An Aqua Fortis Question

[QuanLoi]

About thirteen years ago I built a rifle and used Aqua Fortis (I believe supplied by Wahkon Bay) to stain the stock.  I didn't dissolve iron into it and, after heating, achieved a rich brown color.  Is this the same brand of product that builders on this forum dissolve iron into?  I notice that a new bottle I obtained contains ferric nitrate and ferric chloride.

Also, is it necessary to remove brass furniture before applying Aqua Fortis?  To be honest, building a gun after so long an hiatus requires one to learn old skills all over again.   I sometimes look at my old guns and say to myself..."now, how did I do that?"

Thanks in advance...

[Dphariss]

I think ferric chloride is a result of the Hydrochloric acid content. But I am not a chemist.

Dan

[Dr. Tim-Boone]

Aqua Fortis stain is Nitric Acid and Hydrochloric acid with iron dissolved in it.. it then becomes a solution of ferric Nitrate with some ferric chloride.... that is the stain.  Wakhon Bay and others sell it in this form. You can also buy Ferric Nitrate crystals and dissolve them in alcohol or water and make your own solution.....

I guess some people use straight nitric acid as a stain... or so they say.... I don't understand that..... but I think they confuse nitric acid with Aqua Fortis or Ferric Nitrate solution............

Yes I would remove all brass before staining with Aqua Fortis.... I don't suppose strictly speaking that you absolutely have to but it allows the stain to get into the wood under the brass...but then I normally seal the wood with varnish before installing the brass and putting finishing coats of varnish on..... Hope that helps

[tallbear]

Don't mean to disagree with Dr. Tim but here is my take.

Aqua fortis is Nitric acid,water with iron dissolved into it.If the you dissolve iron until the acid is spent there is no need to neutralize or remove brass componets when staining.

Aqua regia is Nitric acid,hydrochloric acid,water with iron dissolved into it.Again if the acid is spent there is no need to neutralize or remove brass componets when staining.

Wahkon Bays Aqua fortis is really Aqua regia as hydrochloric acid and Nitric acid when it's made.I've also found that Whakon Bays tends to be very acidic(which means the acid is not totally spent).When I used Whakon's product it continued to darken over time and it will discolor brass.So if your using Whakon Bays product you may wany to neutralize.

If you are using Ferric Nitrate crystals the acid is also spent so there is no need to neutralize.

Mitch

[James Rogers]

Mitch,
A most concise and correct post.
James

[Dr. Tim-Boone]

Mitch, no disagreement, I just wasn't complete. Your explanation is my understanding as well.  Not sure why Wakhon bay misnames their product.

[bgf]

Dr. Tim,
Because who would buy "Aqua Regia" ?  Also, I wonder if the Wahkon bay product is designed to work for browning as well, in which case a little hydrochloric and leaving the mixture on the acidic side might allow it to work better/faster?

[Joe S]

Aqua fortis, literally strong water, is nitric acid. 

Iron dissolves in nitric acid and forms iron nitrate or as it is also called, ferric nitrate.  We call these ferric nitrate solutions aqua fortis, but that name is in fact a misnomer. 

Apparently this misnaming may date back at least to the late 1700’s, at least judging by TOF’s post.  But if they said aqua fortis, I think is most likely that they were referring to a nitric acid iron solution, and not an aqua regia iron solution.  These acids have both been known since the 1300’s, and their reactions with metal and wood were understood long before the 1700’s.

If Wahkon Bay’s aqua fortis is really aqua regia, then it is misnamed.

[tallbear]

No matter what you call it if it's still acidic neutalize.If the acid is spent there is no need to neutralize.

Mitch

[Dew]

I have a bottle of wahkon bay aqua fortis but I havn't used it yet and I am not all that familiar with it. So from what you all are saying should I put some steel wool in it or is it ok as it is? How do you know if its right? Thanks, Dew

[oakridge]

If you want to make sure all the acid is spent, just add a little iron and see what happens. I don't think it will hurt anything. If it dissolves more iron, you know it was still somewhat acidic. I would rather do that and not have to neutralize it after application. I wouldn't use steel wool as it comes from the hardware store. I think it has oil on it.

[Dphariss]

I have a bottle of wahkon bay aqua fortis but I havn't used it yet and I am not all that familiar with it. So from what you all are saying should I put some steel wool in it or is it ok as it is? How do you know if its right? Thanks, Dew

Degrease the steel wool. Denatured alcohol will work.
Personally I would order some Ferric Nitrate crystals and make stain from that.
The iron is the stain, not the acid.

Dan

[PPatch]

Last August I put a skein of 0000 steel wool through a dishwasher cycle and then into a pint jar filled with regular white household vinegar. I have freshened the vinegar once since, about a month ago. What I have now is a greenish tinted solution with lots of steel wool remaining, there is a muddy looking slush in the bottom of the jar. It looks as if it is not active judging by the lack of bubbles.

A little over a month ago, not liking the looks of the steel wool solution, I decided to start over and searched the outbuildings for old iron, there must be a ton of it out there. I put just a few ounces of rusted nails and what I took to be old wrought iron in another pint jar and added the same vinegar used with the steel wool. That jar is bubbling along nicely and the vinegar showing a brown reddish tint.

Am I on the right track with the second try?

Also, just wondering – With the Wahkon bay, or any other such acidic solution – is there a way to simply neutralize it before putting it on a stock (other than adding iron and waiting).

Thank you.

[Dphariss]

I have made ferric nitrate from old wagon tires, steel wool and modern nails the color is identical. I suspect that the ferric acetate does not care where the iron comes from either.
It will have about the same effect on maple as ferric nitrate. The down side is that it takes too long to make. Ferric Nitrate can be started at 10 AM and be ready to test on maple that afternoon.
Makes a lot more sense from a gunmakers standpoin. Nitric Acid was very common in Colonial times so there would be no reason to make the vinegar stain if someone was making guns on any kind of a schedule.

Dan

[QuanLoi]

Regarding the necessity of adding iron to the Wahkon Bay Aqua Fortis product:  The rifle I built stained with that acid about thirteen years ago exhibits a beautiful rich brown color with good contrast in the curl.  I used the acid as it exists right out of the bottle and didn't add any iron to it.   I've also stained several maple knife scales with WB Aqua Fortis as is.  In every case I neutralized with a solution of baking soda.  

If the current product is similar to the WB AQ I used in the past, I see no need to add iron... (Not knowing if the new product is the same as the old, I will test a scrap piece of stock before applying it to my current build.)

My opinion of course...

[WadePatton]

Regarding the necessity of adding iron to the Wahkon Bay Aqua Fortis product...

it's only necessary to add iron if you want to eliminate the need to neutralize the acidity with a base (baking soda).  As i understand it there is absolutely no benefit to using the solution (on wood*) while it is still acidic. 

As Dan says the iron is the stain.  The acid is only for making the iron into a handy solution-that's why it's no big whoop which acid is used to "solve" the iron.

*but that it could be used to brown metal in the acidic state.

do as you please.

[Rick G.]

So can you use aquafortis to brown the barrel as well? Or would a regular browning solution be better? 

[Rolf]

Last August I put a skein of 0000 steel wool through a dishwasher cycle and then into a pint jar filled with regular white household vinegar. I have freshened the vinegar once since, about a month ago. What I have now is a greenish tinted solution with lots of steel wool remaining, there is a muddy looking slush in the bottom of the jar. It looks as if it is not active judging by the lack of bubbles.

Patch,
If your steel wool is pure iron and it's clean, your problem is probably the iron solution is to consentrated.Hence the sludge and color. I'd try to dilute it with vinegar.I made my stain with liberon steel wool(woodworking wool, not dish washing wool) and the cheapest available white vinegar 7%.


In this picture you'll find the vinegar used (Eddik is norwegian for vinegar) and the steel wool.
The glass on the left is the undiluted stain. The glass in the middle is the stain diluted half and have with vinegar. The glass on the rigth is 1 part stain and three parts vinegar. This is what I used on these pistols.


Here is a link to the steel wool I used http://www.rockler.com/product.cfm?page=1436

Best regards
Rolf

[Dphariss]

So can you use aquafortis to brown the barrel as well? Or would a regular browning solution be better? 

If its acidic enough it can work well I have found that Wahkon Bay Brown and Stain makes a good rust blue solution.

Dan

[KentSmith]

Aqua Fortis = nitric acid
Aqua Fortis Stain by Wakon Bay et al = a stain obtained primarily by adding iron filings to diluted nitric and hydrochloric acid solution  and is basically a ferric nitrate solution  w/some residual acid and should not be confused with aqua fortis. This should be neutralized with some base as it will in time darken the wood.  I don't see the pint in adding more iron to this as it is easier and faster to neutralize with a paste made with baking soda and water, however and I have other things to do.

You can make the stain using either ferric nitrate crystals and water or disolving iron in a diluted solution of nitric acid.  The first more fun than the latter.  The latter way you should netralize with wood after staining to be safe less the wood darken and I don't care if you think the solution doesn't react with iron anymore or not.  But its your work and time so do it your way.

Take a look at the subject in the archives as this discussion has been held numerous times in the past.  I think people make the whole thing a lot more complicated than need be

Get any of these chemicals from Antec Chemical Supply in Louisville, KY.  Order online, pay the haz mat fee and find a place to store the stuff until you use it all up.  Ferric nitrate - fairly safe to store, nitric acid is another issue.  Scares me straight but I have a liter sitting there that will last me for life.  I need to make arrangements less I do not wake up tomorrow and someone else has to clean out the shop.

[David R. Pennington]

When I built my first rifle no one had any commercially available "aqua fortis" so I researched how to make it. I found nitric acid readily available at a local commercial chemical supply but I had to produce my bussiness license before they would sell it to me. I cut it 3 to one with water and dissolved iron filings and steel wool in it untill it would "eat" no more. Much caution should be used with the raw acid as it is very strong. Wear protective clothing and I mixed it outside in a stoneware jar. I ended up with about 2/3 of a pint jar of rusty brownish red looking stuff about the consistancy of skim milk and have stained several rifles and lots of other smaller projects. I usually use heat on the wood after the stain is applied and havn't seen a need to nuetralize. I havn't found anything I like better on maple, and find it gives a really nice oldtime look to hickory hawk handles etc...,.
I'm almost out of the original batch and will need to mix a new one for the current build, but I still have enough of the acid to last for a long time.

[Long John]

This question was covered extensively a couple of years ago.

The brown color in the stock is a mixture of iron oxides.  Iron makes both ferrous, ferric and ferrosoferric oxide.  Each of these oxides will form hydrates  The mixture of iron oxides and their hydrates result in teh brown color.  The relative concentrations of each of the oxides will affect the color so you can coax a rededer or blacker color out of the same stain solution but it is an art and relies on some luck.

The acid is the means by which we make the iron soluble so it can soak into the stock as a solution.  Commercial stains are generally ground-up, powdered clays and iron oxides.  The do not enter the wood fibers as a solution but rather as a suspension.  Consequently you do not get the depth of color.

Almost any acid can serve as the vehicle for getting the iron into solution as long as the acid can be vaporized so that it leaves the iron behind in the wood.  Acetic acid (vinegar) is one acid that vaporizes at room temperature.  Nitric acid vaporizes at a higher temperature and needs applied heat.  Hydrochloric acid will vaporize but at temperatures that are near the char temperature of wood.  Iron chloride comes in two forms one that is black and one that is green.  Consequently I would avoid anything that includes hydrochloric acid as a stock stain.

I am like Rolf, I use vinegar as my acid.  I also dilute the stain with vinegar to enhance the red tones as much as I can.



This rifle was stained using vinegar and iron.

Best Regards,

John Cholin

[Dr. Tim-Boone]

Hmmm  vinegar and Ferric Nitrate Crystals???  I wonder?

[bgf]

Dr. Tim, What a great idea -- must be I thought the same thing !

Rolf, Long John,
I've had vinegar/iron brewing for almost two years and have yet to achieve anything red.  I keep cutting it with vinegar and trying, but I always end up with grey (which is easy to achieve pretty much immediately with vinegar and iron mixture).  From reading and re-reading, it seems like I still have too much iron in solution (used filings from under the vise).  From Rolf's picture (thanks!), it appears I need to dilute w/vinegar even more.  I've been using it as a "toner base" on wood to whisker the wood, bring out the figure, and then darken the tint of LMF "stains" above it; that works pretty well, but I'd still like to achieve something like red with vinegar/iron alone.  You two give me some hope.

[PPatch]

ROLF; Your post is very helpful, thank you sir! I will experiment with dilution. Those pistols are gorgeous.

LONG JOHN; Your post is also quite helpful, Thank you for the succinct sum up and picture of a beautiful rifle stock.

Dr. TIM; I was wondering the same thing, a mixture of the two... 

dave