liquidlounge

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From this forum, I have learned that epoxy based and polyester based materials are not compatible, especially when gel coating over epoxy based materials, correct? I want to make a 10" speaker hole into an 8" speaker hole (not exactly what I'm doing, but easier to explain and analogous to what I'm doing). I want to bond a pre made fiberglass board and fill the 10" hole from behind. Because of where its located, this is about all I can do from behind. The only boards I can find are epoxy based, so I would glue with an epoxy based product, right? Now, when I go over this board with the standard vinyl/poly based resin system am I looking for trouble? Actually much of the repair is going to show in a prominent place. Am I approaching this repair all wrong? I really don't want to scarf out the fiberglass from the front because I would be getting into a gel coated logo. Any suggestions are appreciated. Thanks in advance, Dave

liquidlounge

iTrader: (1)

I just found a product called "fiberglass polyester laminate board". I assume this may be compatible?

glassdave

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I am going to assume your boat is built with poly, in that case everything is compatible, but you should use ve (vinylester) or epoxy. Heres a quick run down

you can use epoxy on poly (or ve) but not poly on epoxy (or ve)
ve you can use on poly but not on epoxy
epoxy you can use on just about any laminate

you can use gel coat over epoxy but the process is fairly precise and risky if you dont get it right.

any pics?

JRider

iTrader: (1)

If gel is poly, can it be used over VE?

glassdave

iTrader: (1)

yep

JRider

iTrader: (1)

Maybe i am confused, why cant you use polly resin over VE but you can use Gel coat? Or did i read your post wrong?

glassdave

iTrader: (1)

i really couldnt tell ya and that is something i have always wondered myself but thats what i was told early on and i never questioned it much further. If i could find a good convenient source for a VE gel i would be using it. I just switched to Comp One and am going to look into it.

You can use poly over epoxy as long as you control the amine, its just very difficult to someone that doesn't do it every day. I suspect because VE is in a styrene matrix it does not inhibit the cure in poly . . . .