I've roughed out a foam plug for some new bodywork working off cad drawings. I've used celotex type low density insulation and i'm now looking to start coating and filling. I was considering covering the foam plug in a fibreglass skin and then building up the finish in layers of polyester primer filler. Can you recommend a suitable cloth and a whether I can use a polyester resin or ?. I have made the plug approx. 3mm smaller than the finished item to allow for a finished build up. ( I attach a photo pre sanding to give an idea of curvatures. Thanks

I use a low density PU foam board (Xtratherm) to make my male plugs. I then coat the foam with two coats of Polyester resin (sanding down between coats) to produce a good, tough surface which gets fine sanded to 800 grit before it gets waxed, polishing and PVAd. I then apply a generous coat of polyester resin to act as a gelcoat layer followed by three layers of E-glass woven fiberglass to give me a very nice female mold which I then use to fabricate carbon/kevlar parts. You can see lots of photos here:

http://carbon-dragon.ihpa.ie/index.php/cd-builders/phil-lardner-s-cd#new - scroll about 2/3rds down that page to find some photos of a foam plug.

http://carbon-dragon.ihpa.ie/images/carbon-dragon/CD%20Builders/Phil%20Lardner/Photos/Carbon%20Dragon%20-%20unsorted%20photos/thumbs/20150102_004425.jpg

Phil.