We work with a lot of Hawaiian koa wood. Some epoxy and urethane finishes bring out the natural reds and yellows in the wood while others don't. I have been told that certain acids (acrylic?) in the materials are responsible for this. We are relying on extensive trial and error to find the color enhancement we are looking for, but can't always achieve it. Can anyone tell me what is responsible for this color change, so that we might formulate our own topcoat with this in mind?
Different chemistry of products will have different results. If you want true natural colors then you want a product with very good "wetting" properties. Otherwise, I would use a slight dye on the pieces to pop some of the colors you want to get. It would add a step, though.
Bob Niemeyer, forum technical advisor
Your application rag is not that big. It should fit in the palm of your hand. It is commonly folded in the shape of a Persian/Middle Eastern pastry called a "hamantashen". Assuming that few people are familiar with this pastry, let's just say that the pad/rag is shaped like a small triangle.
In your other hand should be a cotton rag which is dampened with denatured alcohol so that you can blot any mistakes and also so that you can mottle the hand padding.
When hand padding, you want to mute the color edges for subtle effects of your color swath.
Just as a side note, neither pad stains nor hand padding techniques are mentioned in any finishing books at all.