I just finished an shower pan for the back corner of the Globetrotter and thought I would share what I learned.
I took a paper template of the curved wall and determined the best place for the drain. I made the plug mould from styrofoam and smoothed it with drywall compound. I decided to make a simple one-time mould and put more of my effort into the finished pan than the mould.
I covered the plug with poly and laid up the fiberglass using polyester resin. First mistake! The heat from the resin curing melted the mould causing the glass to sag in a number of places. This seems to be a new problem...many sources said this method should work fine as long as the poly doesn't leak solvent. It didn't, but the stryo still melted. I'm wondering if this is a new 'green' formula styro??? Who knows.
If I was doing it again I'd pay the extra money for epoxy resin to avoid the problem and save a bunch of finishing time.
The pan came off the plug OK . I added the front lip and sanded and bondo-ed to get a smooth surface.
Once I had a surface I was happy with, I applied two coats of white Gelcoat and sanded up to 600 grit. I didn't polish the finish so it wouldn't be too slippery.
The final result ...