Not meaning to differ from anything Brian has had to say, I'll add my 2 pence about gel coat.
This is from knowledge gained from years of working on boats, then digging into the Lotus.
Gel coat is just polyester resin (like used in typical fibreglass layups), but optimized to be an exposed surface layer.
- It's optimized for color
- It is resistant to UV degradation
- It can be polished to a high gloss
There's none of that on my 1972 TC. And no need, as it's going to be painted.
When making the body, first step is to spray resin into the mold. Then a 'chopper gun' is used to deposit glass strands for reinforcement. Then more resin is sprayed to encapsulate the glass and complete the layup.
Pretty simple. And in the case of the Lotus bodies, too much resin is used relative the the glass reinforcement, resulting in lots of opportunities for stress cracks to form.
Anyway, don't concern yourself with gel coat, as you don't have any. When you sand through the paint, the next thing you see is the thin layer of resin that was deposited on the female mold before applying the glass strands.
-Vince
