First gun staining question

[James]

I used a 1:5 ferric nitrate solution (ferric nitrate crystals in ethyl alcohol).  I saw a change when blushing, it turned reddish brown with the curl visible.  I put on one coat of Chamber's oil and the curl doesn't pop out from the lighter wood the way I'd hoped.  My thought is that I didn't heat it enough.  Your opinion please.   Can it be made better?

[smart dog]

Hi James,
Always test a piece of wood first.  You can make the ferric nitrate stronger and that will darken it as well as simply add more coats. However, you have a problem now that you put oil on it.  You may have to strip off the finish because I doubt any stain will penetrate the oil very well particularly because it looks like you put it on pretty thick.

dave

[Mad Monk]

That stock will darken with age.  You will first see the curl darken and then the wood between the curl.  Curl that is barely seen now will begin to stand out more.

Maple wood contains tannic acid.  In the wood it remains water-soluble.  As the stock picks up moisture, from the air, and then gives it back to the air above the finish the tannic acid is leached out of the wood.  To be stopped at the "interface" between the finish and the wood.  It then reacts with the iron oxide to form a black iron tannate complex.  How fast it does this depends on the climate where you live.  Here in Eastern PA we have warm very humid summer months.  Then cold dry winter months.  In the hot summer months wood moisture content can go as high as 15% by weight of wood.  Then in a cold dry winter that may drop down to about 5%.  In between you have changes in humidity that will have moisture migrating in and out of the wood through the finish.  Really does not matter what type of finish you use.  The wood is going to "breathe".  The tannic acid becomes concentrated at the base of the finish.  Color depends on how much iron it comes in contact with.  The so-called "curl" is end grain and picks up a lot more iron than the wood sections between the curl where the grain is nearly parallel with the surface.

This reaction between tannic acid and iron has been known for at least 2000 years.  Described in writings by Pliny, The Elder, in Rome in 50 AD.  Iron compounds, such as ferric sulfate, and tannic acid had long been the common black writing ink until the introduction of the steel pen point around the end of our civil war.  Also  used a a fabric dye with cotton, wool or silk.


Give the stock 5 years and compare back to the photos you presented here.

Bill K.

[FALout]

Monk s right about the stain/finish looking darker as the stock gets older and is used as intended.  Some wood will just not cooperate with how you would like it to look.  I like the safer aspects of ferric nitrate, but like your experience, I had a stock come out very blond looking as compared to using aqua fortis.  I recoated and reheated the stock several times to get the curl to show more. For you, having already applied your finish that limits your choices on what you can do now.  Only you can decide if you want live with the results and use it as a learning experience.  The next step as already stated is to strip it and start over, but that can become quite the chore which could also damage any good work you've done, or even give you a chance to fix mistakes to stock structure.  As a side note, some don't use enough heat to get the chemical change to occur, but it is a fine line to not burning the edges/surfaces of the stock.  After your staining operation(before any finish is applied) you can wipe the wood with alcohol or acetone to get an idea of how it will look when finished.  If this was my rifle, I would leave it alone.  I usually like my stocks to be on the dark side, but once in awhile a blond is a nice change.

[James]

Thank you for the explanations and options.  I will leave it as it is.  Regarding the blondness, it is quite red in person, but looks blond in the picture while laying on red oak.  Funny how that works.

[Mad Monk]

Thank you for the explanations and options.  I will leave it as it is.  Regarding the blondness, it is quite red in person, but looks blond in the picture while laying on red oak.  Funny how that works.

How it looks in person versus the photos.  I am learning that digital cameras have limits on color rendition.

When I had done my original work on the nitrate of iron stain back in the early 1980s I had tried using ferric nitrate crystals from the lab chemical supply room.  Did not seem to give the same color effects as nitrate of iron prepared from nitric acid with iron.  I had the idea that the spent acid played a part in the colors produced.

I recently did a set of pistol grips with curly maple.  Tried ferrous sulfate as a source of iron.  Not as good as with vinegar and iron.  Ended up going with some old nitrate of iron stain left over from my rifle building days.