Couple more aqua fortis questions

[eagle24]

I made up a batch of aqua fortis using some 69.5% nitric acid.  I stained a piece of scrap from the stock I am planning to stain.  Now the questions.  First, the stain is cool.  Can I seal the jar tight now? or is there still the possibility of expansion from the gas? 

Next, the scrap piece that I stained turned out good (well sort of).  I stained it and gave it about 30 minutes to dry.  Then I applied heat using a hair dryer.  It didn't go dark enough so I used the stove eye for heat and it went much darker but the edges of the block turned black.  I can't tell if I actually charred them or they went blacker because of the end grain on the edges.  My questions are:

1. How is color effected by the amount of time the stain is allowed to dry before applying heat?

2. Is there a window of time that heat must be applied?

3. Can you apply heat and let the stock cool, then apply more heat later if you want it to go darker?

[Mike Gahagan]

I don`t think that it matters how long you wait to apply heat.I have waited anywhere from overnight to within minutes and seem to get similar results.I also use a heat gun that puts out 750 degrees and it seems to work well at that temp.It won`t scorch if you hold it too long or too close.It might take a little longer than a stove eye,but it works well when trying to get in areas like the ramrod channel and under the cheek piece and not char the higher areas.

[eagle24]

Thanks Mike.  I wasn't sure if I had actually scorched the block on the edges or that was just how the aqua fortis reacted to the heat.  I have a heat gun and will try it and see how it works.

[rich pierce]

I find it's important to make sure it's really heated "all the way".  Be persistent with it without scorching.  In other words let heat build up with time instead of getting too close to the heat source.  As long as you haven't neutralized yet, you can always heat again.  If you don't heat to completion you can get weird unpleasant greenish tinges (not at all the same as problems with chromic acid, chromium trioxide, which turn green over time).

Also depending on the dilution,  iron content and number of applications, you can get a lot of different tones from AQF on the same piece of wood.

 

[erdillonjr]

69% is too strong a nitric solution. Try 20% solution. I use 20% solution and let the stock dry over nite. In the morning I use a heat gun to heat the stock. Afterthe stock turns a uniform coller I neutrilze the acid with a baking solution . Water and baking soda and mix into a paste. Rinse with water to remove baking soda.. You must neutralize the acid or the stock will turn BLACK. Remember when mixing any acid you add the acid to the water not the other way around.  Ed

[eagle24]

69% is too strong a nitric solution. Try 20% solution. I use 20% solution and let the stock dry over nite. In the morning I use a heat gun to heat the stock. Afterthe stock turns a uniform coller I neutrilze the acid with a baking solution . Water and baking soda and mix into a paste. Rinse with water to remove baking soda.. You must neutralize the acid or the stock will turn BLACK. Remember when mixing any acid you add the acid to the water not the other way around.  Ed

69.5% was the nitric acid before I dilluted it and started dissolving the iron.  Sorry, I don't know why I even put that in the post.

What makes it darker or lighter?  Would a weaker acid content and less iron dissolved result in a lighter color? and stronger acid and more iron dissolved darker?

[rich pierce]

Some folks understand it; I don't.  I make several batches using different amounts of iron and let them go to completion.  Then wipe the stock with them diluted or straight.  Then use multiple coats, or not.

[Stophel]

If you turned it black, you scorched it.

Slop the stain on HEAVILY.  Let it sit for at least an hour.  Make sure it is dry.  The wood should be a greenish or grayish color. Then heat.  Repeat.  When satisfied all is well, then neutralize with a lye solution.

 

[eagle24]

If you turned it black, you scorched it.

Slop the stain on HEAVILY.  Let it sit for at least an hour.  Make sure it is dry.  The wood should be a greenish or grayish color. Then heat.  Repeat.  When satisfied all is well, then neutralize with a lye solution.

 

When you neutralize it, does the color change any?

[Stophel]

With lye, yes.  It will turn a more orange-red color.  I don't use baking soda, but I don't think it changes color with that.

I tried lime once, and it turned the color a rather dull brown, not very attractive, so I haven't tried it since.

[eagle24]

With lye, yes.  It will turn a more orange-red color.  I don't use baking soda, but I don't think it changes color with that.

I tried lime once, and it turned the color a rather dull brown, not very attractive, so I haven't tried it since.

Thanks!  I guess there is no substitute for experience with this stuff.  I'm gonna have to quit asking so many questions on here before I'm asked to leave.

[Bioprof]

My experience has been that the end grain turns dark no matter how much you heat it.

[billd]

The end grain and softer wood soaks up more so it will be darker, same with LMF stain.
 Every piece of wood will color different, some say it's how much sugar is in the wood, others say it how much tannic acid is in the wood, that reacts with the aqua fortis. 
Try it on the scraps that came off the blank your using. Sand it round like the forearm to get the most accurate results. This exposes more of the end grain.
Bill

[eagle24]

Well I learned a lot last night.  I cut 3 blocks from the same piece of maple and applied the aqua fortis stain to each of the three.  Immediately I started heating them with a heat gun and applied different amounts of heat to each block.  The one with the least heat has a very nice orange/red tint and is lightest, the one with the medium amount of heat turned more honey colored and a little darker (it is my favorite), and the last one I heated until it would go no darker.  It turned out a dark brown and black and looks good also, but went so dark it doesn't have the contrast the other two have.  I could live with either of the three colors/shades, but prefer the middle one over the other two.  At least now I have a little understanding how heat affects the color.  I'm going to do a little experimenting with the aqua fortis recipe and see how that affects the color as well.

[Ky-Flinter]

Also depending on the dilution,  iron content and number of applications, you can get a lot of different tones from AQF on the same piece of wood.

 

Rich,
What did you do to each of the sections to get such variation in colors?

-Ron

[eagle24]

I got similar colors to E, C, & D using the same stain, same wood, but varying the amount of heat applied.  As it went darker with more heat, it also moved from red to honey to brown.  I'd be interested to know how Rich achieved all those colors also.

Dan (Dphariss) mentioned in an earlier post that he "took what he got" in terms of color, understanding that each piece of wood was different.  One thing I notice with the aqua fortis stain is that none of of the colors look unnatural like you sometimes get with modern stains.

[Dphariss]

I made up a batch of aqua fortis using some 69.5% nitric acid.  I stained a piece of scrap from the stock I am planning to stain.  Now the questions.  First, the stain is cool.  Can I seal the jar tight now? or is there still the possibility of expansion from the gas? 

Next, the scrap piece that I stained turned out good (well sort of).  I stained it and gave it about 30 minutes to dry.  Then I applied heat using a hair dryer.  It didn't go dark enough so I used the stove eye for heat and it went much darker but the edges of the block turned black.  I can't tell if I actually charred them or they went blacker because of the end grain on the edges.  My questions are:

1. How is color effected by the amount of time the stain is allowed to dry before applying heat?

2. Is there a window of time that heat must be applied?

3. Can you apply heat and let the stock cool, then apply more heat later if you want it to go darker?

Hair drier won't work.
The stock needs to be well heated with deep penetration of the heat. ALL the stain must be reacted even the stuff that has soaked into the wood.
I use a paint stripper gun on *low* and keep it MOVING or it WILL char edges.
I bring the heat wood fairly slowly over large areas. I like the wood to be very warm/hot to the touch
Its possible to use electric stove burners or radiant heat  sources but they ALL require care to prevent scorching. This is why practice pieces are nice.
The color will change when its oiled, though synthetic finishes are often too "transparent" to do this well.
If you add metal to the stain do not cap until all reaction stops, I.E. the metal is gone or the acid depleted.

Dan

[Stophel]

My experience has been that the end grain turns dark no matter how much you heat it.

I have NEVER seen this.  That's one of the beauties of Aqua Fortis.  It doesn't cram the grain with pigment.  It changes the color of the wood.




Note all the end grain at the front and rear of the cheekpiece, nose of the comb, etc.  It is just as bright and clear as the rest of the wood.  Now, if I had finished it with oil, then yes, it would be darker in these areas.

I have also never gotten any variation in color on any one particular piece of wood.  The stain just does what it does. (Now, you can put the stain on, and heat it right away, without letting it dry, and you get a screaming bright orange color, but otherwise, no variation.)  Now, I have never fiddled with the amount of iron.  I just put it in until it stops "dissolving".

[Stophel]

[

Hair drier won't work.
The stock needs to be well heated with deep penetration of the heat. ALL the stain must be reacted even the stuff that has soaked into the wood.
I use a paint stripper gun on *low* and keep it MOVING or it WILL char edges.
I bring the heat wood fairly slowly over large areas. I like the wood to be very warm/hot to the touch
Its possible to use electric stove burners or radiant heat  sources but they ALL require care to prevent scorching. This is why practice pieces are nice.
The color will change when its oiled, though synthetic finishes are often too "transparent" to do this well.
If you add metal to the stain do not cap until all reaction stops, I.E. the metal is gone or the acid depleted.

Dan

I used to have an old hair dryer that would get hot enough.  It quit on me, so I had to try a new one, which didn't get hot enough.  So, I got the heat gun.  The few times I tried using a stove plate, it worked very well.  I think radiant heat probably works better without scorching so much...

[eagle24]

My experience has been that the end grain turns dark no matter how much you heat it.

I have NEVER seen this.  That's one of the beauties of Aqua Fortis.  It doesn't cram the grain with pigment.  It changes the color of the wood.

Note all the end grain at the front and rear of the cheekpiece, nose of the comb, etc.  It is just as bright and clear as the rest of the wood.  Now, if I had finished it with oil, then yes, it would be darker in these areas.

I have also never gotten any variation in color on any one particular piece of wood.  The stain just does what it does. (Now, you can put the stain on, and heat it right away, without letting it dry, and you get a screaming bright orange color, but otherwise, no variation.)  Now, I have never fiddled with the amount of iron.  I just put it in until it stops "dissolving".

Chris, I am confused by your saying you have never gotten a variation on one piece of wood.  I got a variation dependant on the amount of heat applied.  I heated one piece to a nice medium color with a heat gun and put some finish on it so I could really see what it looked like.  It looks good, but I definitely did not heat it to a point that it went as dark as it would go.  Another piece I really poured the heat to with the heat gun (probably more than I would be comfortable with on my stock although it did not char) and it went really dark.  Are you saying you heat until it goes as dark as it will go and it is what it is?  If that is the case, I would see how you don't get any variation.  If I need to fully heat it, then my mixture or wood is turning out darker than I want.

[Stophel]

I heat it until it fully changes color.  Goes from gray directly to orange-brown.  I never get any graduated color change.  It does what it does and that's it.  If I heat it any further, it does nothing...except burn.  Definitely gets darker then!  If you've seen "The Gunsmith of Williamsburg", you've seen exactly what I see.  Heat it, it turns color, and that's it.

I "aged" this gun here.  The darker areas are actually burnt with the heat gun.


Years ago I quit trying to vary the color I got with A.F.  NOTHING I did made any difference.  Couldn't get a lighter color, couldn't get a darker color.  Strong solution, weak solution.  Mattered not.  Don't put enough heat on it, it simply will not turn color.  Too much heat, well, it burns the wood.  The only thing I found out is that if the solution is too weak, it simply will not color well.  There is a certain point of strength that is required for it to function.  Beyond that, it seems to make no difference.  Further applications do not make it darker either.  I have to do at least two, just to make sure my color is even, and after that, I could apply it a dozen more times (literally) and the color will not change.  I end up staining SEVERAL times, since I have a hard time seeing imperfections in the wood when white, and when I stain it, bingo, there's a spot I have to fix, so I have to stain several times before I am satisfied with the surface of the wood.  By the way, after 4 or 5 applications, the wood gets saturated (I guess) and it doesn't want to absorb any more.  The stain just beads up on the surface, but will eventually soak in.

I have no clue how Rich could get all those different colors from Aqua Fortis.