Aqua Fortis, making it

A

andrew_cc

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Jan 27, 2010
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Hello all,

Ive have searched the internet and the search tool before asking but I am still at a loss.

I want to use aqua fortis on a knife handle, Its hard to come by in the UK, and as I have ready access to chemicals I thought Id just make it myself.

What I haven't been able to find is a recipe for it... as I understand, it is dilute Nitric Acid and 'iron'

My questions are how dilute, (Ill be starting with neat acid)? And also, what iron should I put in there, iron chloride, iron oxide etc?

After the aqua fortis I am planning to soak the wood in linseed oil, then maybe a beeswax finish...


Thanks all.


Andrew
 
OK I borrowed this from another forum site. It is used as a stain on traditional muzzle loaders qutie often. Here is one mans formula:


I start with concentrated nitric acid diluted 50:50 with water in a ventilated hood at work (the fumes given off are deadly -- work in a well ventilated area and stay away from the fumes). Dissolve iron until it won't dissolve any more. Dilute with water as needed before using. Be carefult with the acid. It will cause severe burns.

I neutralize with 1 M NaOH after applying the AF to the wood and heating. If you don't, it will keep turning darker until the wood is black.

I sometimes have to dilute the AF with as much as 1:12 with water to keep it from getting too dark. Be sure to test it on a scrap of wood from the same stock. The color that you get depends on the wood and may vary. You can always tint with alcohol stains if you don't like the color.

Here is another excerpt:
Aqua fortis maens strong water in latin. You don't neccessarily need to put iron in the nitric acid. The iron will give you a reder color. The more iron you put in it the reder the color will be. With no iron you will get a dark brown but each piece of wood will be different. I never use stronger than 10% nitric acid. With the stronger stuff it's too hard to control the shade.


Note* some say it turns wood green with age if not neutralized after application.
Be careful with the stuff Aqua Fortis and the the resulting fumes can be dangerous. Hope this helps!
 
thanks for digging those references up, I found a few more over lunch and have been thinking....

Im wondering whether the acid is important to this mixture at all??

Iron will react with Nitric Acid to form the iron nitrate... the purpose of driving this reaction to completion by adding more and more iron until none will react further is to 'use up' the acid.... so essentially now all we have is a water solution of iron nitrate, with maybe a bit of acid floating around, but still mainly water


wouldn't it be easier to just use iron nitrate dissolved in water then?


Im very ignorant of wood treatment methods, Im just looking at this from a chemistry point of view so forgive any glaring misunderstandings...
 
Dixieblade57 said:
I start with concentrated nitric acid diluted 50:50 with water in a ventilated hood at work (the fumes given off are deadly -- work in a well ventilated area and stay away from the fumes). Dissolve iron until it won't dissolve any more. Dilute with water as needed before using. Be carefult with the acid. It will cause severe burns.

I neutralize with 1 M NaOH after applying the AF to the wood and heating. If you don't, it will keep turning darker until the wood is black.

I sometimes have to dilute the AF with as much as 1:12 with water to keep it from getting too dark. Be sure to test it on a scrap of wood from the same stock. The color that you get depends on the wood and may vary. You can always tint with alcohol stains if you don't like the color.
Click to expand...

First those were two different opinions I borrowed from another site.
I am not a chemist but I think you end up diluting the nitric acid with the water and the iron but the process really needs the nitric acid to make it set deeply into the wood.

One thing I didn't mention in my previous post is you have to neutralize the process in the end to stop the reaction. I think someone said something about washing in baking soda. The fellow in the info I had borrowed has his own formula for neutralizing! My understanding is that if you do not neutralize the process it will continue over time and that is what tends to turn it green with age!

Therefore I am assuming the nitric acid is what has to be neutralized! So yes I think I think you are only basically adding enough iron to achieve the red color instead of brown, not completely cancling out the nitric acid!
 
wouldn't it be easier to just use iron nitrate dissolved in water then?
Click to expand...

It works just fine...you can get it from The Science Company in crystal form

FWIW - I've been using AF for over forty years and switched to the crystals a few years back due to some health concerns (when making it yourself the fumes are HIGHLY toxic) and have found NO difference in the two other than the normal differences between the pieces of wood. Remember this works via a chemical reaction between the iron in solution and the tannins in the wood so the wood itself is a big factor. For more info on AF and how it's used, etc. I would recommend going to http://americanlongrifles.org/forum/index.php
Some of the best of the best muzzlelaoding rifle makers hang out there and have hundreds of years of combined experience with it. IMO AF produces a color and chatoyance on maple in particular that NO other product will produce and has to be seen in person to appreciate....

And yes whether you use AF or FN crystals one needs to blush it with heat and then finally neutralize it with a good base i.e. lye, potash (traitional), washing soda, or ammonia all work.
here are two test samples - note the face on the left piece that turned much darker after being exposed to sunlight since I didn't neutralize it...
maple-001.jpg

these also have a light coat or two of a period real linseed oil based varnish to enhance the grain.....for more examples see the hawks on my website...

My understanding is that if you do not neutralize the process it will continue over time and that is what tends to turn it green with age!
Click to expand...
This is actually a misconception due to some folks selling chromium trioxide as AF and it is that which will turn green over time. When first applying real AF it will sometimes have a greenish tinge but once you blush with heat it will turn to the brown/red brwon color so desired.
 
Most helpful information indeed, thank you all for helping out.

Wild Rose, its good to know I can just use the Iron nitrate crystals, we have a fume hood at work, but then there is always answering the inevitable questions of why am I putting old nails in acid..... though I think most people expect a certain amount of old behavior from me :p
 
Why not ebonise instead, dissolve steel wool in vinegar, works well on leather and wood with a high tanen content not dangerous at all.

Richard
 
Tinbasher said:
Why not ebonise instead, dissolve steel wool in vinegar, works well on leather and wood with a high tanen content not dangerous at all.

Richard
Click to expand...


As this is my first attempt at this for real, I might try a few different methods on the same wood Ill be using to gauge the different effects. I shall add that one to the list as Ive heard other members say some good things about it.

When Im done with the tests, I might post some pictures up of the different effects side by side, hopefully some people might find that useful.
 
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