Aquafortis

[Benedict]

For years, I have struggled with my bottle of Wahkon Bay Aquafortis.  The stocks came out OK but kept darkening.  This happened even if I washed the stock with a baking soda solution.  People kept telling me that they had no problem.  After some reading and discussion, I decided to try to modify the stain by adding iron.  I took about an ounce of it and cut up a finish nail and put it in the ounce of stain.  That was about 4 hours ago and the nail is virtually gone.  I thought that the stain as purchased had completed its reaction but obviously this is not the case.  Can anyone tell me what might be going on here.

Bruce

[Dphariss]

Part of the problem is that they use hydrochloric in the mix. This produces a different effect than straight nitric acid.
Add more nails, it can only add more iron to the stain. It will work if completely depleted.
Be sure to leave the lid loose on the bottle.

Dan

[HistoricalArmsMaker]

Okay. Now I got questions Dan! Does the hydrochloric deplete after "ingesting" the iron of the nails? Does this actually kill the acid or just weaken it?
(Just like a kid askin questions!) But I myself have always shied away from the acid based stains because they eat off the mountings and continue to darken the wood until black.
Susie

[Benedict]

Susie,
My experience has been just like yours.  The stain gets darker and darker.  My experience with original guns is somewhat limited but I am told that many of them were stained with something called aquafortis (nitric acid).  Eric Kettenberg wrote an article in MuzzleBlasts about how to make it.  He did just used nitric acid but kept adding iron until it quit disolving.  He seemed to indicate that the acid would be depleted at that point but still suggested that it be neutralized after staining.  Based on that, I wanted to try it again.  I was quite surprised to find my stain being SO reactive.  I plan to try it on a sample soon.

Bruce

[Ohioan]

I believe they use the hydrochloric to speed up/ assist in the reaction.  I've read that nitric itself, in its purists form, will not dissolve a nail.  But, when I made my aqua fortis,  I used just plain 30% nitric and it disolved the iron I used.  I then neutralized, twice.

[Stophel]

Nitric acid+water+iron= stain.

A simple, although unpleasant and hazardous operation.


DO THIS OUTSIDE, AWAY FROM EVERYTHING.

Take a glass jar with a mixture of about half nitric acid, half water (the exact ratio seems to matter not), filling the jar about halfway.  Add small bits of iron/mild steel.  Old nails are good.  I don't know about new Chinese nails.  Who knows what junk is in them.  Find some old nails.  DON'T use steel wool!!!  Yes, it will work, but, the reaction is much too fast, the solution will get HOT, and it will belch forth great clouds of red death.  DON'T DO IT.  Now, I will admit, that when I do mine, I will drop in a tiny bit of steel wool, just to give it a jolt, and get the reaction started. 

Put your nails in a few at a time.  Watch them bubble and melt away.  When the nails are gone, drop in a few more.  Yes, it takes time, but what else are you doing?  Could take a couple of days for it to stop dissolving the nails.  Keep going until it quits. (actually, I think it will probably take a LONG time before it really quits, it just slows down quite a bit).  It seems to work better with age too, but will work fine right away.

Oh, and I seem to get different-looking results every time I do it.  Sometimes, I get a clear, almost colorless liquid, with no sediment at all.  Sometimes I get a clear, yellow liquid, with no sediment at all.  Sometimes (and I think this is from my earlier use of steel wool) I get a cloudy orange liquid with LOTS of sediment.  ALL of them work fine.

You can dilute it more, but all you are doing is attempting to stretch the stain out.  I have found that diluting the mixture has ZERO effect on the final color.  Can't make it lighter, can't make it darker.  It does what it does and that's it.  Now, you can dilute it so much that you simply don't have enough acid to work properly on the wood, and it doesn't change color well, if at all.  You slop the stain on the stock heavily.  The water evaporates, leaving the acid/ferric nitrate/whatever.  So, it doesn't really matter too much how much water you had to begin with...

Stain then heat.  I will end up staining the stock several times to take care of any spots I missed either with staining, or bad spots in the surface of the wood I didn't see before and I have to fix them and restain.  The stock should probably be stained twice anyway, just to ensure good color evenly dispersed.

When satisfied, neutralize with a lye solution.  I suppose you could use wood ashes, but I just bought some lye from the grocery store.  Do as I say, not as I do, and wear rubber gloves.  The lye will melt your fingerprints off.  I don't know what kind of solution I use.  I just have a jar of water, and I drop some lye in it....my solution is probably fairly strong.

Then, wash the lye off the stock with water.  I blast it off with the water hose.  Water won't hurt anything.

That's how I do it, anyway. 

[billd]

Would cast iron work in place of steel?

Bill

[smallpatch]

I have really struggled with applying acid to a just finished, nicely carved longrifle.  Just the idea of putting acid on all that hard work, then hosing it down, etc.,etc., just makes me nervous.

On the last one I did for my Grandson, I bought the "Ferric Nitrate" crystals from some chemical warehouse.  Dissolved it in water, and used it just like Aquafortis.  Made beautiful amber/brown color.  I must confess that I did NOT neutralize.  That was several months ago, and it hasn't darkened one bit. 

Not neutralizing may be a mistake, I'm not sure.  But so far so good, and it's just so much easier.
IMHO

[George F.]

Ferric nitrate crystals? please tell us more. A supplier would be good...thanks, Geo.

[Bill of the 45th]

Good discussion, but I notice one half of this equation has been left out so far.  A/F is not a stain as such, but is half of a chemical equation that gives us varying colors due to the amount of different chemicals in the wood, thus we're never sure what we get unless we test that specific wood.  The amount of tannins in the wood give us the amount of darkness up to and approaching black.  The sugars in the wood give it a more reddish color.  As long as there is acid to react with the chemicals in the wood it will continue to darken, and that's why you need to neutralize.  Depending on the type of wood there will be more or less of these chemicals, and even the time of year the tree was cut will affect the outcome from the same mix of A/F.  HCL in the A/F mixture will tend to make a more yellow color.  Ferric Nitrate is basically A/F with the water removed.  A 125 gram bottle, at about $10 is probably a lifetime supply.  Here's where to get it.
The Science Co.
95 Lincoln St.
Denver Co. 80203
Phone-800-372-6726
It also works well as a browning solution.  A word of warning, it will rust anything iron, so keep it stored away from tools, and  anything you don't want browned..

Bill

[Dennis Glazener]

I just do not understand all the concern about using aqua-fortis. I understand people not wanting to fool with making it (acid/water/burs/fumes etc) but as far as using what others have made I don't see any reason to be afraid of it.  I have never had a problem. I have gotten it on my hands without having it burn me (of course I wash it off right away). I have used Baking Soda and household ammonia to neutralize it but several times I didn't neutralize it and after 4+ years I have not seen any indication of darkening.

I apply it with a cotton rag. Most of the time I do put on rubber gloves but not always. My shop is in the basement and is not vented. My wife can smell a can of paint 10 seconds after I open it but I have never had here complain of smelling aqua-fortis.

I have tried other stains and have NEVER used anything that brings out the curl in maple as well as aqua-fortis! Not even close.

I do have one complaint about aqua-fortis, you can do very little to control the color you get using it. Be sure to TEST some on a scrap of the same wood your stock came from. I have had some that turned the curl almost black which I do not care for.

I do want to try the vinegar/iron stain but only to see how it compares to aqua-fortis.
Dennis

[KentSmith]

My understanding was the Wakon Bay used HCl because the same solution could also be used to brown, blue, etc.  I make my own, never got the darkening without neutralizing.  Yes HCl will disolve iron.

[Stophel]

With AF, the color you get, is the color you get.  I have no real control over the lightness or darkness, but that doesn't bother me.  Sugar maple turns more orange, and red maple tends toward more brown.  It all depends upon the particular piece of wood. 

NOTHING works like AF.  NO aniline dye colors the wood the same way...it just loads up the grain with pigments.

Using AF is not really hard.  It does, however, require certain things to be done.  First off, "whiskering".  Now, if you scrape your wood, you will have minimal problems with whiskers.  Set aside your sandpaper.   When I'm ready to stain, I have already scraped the stock finely with a glass slide.  This leaves the surface scraped clean.  When I slop on the first coat of AF (dunk a wad of paper towel into the jar, and slop it on the stock HEAVILY), I will get SOME whiskers, which I will then simply scrape off again with my glass slide.  They generally won't come back up again, no matter how much I stain.  Whiskers are not a problem, even with carved wood.  Plus, you can burnish afterwards, if desired.

The AF does not simply load up the grain with pigments, it changes the color of the wood in a chemical reaction, hence the depth and clarity of AF stained wood.

Neutralizing with lye will change the color of the finished stain.  It turns it a bit more orangy....which is exactly the color you see on so many old guns! 

Supposedly, the vinegar stain does the same sort of reaction as does AF, but I have never been able to get it to work at all...

There is NO reason to fear using Aqua Fortis.

[keweenaw]

The answer to the cast iron question is Yes. I use cast iron chip - pieces removed from a cast iron object milled.  A chunk of cast iron would take a long time to ionize in the nitric acid but it would eventually.  If one checked the pH of a solution of ferric nitrate, the pH would come out well on the acidic side but it makes a weak acid. 

Tom

[Benedict]

The ferric nitrate crystals sound like a good alternative to having a dangerous chemical around.  I will probably try it.

But....when i looked on the internet for ferric nitrate crystals, I found a lot of information (which I did not read in detail) about using ferric nitrate to etch metals.  So if ferric nitrate is used to etch metal, what will it do to the stock and mounts?

Bruce

[Stophel]

It will stain the stock, and do nothing to the metal (presuming you neutralize), otherwise, it can rust your iron, and turn your brass green.  It will take some time to tarnish the brass much, but it will rust iron with abandon.  Another reason to properly neutralize after staining. 

[KentSmith]

I bought some ferric nitrate crystals once to see how they worked.  I bought enough for 3 lifetimes.  They work fine, not as well as home brewed ferric nitrate or ferrous nitrate or whatever you actually get depending on all the variables.  I mixed a teaspoon with four ounces of distilled water and disolved the crystals.  Have trouble diluting the stain  like I can the home brew so I haven't been able to vary the darkness much to my satisfaction - but that may be me or the wood as Stophel said.  Email me if you want a couple ounces and I'll send them if you pay the shipping.