: I think this is what it is called. I built a Night Heron 4-5 years ago and I
: was very happy with the finished surface. I just finished fixing a crack
: in my deck (between the cockpit and rear hatch). I glassed and epoxied
: like I did when I built it but for some reason the fiber glass (a 3"
: x 10" piece I cut from a larger piece) has shown through the epoxy. I
: have completely filled in the glass with epoxy (4-5 coats) but still
: lightly see the hatching of the glass. Does anyone know why this occurred
: and how I can avoid it in the future?

Print through of fiberglass cloth usually happens over time, as the laminate is subjected to cycles of hot and cold the glass weave creates a texture on the surface which was sanded smooth. This is not visual but textural. After this happens it can be removed by sanding with 220 and then varnish. Usually the print through does not show up again.

It sounds like you have an incomplete wet-out of the glass which results in a visually detectable weave pattern. To make the glass truly transparent you must use thin resin with a slow hardener and hot temperatures as I suggest on my " Transparent Lay-up" page.

Warm temperatures keep the resin as thin as possible and the resin will remain thin when it contacts the warm boat and glass, so the resin will achieve the best wet-out of the glass fibers. Think of it. You are asking the resin to displace all the air on and around each glass fiber. The slow hardener will give the resin the time it needs to dissipate the air to the surface so your glass will be invisible.

When you're glassing exterior seams or adding a patch it's easy skip the steps needed to make the glass totally transparent, but I've found this is the only method I know of that works consistently.

All the best,
Rob Macks
Laughing Loon CC&K