> When repairing scratches, gouges, etc., or making modifications to a boat,
> with varnish over epoxy over glass/wood surfaces, should the old varnish
> (still clear and in good shape) in the immediate vicinity of the
> scrape/attachment point be stripped away from the area for a distance
> before laying on the new epoxy? Or is it ok to go over good varnish with
> epoxy?

> thanks for any thoughts, JR

Get rid of the varnish and sand into the epoxy a bit to roughen it so you get a good bond.

Otherwise, you'll have a layer of relatively weak varnish trapped between two layers of relatively strong epoxy. When the structure is subjected to stress and flexing, this would be the weakest spot, and it should come apart right along that joint. This is probably not what you want.

The varnish is a finish, and not a structural component. It is really just to provide UV protection for the epoxy, and fill in fine scratches left by the final sanding.

If you are working with polyester resin then varnish is not needed except to fill in scratches from sanding, and to make things look pretty. In this case you could replace it with a fewe minutes work with fine sandpaper and some wax.

Paul G. Jacobson