Custom/Hybrid resin

[jeremy chambon]

I am getting ready to do some fiberglass work on my sn js. i believe i have a fiberglass top deck and a smc bottom. I hear poly resin doesn't stick to smc and epoxy resin is the way to go because it adheres to fiberglass and smc. But i went to the local body supple shop and he suggested smc resin. He says its just as strong and will adhere to smc better then epoxy resin and it will adhere to fiberglass just as well as epoxy resin. has any one used this and can confirm this?

 

[Shadow7874]

Ive never heard of it but a quick google search claims its actually polyester resin.
http://www.ehow.com/facts_7673682_smc-vs-fiberglass-resin.html

I think the epoxy would adhere best but im no professional.

 

[Matt_E]

I did some quick research. Evercoat SMC resin should work.
When asked why their polyester based resin would work on SMC, here's the answer:

The reason that SMC Resin work on SMC panels where regular polyester resin won’t is because SMC resin contains a small amount of Methyl Methacrylate (MMA) that help to increase the bond. The MMA works to compensate for the mold release that is in the SMC panel. SMC stands for Sheet Molded Compound/Composite.

In order for the material to be molded it is placed inside of the mold which has a positive and negative side. The material is compressed between theses two sides during the manufacturing process. After the part is cured the positive and negative molds are separated and the part is removed. In order for these parts to come out of the mold a release agent is incorporate into the resin that allows the parts to easily removed, otherwise they would stick to the molds. It’s this release agent that causes the issue for traditional polyester resins to not stick.

 

[509freerider]

Just order a gallon of 3:1 epoxy resin from US Composites and be done with it. Your top deck is not fiberglass it is made of Metton and has too much flex to work with the SMC resin that cures very hard. The SMC resins I have used are also way more expensive and harder to work with than the epoxies, in my opinion. I think the supply shop is right in that SMC resin bonds to SMC better than epoxy, but where your working with two different materials I would just go with the epoxy. Good luck!

 

[jeremy chambon]

thxs for the help it looks like i have a return to make. im planing on cutting the front of my sn of and rounding it out / making it shorter i was told to use biaxials 1208 which is 12oz and to use 2 to 3 layers does that sound right?[SIZE=-1][SIZE=-2]
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[2010brandingo]

go epoxy . . . i have used smc resin several times on various things years ago and would not suggest it to anyone, nor will i ever use it again.

 

[GDFL]

I did a similar project a few years ago. You can see what I used and how many layers here: http://www.x-h2o.com/threads/8334-Lanier-07-Buildoff-Contender&highlight=contender

In short, I used many layers of 1708 Knytex and US Composites epoxy resin. It never cracked anywhere even with a few good tests.

I can say that it was A LOT of work and many many itchy nights. I enjoyed it, but probably wouldn't do it again.