Nitric Acid question

[Shreckmeister]

I note the main ingredient of plum brown barrel finish is nitric acid.  Can this be used
to dissolve steel wool and make finish or do the other ingredients in the plum brown
make this a bad idea?

[Bill of the 45th]

Rob, I've used it for both A?F stain, and for browning in the past.   It worked but it's better to get a bottle of each for their intended purpose.  I now use ferric Nitrate  for browning, and staining.  In my opinion the Wahkon Bay products work the best, and easiest.  If you want to try it, get some scraps of maple, and barrel, and practice.

Bill

[Shreckmeister]

Bill,  Is the ferric nitrate as costly to buy?  What kind of a color does it produce versus the Nitric Acid?
If the color is very similar, I might give it a try.

[Dphariss]

I note the main ingredient of plum brown barrel finish is nitric acid.  Can this be used
to dissolve steel wool and make finish or do the other ingredients in the plum brown
make this a bad idea?

Bad idea.
Get some Ferric Nitrate crytals or nitric acid.
Dan

[Dphariss]

Bill,  Is the ferric nitrate as costly to buy?  What kind of a color does it produce versus the Nitric Acid?
If the color is very similar, I might give it a try.

According to tests done by a friend the color is identical between Ferric Nitrate crystals and stain made with acid on the same piece of wood.
The IRON in solution is the stain.

Dan

[Joe S]

Ferric nitrate is cheap.  Here’s a link for 100g for $10.95.  That’s enough to last for many guns.

If you dissolve iron in nitric acid, you get ferric nitrate. The main difference between the ferric nitrate crystals you buy and ferric nitrate that you make is that homemade ferric nitrate is in solution in water, and with the crystals, you have to add some water.

If you wnat to be totally PC, you can make your own ferric nitrate (or as we say here, aqua fortis).  This is an expensive and somewhat dangerous procedure.  Like Dan, I can’t see any reason for the average builder to do this. 

Aqua fortis is used as a wood stain.  Historically, barrels were browned with dilute nitric acid, and many other chemical compounds as well.  Ferric nitrate is an oxidizing agent, so I suppose it could be used to brown barrels.  I’ve never tried it, so I don’t know how effective it would be. 

You can get nitric acid for browning if you want to.  The nitric acid isn’t especially expensive, but since it’s a hazardous material, the shipping is quite expensive.  You’re looking at something like $75-$100 to get some nitric acid.  Again, unless you know how to handle strong acids, you’re a lot better off using commercial products.

[Shreckmeister]

Dan/Joe,  Much appreciated.  I just ordered 500 g of ferric nitrate crystals for $33 from Sciencecompany.com.
That included shipping.  The cost of 500 ml of nitric acid was over $100 shipped (plus I would probably end up on some govt watch list).   I don't know how many
ml of solution will be yielded by 500 g of crystal, but I'm guessing it's more than 500 ml.  Do I dissolve
the crystals to the saturation point of the water at room temp or is there some formula to use?  Do I need
goggles, a motorcycle helmet and plastic suit to mix this stuff?  I'm going with the goggles no matter what.

[Joe S]

Ooops – forgot the link http://secure.sciencecompany.com/-P6384C670.aspx

But, you seem to have found it anyway.

It’s been a while since I did anything with the ferric nitrate crystals, but as I recall, about 4-5 parts water to one part crystals would be a good place to start.  Goggles are always a good idea, but other than that, ferric nitrate is reasonably safe and easy to deal with.  The concentration is not real critical.  If you want a darker color than what you get after the first application, you can always put on another coat.  Here’s something else from Mad Monk to keep in mind:

http://americanlongrifles.org/forum/index.php?topic=3676.0

The iron does indeed care how it got there when it comes to the range of colors produced on the wood. The color array is a function of a number of factors. When you stain the wood you are creating minute particles of the iron as an oxide… on the wood. If you simply convert the stain with a little heat you get one range of colors. If you continue heating or heat at a higher temperature you get other colors………

The color of iron oxide will change with the number of molecules of water attached to each molecule of iron oxide. Generally, a yellow oxide will have 7 or 8 molecules of water attached to each molecule of iron oxide. Drive off some of this and you get brown. Heat very hot to drive it all off and you get a red iron oxide.

[Meteorman]

some folks dissolve the crystals in water, some use denatured alcohol.
I use the latter. 
My recipe is 1 part ferric nitrate crystals dissolved in 2 parts denatured alcohol, by volume.
The thinking is that using denatured alcohol will raise the grain less, altho I can't verify that with any real data.
The alcohol does dry faster.
Give 'em both a test and see what you think.
I doubt there's any noticeable color difference between the two.
I agree with Dan  - it's the iron doing the coloring, not the liquid medium.
Keep it tightly capped, or every steel tool in the vicinity will develop a light coat of rust.

I have noticed this: the water-based solution stays in solution -- the alcohol-based solution ends up with a heavy yellow-orange precipitate in the bottom of the jar after 8-12 months  -  so I usually end up mixing up a fresh batch for each rifle. 
So.....  if you're using the alcohol solvent technique, don't make a big batch....  unless you crank out rifles like there's no tomorrow.

[Shreckmeister]

So you wait til it's dry or almost dry to hit it with the heat?

[Dr. Tim-Boone]

My experience is that it works better if allowed to dry first...why I am not sure..........  I do Like using alcohol...dries faster  

[Bill of the 45th]

Rob, good choice.  Over the years I played with a lot of choices for both stain, and brown.  The Ferric Nitrate is by far the safest, and most consistent.  One warning, KEEP BOTH THE CRYSTALS, AND SOLUTION CLOSED UP WHEN NOT APPLYING.  They tend to migrate into the air, and any iron in the shop will become browned/rusty in a day or so.  Don't ask!

Bill

[James]

OK, I get to play dumb again. When using the Ferric Nitrate crystals, do you still have to neutralize with a base? If so, how and with what? Thanks, Jim

[Dr. Tim-Boone]

 I haven't been able to get a read on the Ph of the Ferric Nitrate solution but It doesn't seem to bother my hands....don't ask.   I don't neutralize and I have not sen any changes in color over time.   I do rinse the stock with  alcohol on a rag after the blush, just to get off any crytals or any such, then steel wool or burnish with a crumpled brown paper bag prior to and after sealing.

[Jim Kibler]

Even with a properly prepared ferric nitrate solution made from nitric acid, I see no need to neutralize.  I know several others who feel the same as well.   In all the guns I've used it on, I've never experienced any problems with not neutralizing.  Also, I've not seen any objectionable darkening on these stocks over time.

[Joe S]

Has anyone browned with aqua fortis? The steel nose cap is pinned on my stock and after two coats of aqua fortis on the wood the nose cap has a real nice brown to it.

From the archives:
http://americanlongrifles.org/forum/index.php?topic=5142.msg48684#msg48684

If you look at Angier's book on blueing and browning you will see a comment that the nitrate of iron was once used to brown barrels.

My test piece was a wrought iron bolt from the mid-1800's. Real charcoal wrought iron. Gave a nice brown.

But when I tried it on a "modern" ML barrel he would not give a brown that would adhere to the metal.

E. Ogre

When using the Ferric Nitrate crystals, do you still have to neutralize with a base? If so, how and with what?

I have neutralized with baking soda in water.  When this is applied, you see some bubbles form, which is a pretty good indication that there is some residual acid.  It’s interesting that other folks don’t neutralize and see no ill effects.  Next time, maybe I’ll skip the neutralizing step.

[doug]

    I get the impression that some of the posters are mixing apples and oranges.  Plum brown is used for browning barrels and contains several chemicals.  Ferric nitrate made with nitric acid and steel wool is for browning stocks although it will probably rust brown steel as well.  Most of the formulas that Angier published for browning barrels were a variety of mixtures of a small amount of nitric acid, plus ferric chloride and mercuric chloride.  That also describes the solutions that Oscar Gaddy published in the Double Gun Journal for damascus barrels.  I have used the Oscar Gaddy quite a few times on damascus  barrels with mixed results.  Some barrels the pattern just jumps out at you while most are a bit softer and a few do not  demonstrate a pattern at all.   On modern barrels also mixed results with some darkening well and others the rust just cards off.  On minor point and that is that I card the barrel wet because carding with fine steel wool dry is too aggressive

cheers Doug

[kutter]

Cold Acid (rust) Blue solution was a simple combination of Nitric acid and iron dissolved in it. Some formulas added hydrochloric acid in amounts up to/equal with the nitric.
Some added other ingredients of dubious effect to the final finish.

The simple formula was:
Nitric Acid 4oz
Iron (filings, nails, ect) 1/2 lbs
Distilled Water  1 quart

As stated,,hydrochloric acid can be added to the mix in any amount up to the 4oz level equal of the Nitric.

Mix the acids if appropriate,,then add the iron bits.
Do this outside as it creates alot of fumes and smoke.
After the iron is totally dissolved,,then add the water.

Put up into smaller bottles (colored)  and keep away from direct light.

Use as any cold rust blue soln.

I made some and used it many years ago. It worked well but as it became more expensive and difficult to get acid(s),,I started to look elsewhere for a cold rust formula.
I've used many and have settled on LMF for the last 15 years or so.

I do use Ferric Chloride as an etchant between rustings when doing damascus.
It can be used by itself as a browning/rust blue soln. It is the primary ingredient in LMF.

[Rolf]

Just a warning. Nitric acid eats sterling silver. Solutions of ferric nitrate discolors silver by depositing ugly brown iron oxides on it and have to be sanded off.  For rust bluing iron with silver inlays, use only pure ferric chloride solutions.

Best regards
Rolf