Aquafortis and stains

[490roundball]

An order from Track of the Wolf arrived today with a bottle of their Aquafortis - and instructions.  I actually read them (slow night) and was surprised to see a statement in there that a stock treated with it will not accept a stain ( difficult or impossible).   

Just curious if anyone has had a problem with stains after Aquafortis.   I stained a rifle after using Aquafortis (didn't read the instructions then), and it turned out just fine.   I always try a number of finishes on scraps before the finished product, so I'll try this out as well.  But I was just curious about the statement, or if maybe it is just this formulation that has the issue.  Guess we will find out this weekend  .

Rick

[Ed Wenger]

Rick, I don't think you'll have any problem with stain over the AQF.  I've used the same stuff and haven't had any problems, maybe I should have read the instructions as well...
Like you said, test it first and see how it goes.  Let us know how you make out.

Ed

[Mad Monk]

The explaination that the stock would not accept another stain after having been stained with the Aquafortis may not be the most accurate way to explain the situation.

They have no control over how the end user uses their stain.  Or what sort of other stain the user will apply over the Aquafortis stain.

The organic dyes used to stain a lot of stocks are sensitive to the pH of the surface to which they are being applied.  Some red dyes will turn blue if what they are applied to is alkaline.

Brown and black dyes are not much of a problem in regards to pH sensitivity.  A lot of the red and yellow dyes are pH sensitive.

So if the gun builder does not do too good of a job in neutralizing the acid left by the Aquafortis the dye applied afterward may not be the color desired.  The same might be true if the builder gets carried away in neutralizing the Aquafortis with a strong caustic rather than a mild caustic.

The builder usually would have no knowledge of this sometimes pH sensitivity of various organic dyes and blame the Aquafortis for strange colors.

To give an example of this organic dye pH sensitivity.
When I remodeled the first floor the wife wanted a desert sand color paint.  So I had the hardware store mix me up several gallons of PPG acrylic latex paint in desert sand color.  After about 4 years on the walls the paint turned a weird purple color.  The red dye used to give the slight pink tint in the deserat sand color acted as a pH indicator.  As the acrylic latex paint aged the acrylic polymer started to break down and release acrylic acid which is the base stock from which the polymer is made.  The paint film went from an alkaline state to an acid state.  The red dye used to give the pink tint is a blue color when acidified.

So there is a chance that when the builder goes to "kill" the acid left by the Aquafortis there could be some variation in the process that effects the color of the dye being applied to give additional color.

Bill K.

[490roundball]

Thanks Bill

That makes sense.  When I stained the other rifle, I neutralized it with baking soda and water and applied LMF Lancater maple and a light wipe with another LMF stain.  And that color has stayed stable for several years.  I'll be following the same basic procedure this time (just a bit lighter color) so I will just make sure to treat the test scrap and final finish the same way.

Rick

[t.caster]

So if the gun builder does not do too good of a job in neutralizing the acid left by the Aquafortis the dye applied afterward may not be the color desired.  The same might be true if the builder gets carried away in neutralizing the Aquafortis with a strong caustic rather than a mild caustic.

Bill K.

Too little....too much? How can we test it? I probably err on the side of using too much BS in water.

[Mad Monk]

Too little....too much? How can we test it? I probably err on the side of using too much BS in water.

With the commercial Aquafortis it is best to stick with baking soda.  As caustics go it is a mild one.

When I worked with nitrate of iron stain I played with different caustics to get different color variations.

With the baking soda you know you have all of the free acid "killed" when the surface no longer foams with the baking soda solution.

[Stophel]

Alright, I'll say it...if you stain properly with AF, you don't need any other kind of stain on top of it.

 

[PIKELAKE]

Stophel said it, "If you stain properly........". I found out the hard way. One day because of the weather I decided I wood Aqf  a stock at my bench in the basement under flouresent lights. I hit it with my heat gun and it looked ok. I then used a bakin soda wash to kill the AF and set it aside to dry. The next day I reviewed the stock in natural light and was taken back by the green hues radiating from the wood. I washed the stock with plenty of water and tried another application of AF. Could not get the green out leading me stain over the AF. The stock ended up looking ok, but not what I was looking for color wise. The moral of this story is this," I will never again apply AF to wood under artificial lights". I think once you nutralize the wood with the soda it is very hard to get the stock un-nutralized enough to get the AF to work...I think

[Dennis Glazener]

I then used a bakin soda wash to kill the AF and set it aside to dry. The next day I reviewed the stock in natural light and was taken back by the green hues radiating from the wood.

Is there a chance that you did not apply enough heat? The only time that has happened to me was when I didn't get the wood hot enough, left greenish color in several places. I went back and held the heat gun on those spots until they darkened to match the rest of the wood.
Dennis

[PIKELAKE]

Dennis, I believe you are right, I did not apply enough heat. I blame this on  the darn lights. I got got a false impression that my blushing was complete, when in reviewing the stock under natural light, I found to my dismay that the job was not done. I usually do this AF business in garage in the light of day and never had this happen before. Live and learn. And they did all this gun building with oil lamps? I never would have made it.

[Mad Monk]

I see in one of the posts about the use of a heat gun.

When I read the thing in Calvin Hetrick's book, "The Bedford County Rifle and Its Makers" I saw his description of how Dolfus M. Drake stained with the nitrate of iron stain.
He heated the stained stock over the forge fire.  That would give more radiant heating of the wood's surface versus heating by hot air.

I have an idea that a heat gun that blows hot air might dry the stain solution out before it really gets a good chance to work on the wood.

So you might want to try some other source of heat.

When I was still doing stocks with nitrate of iron I would apply the stain solution and then use one of the large heating units on the wife's kitchen range.
Now of course she knew the script here and as soon as I hauled out the bottle of stain she would simply go do a little shopping to get out of the house.

I did find that I could not set the heating unit on the max bright red coil setting lest I burn some of the fine edges of the stock.  But at the medium setting it gave good control over the heating of the wood and the changes in the color patterns brought about by the heating.

[Dphariss]

I see in one of the posts about the use of a heat gun.

When I read the thing in Calvin Hetrick's book, "The Bedford County Rifle and Its Makers" I saw his description of how Dolfus M. Drake stained with the nitrate of iron stain.
He heated the stained stock over the forge fire.  That would give more radiant heating of the wood's surface versus heating by hot air.

I have an idea that a heat gun that blows hot air might dry the stain solution out before it really gets a good chance to work on the wood.

So you might want to try some other source of heat.

When I was still doing stocks with nitrate of iron I would apply the stain solution and then use one of the large heating units on the wife's kitchen range.
Now of course she knew the script here and as soon as I hauled out the bottle of stain she would simply go do a little shopping to get out of the house.

I did find that I could not set the heating unit on the max bright red coil setting lest I burn some of the fine edges of the stock.  But at the medium setting it gave good control over the heating of the wood and the changes in the color patterns brought about by the heating.

Hi MM
I have had pretty good luck with the paint stripper gun on LOW. On high it puts too much heat on and can scorch edges or carving. Even on low it heats the wood well if care is used and once the thing is warmed up produces radiant heat since the diffuser plate gets red hot. I usually let the stock air dry before heating to make sure I get all the penetration likely to occur. It gets kinda green.
 Before


After heat and one coat of oil.


I have used elec. stove burners with the same results you note and even put them in the corner behind the wood stove in winter. Slow but works really well if the stove is pretty hot and stock is turned and rotated properly.

Dan

[Dphariss]

Alright, I'll say it...if you stain properly with AF, you don't need any other kind of stain on top of it.

 

My sentiment exactly.
And...
Why use a HC stain then color it again with something that might turn blue in a couple of years?
Form what I read here many of the modern stains are pretty labor intensive when trying to get something that looks like AF. 2-3 different colors used etc etc.

Dan

[Stophel]

Stain AT LEAST twice to ensure that you have sufficient AF in the stock, and that will get rid of the green.   

[Karl Kunkel]

Curious novice question. 

Do you heat the stock while still wet?  Or, do you let it air dry first, then hit it with heat?

Stophel, do you heat between applications, or is it two coats in succession, tehn heat?

[rich pierce]

I let dry 30 minutes.

[Rich]

I just finished a stock with Track"s Aquafortis. On my test piece, I used aquafortis and then tried a couple of stains. One Laural Mountain and the other a leather dye. Each stain worked over the Aquafortis but the Aquafortis alone looked the best. The stains muddied the curl. On my test piece, I followed the instruction sheet Track provided. It does not mention neutralizing. It only suggests applying a boiled linseed oil based finish. I used Tried and True Oil Varnish on the test piece, the color has been stable for over a month without neutralizing. I guess the oil alone might be enough to stop the darkening. 

[Stophel]

Slop on the AF heavily, definitely let it dry (if you heat it right away, you'll probably get a screaming orange color).  For sugar maple, I let it sit for at least an hour.  For red maple, a half hour is usually necessary (or as long as you need for the stock to be fully dry).  Then heat.  Repeat.