Bringing out the grain in curly maple

[jbjewitt]

I should also add that it pays to have properly sawn and dried maple for maximizing figure.

[Danl8]

I cant help it - but I have to correct some of the above...…

Aquafortis is an old name for weak Nitric Acid HNO3
Ferric Nitrate is also know as Iron Nitrate Fe(NO3)3
The way I have used Nitric Acid is to apply it (without the iron) and then heat the wood. The problem with Nitric Acid is that it "stays put" in the wood.

I have never heard of using Ferric Nitrate on wood. I think that reference should have been to Ferrous Sulphate which will produce a brownish-gray look.

No actually not (sulphate comment).
A one to four dilution of nitric acid will produce a yellow to brown stain, but the addition of iron oxides make the stain reddish brown on heating. The reaction produces ferric nitrate, not sulphate. However, vitriol, sulpheric acid, will produce a yellow to dark brown stain and adding iron might have a similar effect, though i have no experience with that combination. The jar of ferric nitrate pictured anove accomplishes the same effect as brewing your own without the hazards of an exothermic reaction from the acids and iron oxides. Aqueous solutions of ferric nitrate produce the same ferrous/ferric ions in the wood after heating to form reddish brown to brown oxides. Vinegar, weak acetic acid, can do the same thing but the reaction takes a long time. The acids evaporate when heated. Some stock finishers use NaBicarbonate to neutralize, although not everyone agrees that is necessary. I've been doing AF stain for well over twenty five years, but only on curly maple, with the shortcut and rarely with nitric/hydrochloric acids for obvious reasons. Using a combination of stains, esp., analine water stains can be rewarding as well and always test first on scraps as wood chemistry/ mineralization etc. varies.

[jbjewitt]

Thanks for sorting that out. I had heard of the aquafortis brew used in the gun area but not furniture.
What sort of heat do you need with the ferric nitrate solution? I found with nitric acic alone it had to be pretty high, such as from a heat gun.

My comment about it staying put was purely empirical. All the samples I did 10+ years ago for a book smelled like Nitric when I cut them in half years later. I had used Sodium Carbonate to neutralize.

For musical instruments I still think dyes are the best way to go.