How ya doing John. Iron buff has been used for centuries to darken wood. The way I make it is to take a pad of 0000 steel wool, rinse the oil off with lacquer thinner, tear it into chunks and put it in a closed jar with a pint of white vinegar. The acid in the vinegar dissolves the iron in the steel wool. The longer you let it set, the more iron is in the solution and the darker it will make your wood. I found this in a magazine and am just trying it out on a run of clocks I am building. When you are ready to use it, you strain it through an old tshirt and then through a coffee filter to get rid of any partially dissolved portions of steel. Brush it on. Like I said, it is a chemical reaction, leaving a completely even finish. I don't know about sanding and finishing, but suspect that most sanding should be done before applying. I don't know either how it will take a finish, but will find out on these samples. If you go to the forum, I will keep posting updates. Forum name iron buff.