply #5 on: December 15, 2008, 10:11:51 AM »

Hair removal in the leather industry is done in most part with hydrate lime and sodium sulphide. The wet drum run time is aprox. 1.5 hr. on deer and 2 hr. on cow or buffalo.

Note; I still do not agree with neutralizing a pickle before the tan goes in. Neut. the pickle is sure to over neut. some sections of the skin rendering the tan useless.
While some achieve results they are happy with by neut. the pickle it is not a sound practice.
If the pH of the skin is above the precipatation point of the tan , How can this work unless a suitable buffer is used and I have not seen any home tans selling a buffer with their kits or products.
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Monte
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« Reply #6 on: December 15, 2008, 02:12:39 PM »

Hudson ,The short answer is While leaving the skins in the pickle , hair-on or leather ,after determining that the pH in the pickle is what I want checked on the thickness of the skin , then the tanning agent and the buffering agaent is disolved and fed into the drum, paddle , or static vat while stirring, this can take from 3-24 hours depending on the tan agent used. I use the buffer agent to get a greater degree of tan by raising the precipatation point of the tanning agent while not giving up stretch. Regardless of the tan agent used , the tan agent and the buffer agent are fed into the pickle and slowly raised to the finished  pH. All the time I have now, more later.
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Monte
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« Reply #7 on: December 15, 2008, 06:32:52 PM »

oldshaver, I agree,I would never use soda ash, pH is not predictable and to difficult to maintain consistency. I don't think it would make a reliable buffer.
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Waylonfan
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« Reply #8 on: December 15, 2008, 07:17:40 PM »

Soooooo,, one tablespoon of baking soda per gallon of water,,,, who came up with that rule of thumb as the standard for neutralizing a home tan, and what would two tablespoons of baking soda per gallon do? Wouldn't that be considered over neutralizing?
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Glen Conley
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« Reply #9 on: December 15, 2008, 07:47:20 PM »

Soooooo,, one tablespoon of baking soda per gallon of water,,,, who came up with that rule of thumb as the standard for neutralizing a home tan, and what would two tablespoons of baking soda per gallon do? Wouldn't that be considered over neutralizing?

I can't remember the kid's name.  It was Joe, or Johnny, or Billy, or something.

Here's a short article you might find useful.

WATER AIN'T WATER!
www.taxidermy.net/forums/TanningArticles/02/l/02A3D078C7.html
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cyclone
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« Reply #10 on: December 15, 2008, 08:50:08 PM »

Soooooo,, one tablespoon of baking soda per gallon of water,,,, who came up with that rule of thumb as the standard for neutralizing a home tan, and what would two tablespoons of baking soda per gallon do? Wouldn't that be considered over neutralizing?

You could put a truckload of bicarb in the solution and it wouldn't hurt the hide IF(notice the if) you monitor the pH within the hide.  When it gets to the desired pH...Pull and rinse..

When you put sodium bicarbonate or sodium carbonate in solution,  the carbonate or bicarbonate ion have the ability to pull a proton (H+), hydrogen ion or the ion that causes acidity off of a water molecule.

H-O-H(water) ------>  OH-(hydroxide)...The hydroxide is formed..  (no the equation isn't balanced)

Soda ash, sodium carbonate is a salt.  It can pull two hydrogen ions of of two water molecules forming two base or hydroxide units.

Sodium bicarbonate, baking soda, can pull one hydrogen ion off of a water molecule...It can also donate one hydrogen...


Baking soda is an acid salt.  It has a hydrogen ion that it can donate as well...It can act as a base.  It can act as an acid...It makes a most versatile buffer solution..


Now with all that being said, doubling the amount of baking soda isn't going to hurt a thing if you monitor the pH properly....

                                                                            (You did notice the if...) right?
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Baking soda is sodium bicarbonate. They are one and the same...

Re-hydrate! It is an important step.


Spell chek.....not jest enother perty button.
Monte
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Location: Drexel, Mo
Posts: 725

« Reply #11 on: December 16, 2008, 08:36:28 AM »

cyclone, your big IF is most important. I don't think it is likely that the adverage home tanner has the skills to monitor the pH through the thickness of the skin.  The brisket and the skin on the back of the neck are of great difference. The risk of damaging the thinner parts of the skin is evident by a lot of folks on here explanning the hair loss on the lower end of the cape where it is thinner.
It is much safer to neutralize after the tan has penatrated the skin thickness in the thicker areas and over a longer period of time than to neutralize the pickle. How can you fix the tanning agent any other way without guessing.  My tanning experience on hair-on and leather spans over 40 years and I have made every mistake you can imagine.
The fixation point of all the different tans is a different pH.
Aluminum sulphate--4.2, buffered  5.2 anything higher will ruin the tan. Note; the carbonates will not work for buffering the  alum tans.
syntans- vary from 4-5.5 and never really stop tanning in this range ( they were invented to replace veg. tans when bark was hard to get from abroad in the early 1900's. 
Chrome 4.2  to 6.8
This covers most of whats availabe to taxidermist. Aldahydes and veg. tans are not significant to the home tanner. enzyme (brain) is almost entirly a home process.
Oil or chamios tanning is hard to control and of no sigifance to the home tanner. When properly done makes the best hair-on skin you will have your hands on and cost more to do.
The info I have provided is just food for thought.
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cyclone
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« Reply #12 on: December 16, 2008, 10:33:39 AM »

Soooooo,, one tablespoon of baking soda per gallon of water,,,, who came up with that rule of thumb as the standard for neutralizing a home tan, and what would two tablespoons of baking soda per gallon do? Wouldn't that be considered over neutralizing?


Much like me, he is a bucket tanner Monte.  The one tablespoon recipe had to come from the marketer of a  home kit trying to put steadfast directions on the process.

Would 1 Tlbs/gallon work on a bison hide, elk or moose hide?  How about a mouse?

I'm sure that tanneries use recipes for large batches that ensure success.  I'm sure that you wouldn't consider the pH "adjusted" immediately after just adding X amount of base...It takes time to react with the acid in the solution as well as the acid within the hide itself.  It is not instantaneous.

Deja Vu...didn't we have this discussion before?  http://www.taxidermy.net/forum/index.php/topic,26754.0.html
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Baking soda is sodium bicarbonate. They are one and the same...

Re-hydrate! It is an important step.


Spell chek.....not jest enother perty button.
Monte
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Location: Drexel, Mo
Posts: 725

« Reply #13 on: December 16, 2008, 11:00:20 AM »

I am sure we did. The questions keep on comming. However , I do enjoy discussing tanning . Any kind
Also I work off percentages of hide weight.
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Waylonfan
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Posts: 108


« Reply #14 on: December 16, 2008, 07:43:04 PM »

Sooooooo,,, Monte,,, You paid your dues and learned your lessons, why would vendors to home tans recommend to neutralize before tanning? And you firmly believe in neutralizing a tanned skin, what would it take for your theory to become the industry standard vs. the current paradigm?

Glen,, I heard that preach'n before, was baptized in soft water of neutrail pH.
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