making aqua fortis

[yip]

  I'm planning on making some aqua fortis stain, using steel wool for the metal, I was told that steel wool has oil on , what's the best way to clean the wool?

[tallbear]

Yip
I would avoid using steel wool ,use small chunks of iron instead much safer with better results.Steel wool causes a real violent reaction and can result in a muddy looking stain.

Mitch

[Mark Elliott]

I cut off thin slices of wrought iron from a 1 1/4" bar.   It seems to help if you leave it out in the weather to rust a bit first.   Steel wool never gave as good a result. 

[grabenkater]

Can someone explain how to make aquafortis?

[smart dog]

Hi Yip,
Why not save yourself the trouble and just buy ferric nitrate powder from the Science Company.  Mix with water and you basically have aqua fortis.  Moreover, you can adjust the concentration to achieve different results and you don't have to fool with nitric acid.

dave

[Mark Elliott]

Hi Yip,
Why not save yourself the trouble and just buy ferric nitrate powder from the Science Company.  Mix with water and you basically have aqua fortis.  Moreover, you can adjust the concentration to achieve different results and you don't have to fool with nitric acid.

dave

What fun is that?   

[smallpatch]

Yeah, for $10, and a mix with water=ferric nitrate.

Much more money, rubber gloves and apron, safety glasses, fuming acid, dangerous spills, =unpredictable results, and ferric nitrate, and some residual acid of unknown strength.
Sounds like fun to me!!

[Ed Wenger]

Ha!  That's funny Mark!

Grabenkater, you make Aqua fortis by mxing nitric acid with water.  Recently there was a mention by Eric Kettenburg about using alcohol instead of water so as not to raise the grain as much.  Anyway, the nitric acid comes in various strengths.  I believe I'm using 70 or 75%...  That is typically mixed in a ratio of 1 part acid to 5,6, or 7 parts water.  ADD THE ACID TO THE WATER, not the other way around.  Then add a chunk(s) of iron.  The acid will dissolve the iron, or at least a good part of it, depending on size.  I typically let it "cook" until I get a tea color, usually about a day or day and a half.  The longer it absorbs iron, the less acidic the AF will be, although I would still neutralize it with ammonia after it's applied to the stock.


         Ed

[rich pierce]

I add the iron bit by bit.  It's fun to think that wrought iron is best but it can have as many impurities as mild steel so I don't worry about that.  If it gets muddy when I make it I add more acid and water in same proportions.

[tallbear]

I make my own Nitrate of Iron(aqua fortis) stain.I use a mixture of 4 parts water(distilled/rain) to 1 part nitric acid.I slowly add small chunks of wrought iron/mild steel(DON"T BREATH THE RED SMOKE!!!!!!).I make sure not to let the reaction get to violent as I believe the temperature reached affects the final stain color.I vary the type of iron used in different batches as that also affects the final stain color.Wrought iron tends to give me more reds,mild steel gives me more browns.I do this until the reaction completely stops.Once there is no more reaction I put it in a mason jar for at least a month with the lid loose or it will bust.After a month or so I strain through cheese cloth and it's ready to use.

Mitch Yates



Notice two batches made at the same time using different metal sources yield different color stains. They will stain the wood differently also once blushed.



While certainly the wood played a part the top stock was stained with Nitrate of Iron stain made with mild steel(more browns) and the bottom stock was stained with Nitrate of Iron stain made with wrought iron(more reds)

[T*O*F]

Go to your local place that turns brake drums and rotors and get a coffee can full of the turnings.  They will give you a fairly quick reaction because of the high surface area of the shavings.  If you get sludge when you are done, just decant your mixture into a different container for storage.

The process is also an exothermic reaction which gives off heat.  This can result in having a super-saturated solution, which when cooled and stored will allow some of the ferric nitrate to precipitate out of the solution.  In the past, I have just shaken the bottle to get it into suspension and use it as is with no ill effects.

[sqrldog]

The original aquafortis we used from our Minnesota supplier in the earlier years was the A O Zistchang formula containing both nitric and hydrochloric acid. Without getting into any formulas(since they are available from printed material elsewhere) the concentrate was exposed to iron in the form of nails and after reaction diluted to make aquafortis or browning solution/ blueing solution. The browning and blueing solution being more dilute than the aquafortis. Great care should be used with either of these acids during reaction to  avoid breathing the fumes and use heat resistant glass or other nonreactive container. It is bad stuff. Final product should be stored in an amber colored bottle in a dark  place if possible. It is cheaper and easier to buy these products already prepared. Tim

[yip]

  i'm not throwing any stones here, but watching Hershel House make his solution he uses steel wool. you guys have great ideas, maybe i'll try steel shavings............yip

[okieboy]

 Regarding making the stain by mixing ferric nitrate powder with alcohol, the references always seem to mention using denatured alcohol. Since expense is not a concern (if you chose this hobby), would high proof (150 to 190 proof) grain alcohol be a better choice because it is a higher concentration of the alcohol. This is what I use for dissolving shellac flakes, and it is far superior to denatured alcohol for this.
 Just curious.

[jerrywh]

 As I said once before , You better read up before mixing ferric nitrate or nitric acid with alcohol.  Don't take my word for it just check it out. You could get in trouble mixing the two in some cases. High proof and nitric together make for a violent reaction.

[Eric Kettenburg]

I probably should have kept my mouth shut about the alcohol.  I do a lot of experimental stuff and you can find many references to some seriously dangerous s**t in old 19th century texts, but I've not thought about things in that manner.  For me it's always about the end result, or it used to be.  I do find myself thinking more about safety.  I have not looked into the dangers of mixing nitric acid with alcohol but it seems as though it's a situation primed for a real problem if not executed correctly and apparently I executed it correctly when I was fiddling around with it, but I would hate to see someone read about this and then create a real situation or injure themselves or others.

So be careful.  Probably best to stick with water.

I don't like steel wool, leaves a lot of dirty greasy residue that needs to be strained/filtered out, and I have first-hand seen it cause issues with greening that I do not otherwise get with real iron or mild steel scraps.  Also, as mentioned above, it can very quickly get crazy hot and then turn into a nuclear situation.

I do not think there is any reason whatsoever to get hydrochloric acid involved, also can lead to greening in my experience.

[Sawatis]

The original aquafortis we used from our Minnesota supplier in the earlier years was the A O Zistchang formula containing both nitric and hydrochloric acid. Without getting into any formulas(since they are available from printed material elsewhere) the concentrate was exposed to iron in the form of nails and after reaction diluted to make aquafortis or browning solution/ blueing solution. The browning and blueing solution being more dilute than the aquafortis. Great care should be used with either of these acids during reaction to  avoid breathing the fumes and use heat resistant glass or other nonreactive container. It is bad stuff. Final product should be stored in an amber colored bottle in a dark  place if possible. It is cheaper and easier to buy these products already prepared. Tim

Yeah this is the old Niedner gun blue...it is a great gun blue...if you have the patience for the application process...never thought of trying it as a AF substitute...you don't let the acid reaction go to completion with the Zistchang formula so its still quite caustic and aggressive on the metal unlike the AF which you want the acid to be spent (as best as you can) ... I guess you could neutralize it ...don't know how it would behave. Interesting thought though!
John

[sqrldog]

I've used it on numerous stocks and never had a green tint problem. It blushes maple better than any other reagent I've used. Never nuetralized it but then I like a darker colored rifle. Each to his own. Tim

[davec2]

I believe I am beating a dead horse here, but I will re-post something I have posted before on this subject........

Part of the problem and confusion with all these concoctions is the incorrect nomenclature often being used here.  Aqua Fortis is the medieval, alchemical name for nitric acid...just the acid...not iron or anything else dissolved in the acid.  The acid, when applied to wood and heated, even with no iron present, will indeed color the wood darker.  The Ferric Nitrate solution (very improperly called "aqua fortis") generated when iron is dissolved in nitric acid, will produce a darker color when it is applied to wood and heated as the iron is now part of the chemical process that imparts color to the wood.  So if you ask a chemical supply house for "aqua fortis" they will give you nitric acid, not the ferric nitrate solution most are looking for.  So, as Dan Phariss correctly points out, you make ferric nitrate stain using aqua fortis (i.e. nitric acid).  Or, you can make ferric nitrate stain with ferric nitrate crystals...either way, it's the same stuff and neither of them are "Aqua Fortis".  The stain is not "Aqua Fortis" (which, by the way, means "strong water" in Latin.  They called it that because it dissolves a lot of stuff !)  

From time to time, I also see the term "Aqua Regia" bandied about.  Aqua Regia" ("Royal Water" in Latin) is a mixture of nitric acid (HNO3) and hydrochloric acid (HCl) ("Acidum Salis" in Latin because it was made with salt and sulfuric acid).  It is called Royal Water because it will dissolve gold.  Something neither nitric nor hydrochloric acid can do alone.  I recently had someone tell me how dangerous hydrochloric acid was.  They were surprised to learn that they had a stomach full of it and that a lot of people, who own pools or spas, throw a big slug of "muriatic acid" (i.e. hydrochloric acid) in the spa and then jump @!*% near naked into it.  The HCl in your stomach is strong enough to dissolve a horse shoe in fairly short order.

If the correct nomenclature is used, the original title of this thread refers to making nitric acid not making stain starting with nitric acid.  If you would like to know how nitric acid itself is made, just look up the "Ostwald process".  The US production alone amounts to some 20 million tons per year.  It is used for almost everything that is important to all of our lives on a daily basis.

Dave C

P.S.  If you are looking to buy chemicals, unless you need it for some very specific reason, don't buy "reagent grade" anything.  Reagent grade chemicals are of very high purity and are used for chemical analysis where it is important to know exactly what you have in the solution.  Reagent grade chemicals are many times more expensive than lower grades.  "Laboratory" or "Technical" grade is what you want for home made wood stains.

P.P.S  If you just throw steel wool or nails in nitric acid to make ferric nitrate stain and let it get too hot, you will make an inferior stain.  You must slow down the reaction in an ice bath and keep the temperature cool while the iron is dissolving.

[yip]

  dave; what do you mean by and ice bath? do you but the jar in a pan of ice?

[smallpatch]

OK, I get the idea that we are trying to emulate, our fore bearers........ But I'm going to dissolve the crystals......NOT mess with the acid!

Here, hold my beer, and watch this!!!

[rich pierce]

By making your own ferric nitrate using nitric acid, water and iron and over-staining (or not) with potassium permanganate, you can achieve a variety of tones.  Does anyone using the crystals of ferric nitrate have a test piece to show the variety of tones one can get?  Below are the results of weak, medium and strong batches of home brew with and without the potassium permanganate wash, which gives the purplish tone (D and F).

[davec2]

Yip,

To put this in a nut shell, I use a dilute solution of acid (one part concentrated nitric to 3 parts distilled water)......always add the acid to the water.  Never the other way around.  Place the beaker, or whatever you are using (pyrex glass is best....like a kitchen measuring cup) in a pan with cold water and ice cubes in it.  Add the iron slowly (I use short pieces of the the soft iron wire sold to tie up rebar, although I clean off the oil / grease with acetone before cutting it into small pieces.  Clean nails work as well.)  Just don't let the solution get too hot.  The heat will break down the iron nitrate and leave you with more sludge.  Keep adding iron until no more will react.  Pour off most of the liquid into a clean bottle.  Leave the sludge and any unreacted iron behind and discard.  Leave the top on the bottle (with the iron nitrate solution) loose for about a month before you close it up tight.  Keep the bottle in a safe place and not around anything you don't want to rust.

For a much better understanding of the chemistry and the how's and why's of genuine 18th century staining and finishing, I can recommend no better source than great guide written by William A. Knight and William R. Mende called "Staining and Finishing for Muzzleloading Gun Builders, Methods and Materials from 1750 to 1850". Not just stains but finishes, dyes, oil cloth preparation, etc., etc.) Not sure where to find a copy now, but Mad Monk may be able to put his hands on one.

[smart dog]

Hi Rich,
I make test pieces like that all the time for every rifle I make. I just don't save them.  My results for ferric nitrate crystals look exactly like your samples without the potassium permanganate wash.  My well water has iron in it and it produces very beautiful colors with ferric nitrate.  I typically dilute 1 part crystals to 3 parts water for shades a little darker than your C , 1:5 matches your C closely, 1:8 is similar to B.  I adjust my concentrations for each stock, making only enough for each gun, which gives me a great deal of control although all wood is somewhat of a gamble.  Also, unlike nitric acid, ferric nitrate can be safely dissolved in denatured alcohol to make a stain that does not raise the grain as much.  I really don't know why anyone would want to fool with nitric acid and iron given the availability of ferric nitrate crystals unless their objective is to recreate historical methods.

dave     

[rich pierce]

Thanks, Dave. Will give it a try. Would be good to not have a collection of jars on the shelf