Building the BP trade rifle from a TOTW kit

[Claven2]

Now that the stock is sanded to 400 grain to remove some of the loose fibres, we need to start darkening it. There are all kinds of shortcut products, as I like to call them, but I'm not a fan, so let's do it like they did a couple hundred years ago.

First of all, you need to locate some 70% concentration nitric acid, some places it's called "assay acid" as it's used in the assay of precious metals. It's not as easy to get as it used to be since apparently there are terrorist-like things you can do with it in quantity??? I had a buddy (thanks Brewster!) who works with the stuff and he provided me with the right dilute solution (1:4 acid to purified water). You paint it onto the stock (wear protective gloves!) and allow it to mostly dry. In the old days you would use a heat source like an oil lamp or candle to slowly heat the surface of the stock until the acid oxidizes some of the chemicals in maple, but you can take a shortcut here and use a heat gun with a concentrator tip. It's way faster and you are way less likely to accidentally char part of the stock - be especially careful of thin areas!!!!. when it turns color, it does so very abruptly and becomes a mellow yellow-reddish tint like so:





No, that's not wet, that's the color it becomes DRY. As an added benefit, if you had bits of iron or steel dust in the grain pores that turned into a greyish bunch of stain spots on your stock when you had wet it to raise the grain (it doesn't sand off), the dilute acid chemically eats the stains away 100% leaving only any residual inletting black on the wood. An added bonus, and also why you don't need to worry about any grey water/iron stains. In case anyone cares, those stains are dissolved iron or steel oxides from chemical reactions with wet tannic acid that was in the wood.

Now need to neutralize all that acid so that it doesn't work on the stock for the next decade and doesn't pit your steel parts when you assemble the rifle. Mix a tablespoon of baking soda with warm tap water and paint it onto the stock. Allow to mostly dry and repeat. This will kill as much of the acid as you need to worry about. If we stopped here and oiled hte stock, it would be a nice chestnnut brown, but it would not look period. It need a little more purply-red. More on that later...

Here is a pic of the stock wet with soda water. This is roughly how it would look if oiled today. Really not that bad.



There will be a few new grains that will have raised from all this work. Don't worry about it. If you did a decent job removing the worst of it when you wet the grain the first time and re-sanded, what remains will come off when we oil the stock using a fine steel wool buffer pad later on.

More to follow on traditional stock finishing

[tbonesmith]

Never heard of that staining method, will have to try it on something. Very impressive!

[Claven2]

If you don't already have a copy, try purchasing "the Modern Kentucky rifle" by RH McCrory. I beleive he is long since deceased and wrote the book in the early 1950's, but it's still one of hte best step-by-step references out ther eon how to build a longrifle using traditional methods. This is one of the processes he outlines.



Most of the modern stuff like Aqua-Fortis or Chromium Trioxide are modern chemical treatments designed to replicate these older and more time-consuming methods. When I start the next step, we will turn the stock almost black, but it will retain these brown-red undertones from the Nitric Acid staining.

[gew8805]

.................................
Most of the modern stuff like Aqua-Fortis or Chromium Trioxide are modern chemical treatments designed to replicate these older and more time-consuming methods. When I start the next step, we will turn the stock almost black, but it will retain these brown-red undertones from the Nitric Acid staining.

Excellent work Claven, you are doing well.

I do have to say though that Aqua-Fortis is the alchemical nomenclature for nitric acid and is commonly available, at least here in the US. Do a Google search for "Purchase Nitric Acid" and the options are many. It is commonly used in staining maple, whether for longrifle stocks or furniture . It can be had from any company dealing in stains for longrifles (Track of the Wolf, Stonewall Creek Outfitters and many others) as well as some who deal in traditional stains and paints for the traditional furniture builders. It is usually available mixed with 2 parts nitric acid to 1 part distilled water - a 50% dilution but the 25% dilution you mention also works well and does allow more opportunity for control.

Chromium Trioxide on the other hand had much popularity at one time ('50s - '70s) but has fallen seriously out of favor since it will, with time, age to a green cast when used on wood though it usually starts as a nice shade of brown. Aqua-Fortis is completely traditional and is widely used for maple and other woods as well but it will darken walnut and cherry too much unless used in low concentration.

May I recommend two excellent books that have a great deal of information on building the longrifle? One, my personal favorite is “Recreating the American Longrifle” by Bill Buchele with updates by George Shumway and Alexander. This book is a classic written by Buchele in the late 1960s. Also, there is “Art of Building the Pennsylvania Longrifle” by Dixon, Ehrig and Miller. Both are commonly available and widely expand on McCrory’s excellent early work.

[Claven2]

Thanks for the book recommendations

I actually was not aware that Aquafortis is nitric-acid based. I do know that TOTW has been out of stock on it for almost 2 years now (I have a standing notification for it) and I've not found anyone in the US who will ship NA to Canada. Here in Canada, it's sale is very regulated.

[gew8805]

Thanks for the book recommendations

I actually was not aware that Aquafortis is nitric-acid based. I do know that TOTW has been out of stock on it for almost 2 years now (I have a standing notification for it) and I've not found anyone in the US who will ship NA to Canada. Here in Canada, it's sale is very regulated.

Sorry to hear that, I thought that might be the case. If they will work with you, you can try Stonewall Creek Outfitters, they have it at:

Finishes and Stains

They are a good and reliable company but like most sellers they will be aware of the law and may not ship if Canada has strict regulation. Track may be the same when they are back in stock. That being said, the Wahkon Bay Outfitting Co. items are high quality. Good luck and looking forward to seeing the next instalment.

[Claven2]

It' not too big a deal, I have a near-future supply of dilute Nitric acid now anyhow

[Claven2]

So next we darken the finish down with a solution of potassium permanganate mixed with water. Potassium permanganate can be bought at higher-end aquarium supply stores as some aquarists use it for something or other. It comes as small purple crystals that readily dissolve in water. I mix about a half teaspoon in an ounce of water.



Paint it onto the stock, let it almost dry, then paint on another coat. I'll be doing this several nights in a row until I have it almost char black when dry. It lightens SIGNIFICANTLY as it dries, so this will take a good many coats.



Still wet and saturated:

[Claven2]

Once you have enough potassium permanganate on the stock so that it looks charred/burnt, you then hand-rub boiled linseed oil into the whole thing. This is what it looks like after staining and oiling - almost black.



Next take some extra-fine steel wool, soak it in boiled linseed oil and vigorously rub the stock until the desired look is achieved. Be careful around corners and edges - it you rub those too hard or are not careful, the edges will bee too light. I try to leave it darker in areas where the gun would not see wear in service. This gives the stock and older look, similar to an original.

So far I've buffed the area up to the lock flats. The steel wool removes any left over raised grain or imperfectly sanded areas making the wood glass-smooth. Later after the whole stock is wooled, several hand-rubbed coats of BLO will finish the stock off.

[Claven2]

Stock fully buffed down and polished now, 2 coats of BLO applied. I suspect I'll need another 6-8 cots minimum before I get the gloss I'd like to see, but here it's wiped dry and photos taken in overcast sunlight. Not bad IMHO. I did take the finish thinned at the wrist and at the front hand support to give the illusion of age and wear.









And don't forget to break off a small piece of wool and polish the inside of the ramrod channel!