Resin for carbon fiber

[Tiago_Campagnolo]

I have a question about the kinds of resin for carbon fiber. We have parts with carbon fiber, like the cockpit and we used epoxy resin but over the time, the resin stayed yellow. We thought in polyester resin to use just on surface because the car will stay with part of paint red and other on carbon surface. I wanted know if somebody used the polyester resin and if stayed yellow or not. If somebody have some kind better of resin to indicate I really appreciate.
Thanks

[Tiago_Campagnolo]

I have a question about the kinds of resin for carbon fiber. We have parts with carbon fiber, like the cockpit and we used epoxy resin but over the time, the resin stayed yellow. We thought in polyester resin to use just on surface because the car will stay with part of paint red and other on carbon surface. I wanted know if somebody used the polyester resin and if stayed yellow or not. If somebody have some kind better of resin to indicate I really appreciate.
Thanks

[Essayee]

I can't comment on polyester resin because we've never really used it. What I have heard of it is that it's significantly cheaper, significantly weaker for structural purposes, about twice heavier than epoxy resin, and it smells horrible to boot. Who knows though, that might just be hearsay and I would hate to propagate superstitions throughout the forums. The best advice I could give you would be to try it out yourself. I have never really noticed an issue with our epoxy resin. I guess you could say it stays yellow on our fiberglass, but I can't really tell on our carbon.

If you're interested in what our team is using, take a look at the 3:1 Thin resin at: http://uscomposites.com/epoxy.html

[Matthew Bell]

We use the US Composites 700 Vinyl Ester Resin for our body parts and other carbon fiber pieces of the car. It mixes up a little on the purple side but it produces an almost mirror like shine when cured. Provided of course that you properly prepare the molds and vacuum bag the part. The draw back is mainly the fumes it puts off. We do our lay-up outside as a result and put ventilation fans in the room where the part cures.

One important note: This stuff EATS through styrofoam, so you can't use it to make a mold. We use the 3:1 Epoxy system from US composites to make the mold over the styrofoam pattern and then coat it with gelcoat primer and sand it smooth, then lay-up the carbon fiber part after the gel coat cures. I "forgot" about this one day and mixed a pint of the stuff up in the only cup I could find, a Chick-fil-a styrfoam cup. Walked out of the room to get some gloves and came back to a nice puzzle of liquified styrofoam and resin on the table.

[benny41]

I think its probably best to speak to the company from which you get your resin from. They should be able to point you in the right direction. I think most msds also have what colour the resin dries.

We use 2 different resins for our chassis. One is a high temp resin, which leaves a slight yellow tinge, or a low temp resin that dries clear.

[Lorenzo Pessa]

epoxy resin is the best you can use.

if you want to try to mitigate the yellow colour, some black colouring can be added to resin.

[Rotary Sprocket]

The best thing to do is talk to your resin supplier. They will be able to recommend a resin and what type of kicker to use as well, as different combinations will give you different properties. I would stay away from polyester resins too. They are not good for structural applications and when they dry they tend to have a waxy surface.

[Tiago_Campagnolo]

thanks guys