Cratering is the careful sanding of a surface to expose layers of paint or other materials that may have been applied to it. The sanding is done in a circular motion with a medium sandpaper until the substrate is reached. The crater created is then polished with fine sandpaper ( 400-600 grit) sandpaper and mineral oil to make the layers more visible. The layers are then examined under magnification with a hand. Substantial intial information maybe determined in this manner. This method is best when used in conjunction microscopy. Please note the numbered layers. Number 1 is the wood substrate and number 10 is the current finish. Number 3 is interesting as it is a colored varnish used frequently in the 30's and later to make painted wood appear stained.
