nothermark wrote:
On Fri, 02 Jan 2009 22:14:36 -0500, Pete Keillor
wrote:

On 2 Jan 2009 20:54:02 -0600, nothermark wrote:

On Fri, 02 Jan 2009 01:59:20 GMT, Dan@ (Pirateer guy) wrote:

On Thu, 01 Jan 2009 21:49:40 +0000, IanM
wrote:

My news wrote:
Any comment if Epoxy over Polyester will work?

No problem if the polyester is *well* cured. Months or years not weeks.
Abrade surface thoroughly first.

Also make sure you de-wax the surface before sanding.
Ummm what wax?
Polyester uses a free radical cure with the reactive diluent styrene.
Oxygen activates the inhibitor, so a wax is incorporated into the
resin-styrene solution. The wax migrates to the surface during cure
to prevent oxygen exposure and allow complete cure. Otherwise, the
stuff won't cure on the surface. You need to remove this residual wax
as it'll prevent adhesion of the epoxy.

Pete Keillor

But won't sanding take care of that?

Not necessarily. If you're not removing a lot of material, you'll end up
sanding the wax INTO the surface, where it can cause adhesion problems.
The best bet is to remove it with a solvent before you do any sanding.
That eliminates any chance of contaminating the surface.