Aquafortis ferric nitrate iron nitrate, oh my.

Hotwheels81

Hotwheels81

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I have a rather nice… some would say “fancy” while others would even go as far as to say “extra fancy” piece of curly maple coming my way that I’d sure like to maybe look reallllly pretty, unfortunately it it seems that buying a nice name brand iron nitrate finish is kinda hard in Canada? I’ve found it in crystal form from sculpting supply stores and lab grade reagent on Amazon tho…

Do the crystals rehydrate into the rite stuff?
Am I missing some way to get my paws on a cup or two of this in the great white north?
Why is it so bloody expensive? 🤣
 
I'll have to look in my books for the recipe, but I believe it was as simple as dissolving degreased steel wool in a nitric acid/water solution.
 
flintyboom said:
I'll have to look in my books for the recipe, but I believe it was as simple as dissolving degreased steel wool in a nitric acid/water solution.
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That is correct (but just NA, no water). Just dissolve as much iron in it as it will take, until it won't dissolve any more and you are good. If you know someone that works at a water treatment put they may be able to spot you some nitric acid.
 
Licensed to kill said:
That is correct (but just NA, no water). Just dissolve as much iron in it as it will take, until it won't dissolve any more and you are good. If you know someone that works at a water treatment put they may be able to spot you some nitric acid.
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I do not believe that is correct.
I believe an approximately 70% nitric acid solution is used, which is a nitric acid/water solution. That said, good luck finding the nitric acid. I have been looking for some time without success.
The ferric nitrate crystals dissolved in water make the same product, are used in the same way and have the same effect. That said, there can be slight tonal differences between the various commercial AF solutions and between those and the ferric nitrate solution. The tonal differences are due to different types of iron being used in making the product. The effect also varies between pieces of wood, so it is best to do a test on an offcut from the stock. Also, the effect can be enhanced (darkened) by applying a tannic acid solution and letting it dry prior applying the ferric nitrate or AF. In addition, applying and blushing a second ferric nitrate/AF solution can slightly increase the effect.
As an aside, the commercial aqua fortis solutions are not really aqua fortis. They are ferric nitrate solutions. Aqua fortis is the Latin name for nitric acid. Ferric nitrate is created by dissolving iron (the ferric part) in nitric acid (the nitrate part). The commercial products can still be slightly acidic and it is best to neutralize with a base, such as washing soda to stop further darkening and potential rusting of metal parts. I have never had to neutralize my home-made ferric nitrate solution.
If someone knows where small amounts of approximately 70% nitric acid can be purchased via mail order, please post the info.
 
B_noser said:
I do not believe that is correct.
I believe an approximately 70% nitric acid solution is used, which is a nitric acid/water solution. That said, good luck finding the nitric acid. I have been looking for some time without success.
The ferric nitrate crystals dissolved in water make the same product, are used in the same way and have the same effect. That said, there can be slight tonal differences between the various commercial AF solutions and between those and the ferric nitrate solution. The tonal differences are due to different types of iron being used in making the product. The effect also varies between pieces of wood, so it is best to do a test on an offcut from the stock. Also, the effect can be enhanced (darkened) by applying a tannic acid solution and letting it dry prior applying the ferric nitrate or AF. In addition, applying and blushing a second ferric nitrate/AF solution can slightly increase the effect.
As an aside, the commercial aqua fortis solutions are not really aqua fortis. They are ferric nitrate solutions. Aqua fortis is the Latin name for nitric acid. Ferric nitrate is created by dissolving iron (the ferric part) in nitric acid (the nitrate part). The commercial products can still be slightly acidic and it is best to neutralize with a base, such as washing soda to stop further darkening and potential rusting of metal parts. I have never had to neutralize my home-made ferric nitrate solution.
If someone knows where small amounts of approximately 70% nitric acid can be purchased via mail order, please post the info.
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When I made mine, >20 years ago I did not dilute the NA. However, I see no reason why you can't if you like. If you do choose to dilute, always remember, "do as you oughta, add acid to watta". Never add water to acid.
 
It is much easier to lay hands on the crystals than to get nitric acid, it would actually be easier for me to have some of the actual iron nitrate from Kiblers mailed state side to the in-laws in AZ and driven back with em in the spring instead of trying to get my hands on nitric acid but most anything that contains the word nitric is not something I’d want to try crossing the boarder with…. I can make nitric acid but by the time I buy the lab equipment I may as well just buy the crystals!… so if the crystals will work I’m thinkin I’ll just go that route.

To make ferric/iron nitrate from scratch all my research says to just drop iron (not steel) into nitric acid till it stops reacting, can’t imagine the process would completely neutralize the acid tho…. Don’t much care to find out, I’d probably end up going down another rabbit hole and losing my mind.

I don’t have much in the way of colour preferences I’m more just after the traditional look of the original or “period” finish, it’ll be beautiful no matter what I’m sure…
 
Hotwheels81 said:
It is much easier to lay hands on the crystals than to get nitric acid, it would actually be easier for me to have some of the actual iron nitrate from Kiblers mailed state side to the in-laws in AZ and driven back with em in the spring instead of trying to get my hands on nitric acid but most anything that contains the word nitric is not something I’d want to try crossing the boarder with…. I can make nitric acid but by the time I buy the lab equipment I may as well just buy the crystals!… so if the crystals will work I’m thinkin I’ll just go that route.

To make ferric/iron nitrate from scratch all my research says to just drop iron (not steel) into nitric acid till it stops reacting, can’t imagine the process would completely neutralize the acid tho…. Don’t much care to find out, I’d probably end up going down another rabbit hole and losing my mind.

I don’t have much in the way of colour preferences I’m more just after the traditional look of the original or “period” finish, it’ll be beautiful no matter what I’m sure…
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I use the crystals, faster easier and exactly what you get from making your own from acids without the fun of working with acid AND you don't have to neutralize your stock after.

That being said, the random(ish) colour you wind up with is dependent on the tannins in the wood itself - I prefer to use leather dyes over AF
 
sean69 said:
I use the crystals, faster easier and exactly what you get from making your own from acids without the fun of working with acid AND you don't have to neutralize your stock after.

That being said, the random(ish) colour you wind up with is dependent on the tannins in the wood itself - I prefer to use leather dyes over AF
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I too made a switch, really been liking leather dyes as well, easy to mix to basically any shade or colour you want, doesn’t hide the grain allowing any figure or chatoyancy to still come through.
 
Licensed to kill said:
When I made mine, >20 years ago I did not dilute the NA. However, I see no reason why you can't if you like. If you do choose to dilute, always remember, "do as you oughta, add acid to watta". Never add water to acid.
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I'm largely going off memory here, but IIRC for an acid to do its thing it needs to be in solution with a solvent and that solvent is typically water. So you might not have diluted whatever you bought, but it was likely already an acid/water solution.

A quick google suggests most store-bought nitric acid is 68% HNO3. And apparently walmart sells 18M Sulfuric Acid stateside!? lol https://www.walmart.com/c/kp/nitric-acid
 
Suther said:
I'm largely going off memory here, but IIRC for an acid to do its thing it needs to be in solution with a solvent and that solvent is typically water. So you might not have diluted whatever you bought, but it was likely already an acid/water solution.

A quick google suggests most store-bought nitric acid is 68% HNO3. And apparently walmart sells 18M Sulfuric Acid stateside!? lol https://www.walmart.com/c/kp/nitric-acid
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That is a fair statement. I got my NA from a water treatment plant and can not say for sure what the concentration was, just that I did not add any water.
 
The nitric acid used by water treatment plants is likely in the vicinity of 70%. Concentrated nitric acid tends to be very dangerous stuff and not something an amateur should be messing with.

Ferric nitrate crystals are available in Canada. Do an internet search. A friend recently bought some from these folks.
https://sculpturesupply.com/products/ferric-nitrate

I recommend against using leather dye. In my opinion, it obscures the grain and muddies the appearance. I would expect the effect on curly maple to be anything but positive. Aniline dyes would be a better choice if color adjustment is required, but the ferric nitrate, possibly combined with tannic acid, will likely do the job.
 
I have made ferric nitrate stain in the past and would make some observations; Most important is if you are working with nitric acid, ALWAYS pour the acid into water, never the reverse or you will get a violent vapour explosion and you decidedly do not want that. Also in terms of the ratio of acid to water, you need to know the concentration of the acid; I diluted it to about 30% acid starting from concentrated (95% ). I used steel wool as my source of iron and did not bother degreasing it. The reaction gives off very corrosive orange vapours and a lot of heat; do it outside or you will rust everything nearby. Also when the first portion of steel wool is dissolved, let the solution cool a bit so that the acid solution does not boil over. Finally wipe the solution on the clean and sanded wood which will give the wood a sort of washed out coca cola colour then go over the wood with a heat gun until the colour changes to dark reddish brown. The reds will fade over a week or so. If you wife is not home, you can also heat the wood over the large element on the kitchen stove :>). Finish with a very light sanding with very fine sand paper

cheers mooncoon
 
B_noser said:
I recommend against using leather dye. In my opinion, it obscures the grain and muddies the appearance. I would expect the effect on curly maple to be anything but positive. Aniline dyes would be a better choice if color adjustment is required, but the ferric nitrate, possibly combined with tannic acid, will likely do the job.
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Depends on the dye and concentration - I've always had great results. As for Aniline - I gave up on them, they are not UV safe (at all) and I found unless you sealed them with a polymer they will bleed through oil finishes and stain your hands/cheek ... :(
Though there are lots of types and brands of aniline dyes - the stuff you get from Lee Valley is definitely not suited for stocks.


Hotwheels81 said:
Does the colour fade over time using leather dye?
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I use the Eco-flow dyes, the cheaper ones are more UV safe than the "pro" version. So that is a case of "read the label" for UV resistance.
I've had no problem with them fading or bleeding through any finish.
 
Hotwheels81 said:
Does the colour fade over time using leather dye?
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The one time I used leather dye it did fade but that could have been the dye that I used. I know I used Fiebings but don't recall which one (it was 20 years ago). There likly are leather dyes out there that will not but, just be aware that some will fade. If you choose to go the leather dye route, I don't recommend using just "leather dye", try to find one with a proven track record of not fading over time
 
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