Polyester resin

[Vumad]

I did a search and didn't find the answer to my question.

I understand that Epoxy resin is easier to work with, and I've heard that it's better. I've worked with epoxy and small amounts of fiberglass for repairs.

My question is about polyester resin. I have read the stuff on US composites. I'm not afraid to work with glass and epoxy, buy can anyone give me feedback on poly resin? Is it much different that epoxy? Will it be strong enough? Is it much harder to work with? Etc... feel free to elaborate. I can read on manufactures web site all day but it's not going to give me the real deal info.

I would of course prefer epoxy, but Poly Resin is just so much cheaper. Cloth is super cheap, just that epoxy can be pricy. At nearly half the price, that poly resin would give me a lot more buying power, which is good because I have so little buying power. :doh:

 

[suva]

Polyester resin won't properly adhere to most hulls (learned that the hard way) epoxy resin will.

 

[Ottis]

Polyester resin won't properly adhere to most hulls (learned that the hard way) epoxy resin will.

True, use epoxy on smc hulls

 

[Vumad]

I don't know what SMC is. My hull is stock. See, this is why I asked. UScomposites said Poly resin is becomming popular for marine applications and the stuff wouldn't have even worked???

 

[Mouthfulloflake]

poly will only stick to poly.

epoxy will stick to anything.

so, you cant use poly over epoxy, but you CAn use epoxy of poly.

 

[brentR]

You positive you cant use Poly over top Epoxy?

 

[eel]

poly will only stick to poly.

epoxy will stick to anything.

so, you cant use poly over epoxy, but you CAn use epoxy of poly.

mouthfullofflake is telling the blatant truth.

Vynilesters (sp?)are a bit different but why be a pioneer on a repair?

 

[keefer]

I don't know what SMC is. My hull is stock. See, this is why I asked. UScomposites said Poly resin is becomming popular for marine applications and the stuff wouldn't have even worked???

SMC is Sheet Molded Compound. The SJ bottom deck on all years is SMC, the top deck on the 96+ SJ is polyester.

 

[QJS]

Really the price says it all. Epoxy is by far the strongest, then Vinylester, then polyester. Remember that if you use chopped strand mat epoxy will not melt the binders like esters do. Nice to see some people using Vinylesters in their hulls now (WCF) it is far superior to polyester.
Chris.

 

[ketsair]

fyi, the reason poly doesn't work well with SMC is that smc has release agent pressed throughout when it's formed, when you grin to get a clean surface, you reveal fresh release agent in the glass, but that release agent evidently has no effect on epoxy resin

 

[Vumad]

Then the poly resin should be just fine for anything above the bond line? And I'd need epoxy below the bond line for reenforcement? Really, I'm just looking to work with the tray and the hood.

 

[Vumad]

So that stuff at walmart is poly resin then. I don't think I like that set up, I'll probably just go with the epoxy. 50/50 mix is easier, plus I know how to use it, and it's better... looks like it's going to be worth the extra $$.

Maybe someday if I start fabing w/ glass, I'll use poly.

 

[waterfreak]

polyester resin is only good for laying up parts. Of course it is cheaper and easier to work with but , just like everybody said, do not use it to re-inforce or fix anything that involves SMC. Only use epoxy

2:1 is best for lamination applications

 

[WaveDemon]

Then the poly resin should be just fine for anything above the bond line? And I'd need epoxy below the bond line for reenforcement? Really, I'm just looking to work with the tray and the hood.

that is correct for a round nose superjet. not sure on your 650sx. if you bring it to tom21's shop someone could tell you for sure by looking at it.

 

[winterstick]

I don't know what SMC is. My hull is stock. See, this is why I asked. UScomposites said Poly resin is becomming popular for marine applications and the stuff wouldn't have even worked???

it's actually the opposite, poly has been around for years and epoxy is now (20 years or so) making inroads into the marine market

 

[gj_fx1]

polyester doesn't really even bond that well to regular (poly) fiberglass.
It is good if you are making a whole part (ie building a boat..) since it all cures at once. It is "ok" for cosmetic repair on fiberglass, but otherwise use epoxy regardless of what kind of hull you have.