Aqua Fortis 101

[BillinOregon]

Well, I have had a bottle of Wahkon Bay aqua fortis and a bottle of WB Tru Coat in the shop for several years now, awaiting a project. I have a maple stocked fusil kit ready for finishing. The label on the aqua fortis says to apply liberally to a section of stock, then heat to get the deep brown. Instructions then say to proceed to apply Tru Coat. Nothing about neutralizing.
After searching here for AF posts, I find a number of suggestions, and an intriguing comment that Hershel House slops it on good and thick over the whole stock at once.
Can I do this? Seems like there would be less risk of having uneven sections that don't match up.
Next question is neutralizing with backing soda and water. What proportions? Do you just pour a quart or two over the whole stock, let dry and call it neutralized?
I am of course looking for a nice, dark, EVEN finish that won't turn green on me.
Thanks for any advice or insights.

 

[tallbear]

Bill
Yes you should apply it all over the stock at once.Then let it dry completely before blushing it.You may have to do it twice as I always find that I miss a spot after blushing it.I always neutralize Wahkon-bays stuff as it's very acidic.I use common household ammonia.Never like the baking soda as it took too much rinseing to get rid of it which cause the grain to raise to much to my likeing.Do some test runs on some scrap!!

Mitch

 

[Tumblernotch]

I've used Wahkon Bay AF on all my maple stocks. It soaks in and dries kinda quick, so I only cover fairly small areas at a time before heating. I used to use an acetylene torch to activate with but now use one of those little butane torches like you buy at Harbor Freight. I've not had any problem with unmatched sections. One way to avoid that is to go lighter on the stain where you know the joints will be, sort of feather it and you can overlap the next section over it. Actually, I've heated a section before and added more acid to try to make it darker and it didn't reall get any darker.

As for neutralizing, just slather on some boiled linseed oil and let it sit for a few minutes and rub it down. That'll kill it. As a matter of fact, that's all I used to finish some of my stocks. Using AF shouldn't turn your stock green, that's caused by chromium in another stain (can't remember the name, but we did a thread about it awhile back). Now, if you don't heat the AF enough, it will get a greenish cast to it, but that will be avoided if you apply enough heat. After you finish, you may find some little green areas here and there. If you do, just go over it with your torch. You may have to dab a little fresh acid on it if you wait too long.

I also use Wahkon Bay Browning Reagent for my iron work and barrels. It works fast and does an even job (as long as you do your part). I also use boiled linseed oil to kill it.

 

[tallbear]

Since Linseed oil tends to be acidic I'm curious how you can neutralize an acid with another acid????Please explain.

Mitch

 

[Tumblernotch]

I was told years ago that it kills the acid better than anything else by some old time builders, so I used it. And it works! Track of the Wolf put out a "how to" article on using AF and they recommend using linseed oil or a linseed oil based finish. I'm no chemist, so I can't explain how this stuff reacts, all I know is that the two materials have been used together to create the most beautiful maple finishes for many years and the best browning of iron and that they work for me, which reminds me that I need to order some more WB AF.

 

[dlpowell]

Who sells Wahkon Bay AF?

 

[tallbear]

I don't dissagree that Linseed oil can be used as a finish after aqua-fortis and a very nice finish I use it myself from time to time.I do disagree that you are neutralizeing the leftover acidity in the aqua-fortis with the linseed oil.It is certainly possible to put the finish over un-neutralized aquafortis and many builders do it that way.When I make my own aqua-fortis I make sure that it is not very acidic and sometime skip neutralizeing depending on the rifle I'm building.As wahkon-bays aqua-fortis is actually aqua-regia(nitricacid,hydrocloric acid water and iron) and tends to be very acidic which can darken the wood or discolor the edges of inlays over time. Some builders includeing myself like to neutralize it before finishing.To do this you need a base to neutralize the acid hence the ammonia,baking soda or wood ashes in water.

Mitch

 

[BillinOregon]

Don: I got it from the owner over off of Carl's Traditional board several years back. Can't recall his name, but a very fine gentleman.

 

[Soractus]

Is heating the stock really necessary? Or is it just a way of speeding up the process?

 

[tallbear]

Heating the stock is absolutly neesasary!!With out it the stock is a sickly gray/green color.

Mitch

 

[Soractus]

With straight nitric acid? Interesting reaction.

I don't have a piece of maple handy to experiment on, but I'll take your word for it.

 

[Tumblernotch]

All I know is, I use boiled linseed oil to kill the acid on both wood and iron. After I rub it well and wipe off the excess, the wood has a rich red-brown color and the iron doesn't rust any more. I use no other agent to kill it. If it doesn't work, don't tell my rifles about it. They think they were finished years ago. :wink:

 

[rabjr]

With straight nitric acid? Interesting reaction.

I don't have a piece of maple handy to experiment on, but I'll take your word for it.

Yes you heat the stock, Nitric of Iron acid is what? It's dissolved Iron particles that is soaked up into the wood, it does not stain the wood, it actually changes the wood color. There are better people than me to explain it but when you heat the wood to "blush" it, your causing the Iron particles to flash rust, thats where you get your color. Heres a gun I built for a friend, it is Red Maple and the Nitric Iron acid came from Eric Kettenburg. It went from an ugly puke green to this after using a heat gun and a few coats of finish.
http://www.nimrodsplace.com/lewisandclark28.html

 

[paulvallandigham]

I don't think linseed oil Kills or " neutralizes" the acid as much as it seals the acid away from AIR that it needs to react. There will be a minor amount of air in the wood cells, of course, but that is usually used up blackening the stock. The linseed oil seals the wood, keeping air away from the wood.

 

[Bean]

So to clarify the process...?

Apply the AF to the wood, heat with a heat gun, wipe down with amonia and then apply linseed oil.

I would assume you would repeat the AF a couple of times prior to the heat?

 

[rabjr]

So to clarify the process...?

Apply the AF to the wood, heat with a heat gun, wipe down with amonia and then apply linseed oil.

I would assume you would repeat the AF a couple of times prior to the heat?

Make sure that AF drys before heating it and be careful when you "Blush" it. You can burn the wood very easy. You can stop there or do another coat of AF and heat it again, can do it as a few times if you want to.

Some neutralize it, some don't. I always have.

If you want to use linseed oil, by all means do do but I would use something else, like Chambers finish, True oil.

 

[tallbear]

Aqua-fortis is not staight nitric acid.It is a mixture of nitric acid and water with iron dissolved into it.If you use straight nitric it will do nothing but burn the wood.The color with aqua fortis is the iron in the solution changeing to an oxide when the heating is done.Because the iron is dissolved and is almost molecular in size it is a much finer pigment that can be ground mechanically as in something like a minwax stain.This is one reason to use aqua-fortis as it doesn't muddy the grain.

The basic process that I use is apply the aqua-fortis over the whole rifle and let dry.Heat the stock until the wood turns color.Be careful not to burn the high spots.Do a second coat if you want the same way(I useually do).After two coats neutralize and apply finish of your choice.

This rifle is stained useing this process I've descibed.

Mitch

 

[BillinOregon]

Swampy, Tallbear: Gorgeous guns!
Tallbear: To neutralize, you just pour household ammonia over the blushed stock and let dry?

 

[paulvallandigham]

The question on this post seems to be about whether, and if so, HOW you neutralize the AF. So, Can you explain in more detail how you are neutralizing the Aqua Fortis. Great looking stock, BTW. I wish every AF stock came out that nice. Most are very much more dark in color.

 

[bioprof]

Anything that is basic can be used to neutralize aquafortis that is too acidic. I use about a 10% solution of NaOH (lye).

I strongly suspect that the trick to getting good results with aquafortis is to use the right kind of wood. The best results, in my opinion, is with very hard sugar maple, the harder the better. It's been my experience that if you have softer spots in the wood, it will turn out almost black. Surface preparation is also important. I've noticed that in areas where it's hard to sand, the pores remain more open and it turns out darker in those places. If you have soft wood, burnishing it beforehand might help keep it from turning too dark. These are just my perceptions though and I may be way off track. :idunno: