spar varnish

[pauld3]

stupid question, do you sand the epoxy before you apply spar varnish, and if you do what grit and do you sand between coats of the varnish.
thanks paul

[doug hodder]

Paul, yes you need to sand the epoxy before you apply any top coat. It has to have a "tooth" to bind to. I sand it with 220 prior to shooting or applying any top coat. 220 scratches can be hidden with top coat, and don't forget to wipe it down with a degreaser prior to top coating, denatured alcohol will work if you don't have the official stuff. Remember, the smoother your sub surfaces are, the smoother the final coat will be. As far as between coats on the top coat. I'd read what the manufacturer recommends. Doug

[Juneaudave]

Couple other thoughts...

Epoxy cures quickly to a sandable solid, but it can take as much as a couple weeks at room temps to be fully cured. I always suggest you wait to sand until you are comfortable that it is fully cured due to toxicity.

Epoxy sanding dust is the nastiest!!! It gets everywhere and is really fine. If you sand inside, be sure to clean up good and cover your benches and stuff prior to starting...otherwise you'll be living with that dust for a good while. Really annoying!!!

Wear a mask or respirator...be sure to keep yourself covered and wash up after a sanding session to get that dust off your skin!!!

For spar prep, 120 grit on a random orbital sander is fine (IMHO). If you are using a clear coat (and I've never used clear like Doug), I'm a guessing that the 220 grit is probably preferable.

If you are using glass, be very carefull to have enough epoxy build up so that you don't sand into the glass itself. Once you cut the glass with a sander, it will always show in the sunlight no matter what your finish coat is...Juneaudave

[Wimperdink]

I learned from sanding fiberglass and or epoxy that its a dirty job. Here's what I did when I was building one of my pirogues to take a huge amount of the nasty out of it.

I purchased the bag to go inside of my mini shop vac and plugged it directly into the filter side of my RO sander. It cut down the dust by about 85%