NGA Gelcoat over epoxy lamination

[ducaes]

hi there guys..

this is my very first post after i signup a month ago..i'm from malaysia,and work for a yachtbuilder..we build powerboat ranging from 42 ft upto 72 ft..anyway,there this problem which i hope you all could enlighten me to..there this door,that we build for our 61ft sportfisher out of bi-axial mat and epoxy resin,which finished of with Reichold NGA Gelcoat..problem is after the boat delivered to the owner,3 months after that,the gelcoat seems to delaminate,i mean peeled of from the lamination..what could be the reason,we did ask around and it seems that polyester and epoxy resin doesn't bond that well,you need a sort of primer to strengthen the bonding..so i hope anyone out there is kind enough to shed some light into this problem of mine..please refer to attached picture below which show the damage done..thanks!

[Herman]

Basicly:

polyester gelcoat over epoxy = no go.

The other way round might work, but we always recommend to put a VE resin with mat behind the gelcoat, sand that, then apply the epoxy laminate.

[ducaes]

thanks herman...cheers!