ftsoft wrote:........ Also once he sanded down to the fiberglass what SHOULD he have used to build it up again? Layer up fiberglass? Just wondering.
Large areas of damage should be ground out and reglassed with fiberglass matting. Small star cracks and crazing should be ground back sufficiently to get through the damage and then either reglassed with standard weight matting or with fine surfacing tissue if more superficial. Final surfacing can be done with a thin skim of polyester filler. Miles Wilkins recommends coating the whole shell once repaired with polyester spray filler (special filler thin enough to spray with the appropriate gun) and I have used this method and concur.
If you do a quick search you will find this has been discussed many times on the forum.
FWIW I strongly advise that water should be avoided in any stage of the preparation of a fiberglass shell until the final primer coat is flatted. In this respect my advice differs from Miles.
(Never Never flat fillers wet, they soak up water like a sponge)
Obviously if you have a spray oven suitable for use with a fiberglass shell you can take more liberties with water during prep' but most of us do not.
Be warned IMO not all the methods described are good ones, although I do not claim any great expertise