Bill,
Good question.
A traditional stain for maple is nitric acid saturated with iron (nails, filings, scrap) then diluted. Because of the availability of ferric nitrate from chemical supply houses, actually making the stuff yourself is not required (though some makers do so).
I have applied it to a stock that has been whiskered to raise the grain and then sanded to final condition. The ferric nitrate solution is water based so it will raise the grain if that has not been done.
Depending on the depth of color, one or several applications of stain can be used. Test on a scrap of the stock wood to determine the performance of the stain on the particular wood. I don't know all the factors that influence the way the wood takes the color, but there is some variability in result.
When the stain dries and before it is heated, the color is a greenish gray and you will fear you have ruined the stock.
I use a variable heat gun to warm the stock and evaporate the water. This leaves the color in the stock. Be careful not to heat the wood and char it, which can happen quickly if too much heat is applied to a delicate area. The vapors are pretty strong and I suspect harmful so have good ventilation. It is amazing to watch the color change from the sickish green/gray to an auburn reddish brown.
I have neutralized with baking soda, but others do not.
The finish will darken the wood, so you may want to rub back the finish to lighten it a little.
Hope this is what you wanted.
Larry Luck
PS, the stain also works to antique powder horns.
