How much before epoxy?

[tomstock]

I'm getting to the point at which I need to glass the hull... but I don't want to oversand before this if I don't have to. Should I be filling ever crack, crevice and screw head/hole before laying down the glass? How much bondo and sanding is necessary before glassing?

Thanks

Tom

[Brent]

I recommend making sure the hull is fair and curves are smooth. The ply edges should be rounded over nicely and filled to make a smooth surface for the cloth to adhere to. Screw heads should be counter sunk and filled, but small nail or screw holes need not be filled as long as you can eventually fill them from the other side with epoxy. If you glassed the ply joints, fill and sand these until fair. Basically any place that might result in a void under the glass needs to be dealt with before the glass goes on.

[Frank Hagan]

Brent's right. The glass and epoxy hides a lot of small defects, so don't worry about the small stuff. I worried about things like a fingernail-dent sized defect, and those don't matter. You don't want to trap an air bubble under the glass though, so any larger holes should be filled.

If you use fir plywood, don't oversand either ... the softer white portions of the wood wears away first, and the harder darker portions then form a kind of washboard effect. I ended up having to use "fairing putty" to make up for a washboard hull side.

[Craig]

Good advice all. Minimize the use of bondo. In time the stuff shrinks and if you are going to have glass problems it will be in the bondoed areas. Use epoxy and microballoons for fairing.