Removing furniture when using aquafortis?

[SPletcher]

If the solution is made correct there should be no "acid" left to react with the brass furniture, right?

Was thinking about leaving on butt plate, have to leave on muzzle cap as I have already installed using copper rivets.

Thoughts?

Thanks,

Steve

[rich pierce]

Not a good idea IMHO.  I always "need to neutralize" and note that once I neutralize, the stock does not want to take more stain.  So I guess I am not making AQF that is "dead" and I'd expect nasty colors from the brass.  I usually only leave the nosecap on and avoid overruns there.

[Bioprof]

I don't think that dissolving metal in acid will neutralize the acid.   The only thing that will neutralize acids are bases.   Because most people neutralize their stock after AF treatment, the short time  that it would be in contact shouldn't cause much of a problem; maybe a little discoloration that could be removed with fine steel wool.

[T*O*F]

I don't think that dissolving metal in acid will neutralize the acid.   The only thing that will neutralize acids are bases.

C'mon.....a bioprof shoulda known this.

You are not "dissolving" metal in acid, you are "reacting" the metal with the acid to form salts and water.  You don't end up with what you started with.  If the reaction is complete, there is no acid left.  If the reaction is partial, there will be.

The problem with guys who make their own is not carrying the reaction all the way to completion; ie, they don't add an excess of iron.

[Bioprof]

OK, I stand corrected.    I looked up the reaction and found the following:

2 Fe +8 HN03 = 2 Fe(N03)3 + 2 NO +4 H20


Still, most users of AF find that if they don't neutralize after applying the AF, their stock will turn black over time.   This would seem to indicate that there is still acid left in the solution.   

I have also heard that if you don't neutralize, the brass hardware will turn green over time as a result of the acid reacting with the metal.

I may do some testing with a pH meter the next time I make up a batch of AF and see if I can get the solution to completely neutralize if I continue to add iron.

[oakridge]

Just a comment, for what it's worth. Not being a gunbuilder, I haven't had much experience with AF. Awhile back I had to refinish a stock that someone had sanded down badly. It had beautiful curl to the maple. I put on some AF out of the little bottle I got from Track, did the heat gun thing, and set it aside. Came back some time later and applied the finish. Oops! Forgot to neutralize the AF. It's been a while now and no change to the color. Was I just lucky? The stock had several German silver inlays that weren't affected by the AF. Don't know what it does to brass.

[Dennis Glazener]

I have only neutralized AF one time and have not noticed a difference. Of course the oldest one I have left is only about 6 years old.
Dennis

[Dphariss]

Just a comment, for what it's worth. Not being a gunbuilder, I haven't had much experience with AF. Awhile back I had to refinish a stock that someone had sanded down badly. It had beautiful curl to the maple. I put on some AF out of the little bottle I got from Track, did the heat gun thing, and set it aside. Came back some time later and applied the finish. Oops! Forgot to neutralize the AF. It's been a while now and no change to the color. Was I just lucky? The stock had several German silver inlays that weren't affected by the AF. Don't know what it does to brass.

How complete the reaction is has an effect as well. If you fail to heat the wood deep enough you may leave unreacted acid in the wood which can cause a color change. This can occur using propane torches for heat.
I am told that tannic acid will continue to darken a stock and from experience AF stain adulterated with HC acid will get browner with time. I found this out the hard way but it takes 6-10 years.
I don't use copper alloys for inlays. If I have brass I cannot remove such as a forend cap I try not to get too much stain on it.
The more iron you put in the acid the better the color will be, the acidity of the stain is not important other than too much can damage to color. Weak acids like vinegar carry little iron and thus the staining is not the same as AF in color or function or so I have been told by researchers.

Dan

[Ohioan]

I got lost when the chemical reaction formula popped up.  I just barely passed my high school chemistry class, of course, if I had had a teacher.. but I digress.

I left my nose cap on when I stained my rifle with my home made AF.  It was riveted on, so there was nothing I could do about it. 

I stained it this past spring, and there has been no noticeable effect to the color of the brass. 


I added Fe to the Nitric Acid until it wouldn't take anymore.  I used a high quality Wagner heat gun to heat the stock, I couldn't hold the stock it was so hot, but didn't burn/char.  I did neutralize the stock.

[Stophel]

I take my brass off because it is a major heat sink, and makes it hard to turn the color around places like the trigger guard tang.