ive been doing lots of overlays onto wood with great success,i was asked to do the same part but one that came in plastic,its a dash insert,5 parts,4 have worked but the main long one doesnt seem to be bonding very well.as usual i sanded all old paint off and scuffed with 40 grit,acetone clean and then brushed black tinted silmar surfboard resin on,let it tack,added carbon,dry,4 layers of silmar and then a final layer of wax in silar,no problems there,perfect overlay but if i twist the part i can see/hear the overlay cracking away from the part.
im guessing i can fairly easily fix this by brushing epoxy in the gap,its not a gap at the mo but could easily be lol!
i also have another identical part to do and want to avoid this again,im guessing i can use a black tinted epoxy as my first tac coat instead of the poly,then add the carbon and continue to add the silmar as before?? working on the basis that epoxy sticks to th eplastic(which i know it does)
cheers
heres a finished set,the problem area is on the long part on the 2 edges that go along the long vent hole.
