quick little experiment

General Discussion
1

This was enlightening. I do ding repairs on epoxy and polyester lifeguard rescue boards. A friend gave me a scrap of 282 plain weave carbon fiber to play with. So I decided to laminate it with a few different kinds of resin I have on hand, and compare it to fiberglass. The carbon is 5.8 ounce per square yard, which seemed approximately as thick as some 10 ounce per square yard plain weave fiberglass I have on hand.

http://www.vma.cape.com/~patrick/temp/resin_test/samples.jpg

http://www.vma.cape.com/~patrick/temp/resin_test/resins.jpg

I used some 2 year old West System 205 hardener I had sitting around, which is partly why the epoxy came out so dark.

There’s really no comparison when it comes to physical properties. I can take the epoxy laminated samples and roll them up into little cylinders, they don’t make any sound, and they pop right back. With both the vinylester and polyester laminated samples, flexing them more than a tiny little bit causes all sorts of cracking sounds as the resin fails. I also broke off a little corner of each sample to get a feel for how far I could bend each before it let go.

This also really drove in the extent of shrinkage/loss seen with vinylester and polyester as the styrene goes away. The epoxy laminated samples came out fine. I pulled the same amount of resin off the vinylester and polyester samples with the squeegee, but as it cured and shrank, I got little dry spots in the fabric.

I just laminated them onto a piece of waxed glass. Instant shiny side!

http://www.vma.cape.com/~patrick/temp/resin_test/epoxy_carbon_bottom.jpg

http://www.vma.cape.com/~patrick/temp/resin_test/epoxy_carbon_top.jpg

Resinresearch.net was down last time I checked. Updating the site, or…?

Patrick

2

Hey Patrick,

Was there any conclusion you came to?

Was this your first time working w/ carbon?

3

Yeah, this is the first time I’ve used carbon fiber. Part of the experiment was laminating 'glass and carbon, so I could compare them. And I figured while I was at it, I’d try vinylester and polyester with carbon, even though I’d read it didn’t work out so well.

When I started doing ding repairs a few years ago, it was on an epoxy paddleboard. Then I did a few more epoxy boards, and working with epoxy was all I knew. I didn’t come at this with any custom surfboard manufacturing history baggage. I was just a lifeguard who liked paddling, my favorite board got whacked, and the guy who did ding repairs for the town was a hack. I figured I could screw it up at least as good as he was doing, so I highjacked the board one day, sent an e-mail to Force Field in Australia, asked what materials I should use to repair it, and they gave me a quick rundown of EPS polyester melty melty no no. I read Doc’s ding repair pages a few times, and had at it with West System 105/205 (not yet being clueful enough to go with 105/207). I spent three weeks doing repairs, taking them off, doing them again, taking them off… until I was happy with how the board looked. My boss saw the board when I brought it back and was like, hey, nice job. We have a whole slew of dinged up boards to fix. They’re all yours. So I tackled all the epoxy boards first, then I went to fix a polyester board and was like, wow, these polyester boards are junk! They’re fragile and soft and heavy and what the heck! Why do people even build boards with this stuff? :slight_smile:

I just wanted to play around with carbon to get a feel for it and compare it to fiberglass, because I was given a really nice epoxy paddleboard to fix this winter, and I wanted to use carbon to reinforce it along a couple areas. So before actually putting resin and fabric on this expensive board, I figured it might be a good idea to make up some little test panels first.

Having a single layer of fabric laminated that I can take and bend this way and that just really demonstrates how superior epoxy is as a matrix. As far as I’m concerned, the only downsides to epoxy are sensitization to the hardener, lack of UV resistance, and price. I didn’t really come to any conclusions that I hadn’t come to the first time I went from using epoxy to using polyester.

Most of the epoxy boards I work on are painted, so I haven’t had to worry about UV resistance. That first epoxy board I did was a hand layup clear board that was built in 1996 or so. Whatever resin Force Field used was still clear at the end of last summer. The spots I repaired with West System 105/205 are all brown now, even though they’re structurally sound. And now that I have another unpainted epoxy board to fix, I’m really interested in what Greg Loehr’s been up to. :slight_smile:

I was all set to order some SB-112, but the Swaylock’s archives are mighty persuasive toward Resin Research…

Here are the links that I botched the first time. :slight_smile:

samples

resins

carbon top

carbon bottom

Patrick

4

bravo bravo cept wouldn’t the carbon fiber heat up easily cuz carbon conducts heat well and that it is black causing the boar to delaminate?

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