Hi m8
The most common mistake when painting fibreglass is the lack of cleaning it first. People see bright and shiny clean and think itÂ’s ok to paint, leaving the recipient (you) to sort out the mess later. Not only should fibreglass be washed in warm soapy water but also then sanded with 800 grade wet and dry to roughen the surface. Saying roughen, 800 grade leaves no visible scratches, just dulls the surface, but gives the paint something to key to.
However in your case the best way to remove the paint is to use 600 grade wet and dry sandpaper and take the old paint off, then sand with 800 grade prior to painting. However on something as shaped as a Vader mask this is going to take a while so persevere and be patient. Then pending where you live to who sells it, but you can by plastic primer from most car shops which works well, or if you have assess to an airbrush or spray equipment you can buy proper 2k fibreglass etch primer, which is best. Give it a couple of coats then sand with 800 wet and dry to smooth off, then give it another 2 coats and sand with 1200 or 2000 grade wet and dry. Then give a couple of coats of matt black paint then sand again with 2000 paper, then give it another couple of coats then sand again with 2000 paper. Then give it a couple of coats of clear lacquer, sanding between coats. By using matt black and clear lacquer over the top give the paint a real depth to it.
Another thing it might have been is whoever made it used flowcoat gelcoat which is normal gelcoat mixed with wax solution so it cures in the air. Normal gelcoat only cures properly if painted onto the surface of a mould so itÂ’s void of air. Hence the inside of the mould stays tacky so the matting can be applied. If it is flowcoat it will need keying with 320 grade paper then spraying with high build primer to smooth off the scratches. The wax solution is impregnated into the gelcoat so no amount of washing will remove it.
It might be the flowcoat option, if it was made from a silicon mould, as gelcoat doesnÂ’t set to well against most siliconÂ’s, but using flowcoat instead of normal gelcoat overcomes the setting problem. However if this is done, the flowcoat should be pre coloured to save painting.
Sorry its not a more cheery reply.
Don
ps if you can post a picture of it so i can see where its flaking from
