Author Topic: Mixing Nitric Acid  (Read 10103 times)

George F.

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Mixing Nitric Acid
« on: September 10, 2008, 01:20:09 AM »
What exactly is the proper method of making nitrate of iron? When do you mix the water with the acid and how, and in what proportions, and when do you add the iron and how much?

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Re: Mixing Nitric Acid
« Reply #1 on: September 10, 2008, 02:29:32 AM »
Not sure about the proportions, but always add the acid to the water, not the other way around.  It has a nasty way of spitting and splattering if you add the water to the acid, which can be quite hard on eyes.

Brian

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Re: Mixing Nitric Acid
« Reply #2 on: September 10, 2008, 02:50:04 AM »
I am in the process of moving the archives to this board, but here is some info that might help you:  It is from Mr. Young of Wahkon Bay Co (2 posts).  The second paragraph gives his formula.  Hope this helps:

Let me clear up the additive questions here:  Pure nitric acid will not dissolve the iron needed for the stain, so one must add some ""excess portons"", either in form of another acid, or just plain water, either distilled water or tap-water, it makes no difference, I always used concentrated (10.5 molar) hydrochloric acid (aka, Muriatic acid), mixed with the concentrated (15.0 molar) HNO3, into which I introduced iron in the form of 4d finish nails.  The resultant product, a matrix of very acidic, aqueous ferric nitrate and ferric choride, would be a dark, reddish liquid, which is very strong at this point, too strong for personal safety.  (If you add only water for the excess protons, the products will be only the acidic, aqueous ferric nitrate.) I diluted take this liquid to a 40% solution, or 1 1/2 parts water, to one part product.  This dilution is not critical, either, as this dilution factor was merely arrived at a compromise between reactivity performance (strength of solution) and shipping/customer safety.  I always used a radiant heat source, paint-peeler, or heat-gun, which functions much better than a direct flame heat source, held fairly low (like about 2"") from the wood's surface, but always kept the heat-gun moving, so not to scorch the stock's high areas.  The results were always favorable to my eye, but different woods, species of maple, red, sugar, or silver (yuck!), different densities, etc would produce varying results to a degree.  I always neutalized with one application of a cotton swab dipped into a solution of sodium bicarbonate (Arm & Hammer), or the stock's tone will deepen (darken) over time.  I made and sold untold thousands of bottles of this product over the past 25 years, until supply problems caused me to cease the trade this past year.  William Young, Wahkon Bay Co



To respond, shelf-life is not problem, if kept in the amber containers.  Best to store in cool, dark place tho, like a basement pantry or cupboard.

LMF, et al. stains, are dyes, and I have some issues with stabiltiy of some dyes, as they fade out from U-V radiation, the typical shoe leather dyes are good examples.  On my Whitmore-style silhouette rifle, I ""ebonized"" the stick with Fiebing's black leather dye, which appears to  initially stain dark and deep, but must be ""refreshed"" every year or so to keep it from fading, quite a contast on this wood between the upper ramrod and the lower part within the stock!!

Yes, I often add LMF Walnut (not American Walnut) or mix of LMF walnut/cherry over the AQ treatment for added reddish undertones, if desired.  Remember, the AQ will continue to react over time with U-V, but rather than fading, it darkens, so it should be ""neutralized"" after application, unless one desires the dark, aged look.  With some very hard, straight grain, sugar maple stockwood, I do not neutralize as I desire it to darken as initial response to AQ is not as dramatic as on curly, red maple...

The browning/bluing formula I extracted many years ago from a book written by A.O. Zischang, it is easy to make, given the oxidants, a suitable, heat-tolerant container and open-space or ventilation from which to escape the copious amounts of liberated NO2 gas.  I made the stuff in large batches in a large (50 liter) HDPE container, but one can whittle the proportions down to managable size and make enough browner/bluer to last a couple smiths their lifetimes. 

So, here we go... 300 ml (10 fl-oz) of conc HNO3 (15-16 Molar), 240 ml (8 fl-oz.) of conc. HCl (10.5-12 Molar), mix the acids, in large, heat-tolerant container, add about 30 grams (~2 oz.) of 4d finish nails, do this outside, depart the immediate premises and allow the iron to dissolve, liberating NO2 gas, very dangerous, so get out of there, and isolate the system from any metal objects you care for!!  Let this exothermic, almost volcanic, reaction occur, allow to cool, then with dionized or distilled water, dilute this matrix to one gallon, or about 3784 ml, total solution.  Store final product in amber glass or polyethelene container.  This will give you enough browner FOREVER.  To make the AQ stain, follow same procedure, except after reaction has ceased, dilute to only about one-third, or to about 1200 ml (~40 fl-oz) of total product or solution.  Now, if you are only interested in creating a stock reagent, then one can approach it by taking only the conc. nitric acid, diluting about 2 or 3 to one with water, by adding acid to the water, NEVER, the reverse, and adding degreased steel wool to the acid solution until no more appears to react, then use it for final product in that state of dilution.  Pure nitric acid will not dissolve the iron, it must have ""excess protons"" within the system, whether from another acid, like the HCl, we cited, or from the water, which obviously need not be that pure, as we need H+ ions, not water molecules...

That's the story, not bioengineering or rocket science, but be careful if you undertake this project, as the NO2 is dangerous, noxious, toxic, and some say even carcenogenic...  Wear eye protection and rubber gloves when handling any strong oxidants, safety first, stock stain/barrel- browner second!!




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Re: Mixing Nitric Acid
« Reply #3 on: September 10, 2008, 04:19:23 AM »
The safe, cheap, and easy way of making the stuff is to use Ferric Nitrate (which is what you get after the acid and iron):  You just dissolve it in water and you are good to go.  But this is probably opening a can of worms.

Brian

Offline Dphariss

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Re: Mixing Nitric Acid
« Reply #4 on: September 10, 2008, 04:26:04 AM »
Mixing in Hydrochloric in might be OK for the guy making it but straight nitric cut with water does a much better job of making a stain. I am told that Hydrochloric muddies the color. I would have to agree based on experience.
I now make my own AF stain with only Nitric and water and like it a LOT better. Gives crisper color IMO.

I would cut the nitric 50-50 or even a little more with water, assuming you have high grade nitric. I use a stoneware pitcher or other stoneware container.
I add degreased steel wool or small nails until the acid is nearly depleted or even completely depleted. Note that initially there will be a lot of nasty brown fumes created and a fairly violent reaction until the acid is somewhat depleted.
Be careful. The stuff can cause great bodily harm or death. Use protection and keep water for washing handy. Avoid the fumes and do this OUTSIDE.

This rifle was stained with a Nitric stain made as I describe above so it really does work. I believe that it compares favorably with an original JP Beck that was pictured on the old site.
This Nitric is very strong and is in its original shipping bottle.
This stain works great on Oak as well BTW.
Dan
« Last Edit: September 10, 2008, 04:46:49 PM by Dphariss »
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Re: Mixing Nitric Acid
« Reply #5 on: September 10, 2008, 04:28:30 AM »
The safe, cheap, and easy way of making the stuff is to use Ferric Nitrate (which is what you get after the acid and iron):  You just dissolve it in water and you are good to go.  But this is probably opening a can of worms.

Brian

Should work fine but I was given a lifetime supply of nitric some years ago.
The "active ingredient" IS ferric nitrate.

Dan
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ironwolf

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Re: Mixing Nitric Acid
« Reply #6 on: September 10, 2008, 12:08:51 PM »
  I have to agree with Dan.  Stay away from the HCL.
   I use 70% Nitric watered down to around 7:1 or 8:1.  If you make the dilution before adding the Iron, the reaction won't be as severe due to the weakness of the solution.

  KW

Offline Long John

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Re: Mixing Nitric Acid
« Reply #7 on: September 10, 2008, 04:22:32 PM »
Keep in mind that the color that resides in the stock is NOT ferric nitrate.  It is a mixture of ferrous, ferric and ferrosoferric oxides that impart a blackish-brown, reddish orange and reddish brown color, respectively.  The stock stain is effectively a solution of ferric nitrate and, if you use hydrochloric acid, ferric chloride.  When you apply heat the nitrate part of the ferric nitrate finds a hydrogen atom somewhere (there is lots of them in wood) and boils off, leaving the iron (ferric or ferrous) ions left over.  They snatch oxygen atoms from the air and turn the color we expect from a mixture of iron oxides.  No heat no color and neutralization is recommended.  Ferric chloride is a blackish brown.  Heating will cause ferric chloride to also transition to hydrogen chloride gas leaving behind iron oxide.

If you want to avoid the hazards of dealing with strong acids then don't.  Use vinegar instead.  If you use vinegar the reaction will take weeks, not minutes but you will get iron acetate solution.  When exposed to air (no heat necessary) the acetate ion evaporates leaving the iron oxides behind.  Regardless of the method you use to get the iron ions into the wood the final stain is actually a mixture of iron oxides.

The stain I used for my Bucks County squirrel rifle was made from old barbed wire dropped into a crock of cider vinegar.  It has been sitting on the shelf for almost 20 years.  No heating nor neutralization requred.  And every colonial farm had apple trees for making vinegar as pickling was a principal way of preserving food.

Best Regards,

John Cholin

Offline Acer Saccharum

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Re: Mixing Nitric Acid
« Reply #8 on: September 10, 2008, 09:18:56 PM »
use vinegar.......

And Iron.......

And join the Bretheren of the Vinegar Stain.

Acer
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Offline T*O*F

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Re: Mixing Nitric Acid
« Reply #9 on: September 10, 2008, 11:00:34 PM »
Quote
If you use vinegar the reaction will take weeks, not minutes


Salad vinegar is a 5% solution.  Does anyone know the difference in boiling points between water and acetic acid?  It might be possible to heat the vinegar and evaporate off some of the water.  This would concentrate it to a stronger solution and probably work faster.

Another slow reacting stain is plug tobacco in household ammonia.
I found the results to be about equivalent.
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George F.

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Re: Mixing Nitric Acid
« Reply #10 on: September 10, 2008, 11:10:05 PM »
I have tried apple cider vinegar on a pistol stock, another project sitting in limbo on the bench almost completed. It turned out okay, I would like to give the nitric acid and iron a go. I seen some beautiful work using it and thought I"d try it again. The last time I tried it I put some brads in the acid but didn't mix it with any water. Not having studied chemistry in H.S. I can see was a mistake now 40 years later.   ...Geo.

Offline Long John

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Re: Mixing Nitric Acid
« Reply #11 on: September 11, 2008, 04:56:56 PM »
TOF,

The boiling temperature of acetic acid is 117.9 C or 178 F.  I suppose in theory your idea would work.  I have never tried it.  You can also purchase "glacial acetic acid" from a chemical supply outlet which is a concentrated form of acetic acid.  You will then have to add water as all acids actually work by ionizing water.  Nitric acid is HNO3.  When mixed with water the hydrogen (H)+ parts from the nitrate (NO3)- causing the hydrogen (actually just the hydrogen nucleus because the electron stays with the nitrate ion) to form a hydronium ion H3O.  Its the hydronium ion that actually does the work.

The only thing using nitric acid gains you is time.  If you plan to use an iron oxide stain then start the stain when you start letting in the barrel.  By the time you are finished and ready to stain the rifle the stain will be ready to use.

On the Bucks County rifle I took about 1/4 cup of my stain mixture and mixed it with about 1/2 a cup of white cider vinegar that I got at Shoprite for $0.39.  I added vinegar because I wanted a more reddish color than I was getting with straight stain.  The straight stain was giving me a darker brownish, almost walnut color.  That meant there was too much ferrous ion and not enough ferric ion in the solution.  By diluting the iron and increasing the acetate I pushed the reaction to the red end of the color range.  I applied to coats of stain, rubbing the stock down with de-oiled steel wool and a hemp brush after each coat dried and no longer smelled like vinegar.  this is what I got.





When it stops smelling like salad the vinegar has evaporated away and all of the iron in the solution has converted to iron oxide.  No pain, no strain, no toxic fumes, no hassle.  And the reality is that the iron ions don't know how they got that way, there is no difference between the iron oxide produced with acetic acid versus nitric acid except that it took longer to make iron ions with the acetic acid.

Best Regards,

John Cholin

« Last Edit: September 11, 2008, 05:17:07 PM by Long John »

Offline Dphariss

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Re: Mixing Nitric Acid
« Reply #12 on: September 11, 2008, 05:29:49 PM »
So there is not left over acid in the wood when the vinegar evaporates?? Acid is acid some are just slower acting than others if I am correctly informed. But then I am no chemist.

Dan
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Offline Long John

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Re: Mixing Nitric Acid
« Reply #13 on: September 12, 2008, 03:15:03 AM »
Dan,

Nope!  If you can't smell it in the stock there isn't any left.  Acetic acid has a high vapor pressure at room temperature and will leave almost as fast as the water.  No heat necessary.  No neutralizing necessary. 

And, I did major in chemistry when I attended college.

Best Regards,

John Cholin

Offline Dphariss

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Re: Mixing Nitric Acid
« Reply #14 on: September 12, 2008, 07:52:07 AM »
Dan,

Nope!  If you can't smell it in the stock there isn't any left.  Acetic acid has a high vapor pressure at room temperature and will leave almost as fast as the water.  No heat necessary.  No neutralizing necessary. 

And, I did major in chemistry when I attended college.

Best Regards,

John Cholin

You seemed to know what you were saying.
Dan
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