I’ve been spending some time over the last few days dressed like this, painting liquid latex onto the polystyrene mould for the big resistor.
When you’re doing a big area like this, the ammonia can be overwhelming without breathing gear. You can see the coat of latex around the edge of the mould. Two coats are required.
Before beginning to fibreglass the big mould i’m going to do one last test with a small piece I have shaped with a similar curve. I’ll get a feel for the consistency of the epoxy mixed with the microfibre, and get some practice in application techniques. It will be necessary to glass each mould in one go to avoid colour differences between batches of epoxy. It will probably be a two person job. After about an hour, and while the epoxy-microfibre coat is still sticky, we will lay chopped fibre mat over the top to provide structural strength. With any luck you won’t be able to see the chopped fibre from the outside of the work, as the first coat of epoxy-microfibre will be diffuse and semi-opaque.