The theory is that the acetone displaces the water and then rapidly evaporates, leaving the area dry and clean. What Don Casey is describing is using the acetone to dry the area after reaming out the wet core via the "drill and fill" method. Mr. Casey's book aside, this job abides no short cuts. If it's a small area, by all means use acetone before injecting thickened epoxy - but you HAVE to remove all of the wet core first and acetone won't do that by itself. Tenting a heat lamp can also work.
If it's a larger area, remove the skin, recore and reglass.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.