We keep saying that Ester type stuff will not infact stick to epoxy based resins. But, how come west system says the following.
http://www.westsystem.com/ewmag/22/polyester.html
im sure its b/c west system themselves can say whatever they want. but has anyone ever really tried spraying a clear gel coat uv in their molds, b stage, then infuse with epoxy!? i was only wondering.
But Epoxy will stick to anything. But PER is supposally won’t stick to cure Epoxy that well…
So… gel coats can. per to epoxy can not. hmm… hmmmm…
and to add to this question.
Styrene… what is that. this will not go well with epoxy right? B/c u can use a sty. thinner in the gel coat.
I like this link. it helped me understand a lot… i didnt know that gel coats dont dry with air.
http://continuouswave.com/maintenance-logs/epoxy/
guy used pva to spray on top of the gel coat to let it dry.
But only if the gel coat is the last layer, if it is the first, you want it still tacky to place the reinforcements in.
You can also use surfacing agent (liqiud wax) in the gel coat for a full cure as sanding resin has it in it.
someone please correct me if I dont get this…
Most epoxy has a amine blush on the surface when it cures, the amine blush will not let the PER or gelcoat cure where it is in contact. You can sand off the blush (when the part is fully cured) and spray a poly product on it BUT you get no chemical bond from the part to the poly topcoat.
I did a piece to play with Duratec one time and I didn’t sand the part very well before I sprayed it. It looked good and I was happy untill I wet sanded it and as I did I noticed a white spot, it was the Duratec coming off the part, I chiped a small area and blew a air hose on it, in about 5 min I blew off all the Duratec from the part.
There is stuff like SB-112 that PE can be sprayed on but SB-112 has a short pot life, is rather thick and high $(stuff I have is anyway)
so as for me no chemical bond for poly is bad. just my $.02
well ive been reading and most people have gel coat as the first layer in a mold, then the epoxy which is infused. so the curing of both materials take place and fuse together i would think. no?
Ok, worded another way. If the PER is “B” staged or dry, Epoxy will stick to it 100% as Epoxies stick to everything!
If you have Epoxy lay down and cover it with PER, you most likely will have troubles with the coating.
booom digity. (sorry for the corny words) good to know. the part i made the other day came out great! im just no patient enough that since its a big cold, the epoxy didnt cure 100 % only 99.9%.