Over Neutralizing,,, is there such a thing?

[cyclone]

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?

[Monte]

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.

[cyclone]

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

[Monte]

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.

[Waylonfan]

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.

[Monte]

Treetops,If I were to become a vender of the same products that are available through the taxidermy supply houses , I would change the instructions .
Neutralizing a pickle is just ass backwards. I have tested and tanned with most of the products availabe. Every thing that is available is a compound mixture from some hugh ,world wide chemical company.  Most of these products were supplied to me free for evaluation between 25 and 35 years ago. There are only so many tanning agents available.  I no longer tan commercial. I have a medium size taxidermy studio of over 5000 sq ft. We still do some in house tanning and send most of it out.  All in house tanning is sulphuric acid pickle or alum pickle followed by liqua-tan. This produces the highest quality in house tan in my opinion.

Just like taxiedermy, tanning will never have an industry standard.

[Bones88]

I am your simple home tanner and I have never checked the PH on any of the 7 hides I have done over the last 9 years, I am only your hobby tanner, from what I am reading I may just be lucky but I haven't had a hair problem with any of them.

I salt it
I flesh it
I salt it again
I use water & vinegar pickle 2:1 ratio
24 hrs later rinsed well
Neutralize with 1 cup baking soda to 5 gallons water 20 mins
Rinse and mix Lutan F to tan
I go by the book, deer 13-15 hrs etc
Rinse, dry and stretch

This is a great hobby, good work for all that make a living this way.

Bones

[bill@hogheaven]

Treetops there is a second part to your rule of thumb....20-30 minutes in the solution.