Composites 101: Carbon Fiber, Fiberglass, etc.

Discussion in 'Some Assembly Required' started by HickOnACrick, Jul 14, 2011.

  1. Pike Bishop

    Pike Bishop Pull Down the Ponzi.

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    Have you checked the West System website? I would bet they've been all over that by now.
    #21
  2. P B G

    P B G Long timer

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    There are always internal sealers such as POR-15 products, or Eastwood products I trust pretty well with undercoatings.
    #22
  3. Flipflop

    Flipflop Adventurer

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    There are no resin systems, or coatings for fiberglass fuel tanks that withstand ethanol fuel at this time. Unless you have a fiberglass shell over a polyethylene tank, or metal tank it really just doesn't work when ethanol is in the mix. There are a lot of coatings that work well on metal tanks, to fill seams and rust... but the solvent (ethanol) breaks through and saturates them too, But the surrounding tank doesn't get broken down like it does with a resin based tank.

    First off... try not to buy this stuff at retail at the hardware store, or west marine. The markup between a 1 gallon pail at retail, and a drum quantity at a boat building price, you can almost use epoxy for everything... So, find a boat builder near by or look at RAKA, E-bond, and some of the other brands other than West. For polyester look at Ebay, and call around for 5 gallon pails... Should be well under $100 for a 5iver.

    The same thing holds true for air rollers, scissors, and paint brushes. (Check bodi.com for the tools. Paint brushes are 18 cents each if you buy a 24 count box...)

    PVA is a pain in the butt as a mold release, as it adds texture to the mold that needs to be sanded and buffed out. Mold release wax, works quite well. Honey Wax is what I use, but there are better products.

    Duratec makes surfacing primer that are polyester based that builds up quickly, and fills lows. 15-30 mils at one go, use a mil gauge. Go from an 80 grit finish to 800 grit wet sanding paper blocking out the eggshell, then take it to 1000, use a power buffer and buff it to a shine. I like Aquabuff 2000 on a power buffer.

    Bondo is not very good for feathering out, the grain size is huge which means it needs to be top coated with other puttys to fill the texture. I do like bondo for rough work, as I don't feel bad about cutting it with catalyzed polyester resin, so that you have a slurry you can paint over open grained and loose structured stuff like drywall mud. (Easy to sand... and cheap!)

    Evercoat Rage, or Dynalite pull much smoother without getting into expensive stuff. You might try a finishing coat of 3m Pirannha putty, followed by Evercoat Ultrasmooth putty pulled with a razor blade into pin holes and small scratches.

    Sand the plug out with as long of a sanding board as you can use, Use a spray guide coat to find your highs and lows.
    If you want to use your west systems to coat the plug, you can greatly speed up the process by using their G5 5 minute epoxy, and the 105/205 system. If you mix the 105/205, and the G5 in their own containers and then mix both together, you can make a thinner consistency product that kicks off a lot faster. A paint brush works to apply, but a squeedgee works nicely to push it into the lows. West system 407 or 410 (Or scotch light microballoons by 3m if you do a lot...) works well in place of polyester filling puttys.

    For curves, battens of clean straight grained wood or aluminum bar stock work nicely. Take chalk, pencil, ink... paint... whatever and rub it on the batten, then rub it on the curve. All the highs will show, all the lows will still be clean. Then use the longest battens, straight edges, and sheet rock trowels to pull the putty between them.

    Sand with long flexible boards, and on small stuff a paint stirrer wrapped in sandpaper. A body shop supply house can get you the 3m lineup. The red sticky backed inline paper is good for home made boards. 30 inches is about as long as one person can easily apply even pressure to...

    Zach
    #23
  4. TheOtherBart

    TheOtherBart Long timer

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    This is all such awesome information, thanks everybody for contributing.

    I've been thinking about laying up a flattrack-style seat for my XR, but I'm too buried in projects to take the time for the whole plug-mold-part thing. Can I get a decent 20-footer by laying the seat right over a foam core? For a seat like that which is going to have some compound curves should I try to use cloth or is mat okay? It seems like mat would be easier to conform to the shape. Then smooth the outside with Bondo, sand, and paint?
    #24
  5. Sir Not Appearing

    Sir Not Appearing That's no ordinary rabbit

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    I think for a "one-off" seat, the lost foam method would be a good way to go.

    I forgot one of the steps we used when I typed my original post the other night. From my research when I was developing my project above, there was some debate on whether the following technique could cause issues down the road or not. What I had read about online on some forums was the use of 3M #77 spray adhesive when using the lost foam method. So we tried it and had our best success on the vehicles that used it and had some delamination issues between layers on those that were built without it. Here is what we did:<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>

    <o:p></o:p>
    • Build foam mold by cutting, sanding, etc.<o:p></o:p>
    • Tape the foam mold on all but one side (in our case the bottom)<o:p></o:p>
    • Cut the fiberglass cloth to the size needed<o:p></o:p>
    • Spray the taped sides with 3M #77<o:p></o:p>
    • Lay the cloth on and use squeegee/bondo spreader to get it tight<o:p></o:p>
    • Mix resin and then brush it on<o:p></o:p>
    • Cure<o:p></o:p>
    • Sand first layer <o:p></o:p>
    • Spray with 3M #77<o:p></o:p>
    • Lay cloth, add resin and repeat until you have the number of layers you want<o:p></o:p>
    <o:p></o:p>
    I got the idea from R/C sites and this is how some hobbyists do R/C boat hulls and fuselages for planes that have lots of curves. After the last layer was cured and sanded, we applied a very thin &#8220;skim coat&#8221; of body filler, sanded smooth, sprayed with high-build primer, sanded, painted and clear-coated. <o:p></o:p>
    <o:p></o:p>
    I&#8217;m not saying this is the &#8220;proper&#8221; way, but it worked very well for us and the spray adhesive held the fiberglass to the curves. About half the kids in my 2 classes produced some very nice, slick looking car/truck bodies. If they had been bike parts, they would have been just fine for a 20-footer or better. Also, when we were done racing, about half the students (mostly the not-so-pretty projects) wanted to &#8220;crash test&#8221; their project so we fired them off at 40-50mph into a curb. Only one had fiberglass damage and they were all disappointed as they expected them to go out in a big cloud of fiberglass dust. Not so&#8230;. After 3 layers, they were much stronger than even I expected.<o:p></o:p>
    #25
  6. tmotten

    tmotten Lefthand ride Dutchy

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    Loving this thread. Excellent info.

    When do people tend to put a skin of fireglass over a plug to reinforce it?

    Also, when making a mould is it the exact extent of the plug at the edges, or a little extra (inch or so) to allow for it to be cut?
    #26
  7. HickOnACrick

    HickOnACrick Groovinator

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    I add the fiberglass when the last coat is tacky.

    My molds extend beyond the edge of the plug by 3-4 inches. I do this as it makes vacuum bagging easier later
    #27
  8. HickOnACrick

    HickOnACrick Groovinator

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    Flipflop,

    This is some great information. I was wondering if you can relate any experience you have with the Raka epoxies versus the West System. Raka makes a claim that their epoxies have less cratering and pinpoints when cured, as a result of additives to the epoxies. Do you have any experience with this?

    Also, you have given some great information about finishing by using different sanding methods. Do you have links to video to demonstrate these methods?

    Thanks again for your great input.
    #28
  9. darenative

    darenative Been here awhile

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    You might want to check out Silvertip epoxy. It is a lower viscosity epoxy and ends up with less surface imperfections and no amine blush. The downside is $$$
    #29
  10. Pike Bishop

    Pike Bishop Pull Down the Ponzi.

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    FWIW, I've used both and find them fairly similar. Raka's cheaper. West has better R&D (and I would say is more consistent).
    #30
  11. trackhead

    trackhead Utard Wankster

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    Good stuff Hick.

    I too have taken a liking to composites. My latest project is a fiberglass camper on my Samurai. It's a ridiculous amount of work, but it's coming along.........slowly.
    [​IMG]

    [​IMG]
    #31
  12. ebrabaek

    ebrabaek Long timer

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    I use this stuff..... Good enough to make the entire tank .....without sealing.....

    http://cgi.ebay.com/GASOLINE-RESIST...956?pt=LH_DefaultDomain_0&hash=item483a8b15ec

    :thumb:thumb
    Erling
    #32
  13. rygroh

    rygroh Noobs UNITE

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    #33
  14. Iaone

    Iaone And there I was!

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    Trackhead, I like the camper setup! I thought of making something simular for the back of a mini van. Very good info given out here. That is what I like most about this site.:clap
    #34
  15. flemsmith

    flemsmith lurk

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    I have an old set of Enduro sidebags, they're plastic, with gloss black finish.....One of them has a pretty good sized hole on the inside corner that I need to patch. I was thinking of just using fiberglass matt with resin both inside and outside the hole. Last time I tried to use fiberglass on a different project, it dried too quickly, and was so rough I could hardly even sand it....Probably a bit too elementary for this thread, but I thought I'd ask anyway.

    roy
    #35
  16. HickOnACrick

    HickOnACrick Groovinator

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    The simplest, least expensive, way I can think of doing this would be:
    Clean the plastic with acetone (or nail polish remover if that is more handy).
    Sand both side of the plastic with 60-grit so it will hold the resin better.
    Buy fiberglass mat and some resin with hardener from your local home depot.
    Assuming the hole is about the size of a quarter, tear the fiberglass mat into pieces about the size of a bagel. If the hole is larger, make the fiberglass appropriately larger. The more frayed the edges of the mat, the easier it is to apply resin later.
    Since the hole is on the inside corner, I would try taping aluminum foil to the outside. Tape the aluminum foil tight across the hole - the idea here is that as you apply resin from the inside, the aluminum foil creates a temporary barrier to prevent excess seepage, and also a mold. Waxing the side of the foil that will be in contact with the resin will make it much easier to remove later. 2 to 3 coats of auto wax should suffice. Another thing you could use as a barrier is modeler's clay - I recommend Plasticine. For a project this small, you can get enough from your local hobby shop for a couple of bucks. The more I think on it, the more I think Plasticine is the way to go on this project.
    Mix up a small amount of resin and hardener (most polyester resins and MEKP use a ratio of 1 part resin to .008 parts hardener - for 100 mL resin, you add 0.8 mL of hardener). In the heat of the summer, I would only mix up about 100 mL (3.33 oz) at a time. I can't imagine that you would need more than 200-300 mL for this project. It's a good idea to have the resin pre-measured in 50 - 100 mL aliquots prior to starting. If you can have both the resin and MEKP pre-measured, but not mixed, even better. The "pot-life" of the resin/MEKP is amount of time the resin stays liquid after adding MEKP. In Arizona, in a garage without air-conditioning, you may only have 2-5 minutes of pot life before your resin begins to gel, and you need to mix more resin.
    Plastic forks/spoons/knives can be used to mix the resin and MEKP, then thrown away.
    Remember to be in a well ventilated area, or use a respirator.
    Use Latex or Nitrile gloves that are a size larger than you would normally wear. Put on 2 to 3 pairs atop each other.
    Using a disposable paint brush (don't use those foam brushes), dab on a layer of resin onto the plastic. It will likely "fisheye" - meaning it won't remain a uniform thickness, and will have round/oval areas that look like they have no resin whatsoever. Don't worry about this.
    Put on your first layer of FG mat, use the paint brush to dab on more resin - use the paintbrush to push the resin into the mat. Repeat this process for 4-5 layers. As you are doing the layering, the resin and FG will start sticking to your gloves. When your hand starts to look like a cactus, just remove the outermost glove and you have a clean slate again.
    Allow the resin to dry to a tack, then remove the barrier (aluminum or modeling clay) on the outside of the pannier, and repeat the layering process on the outside of the pannier. If you use Plasticine, you should expect that the heat of the resin/MEKP reaction will make the clay softer and gooier. Be prepared with a set of tweezers to dig out residual clay that settles into depressions.
    Allow 2-3 days to fully cure, then sand down to smoothness. A rattle can of gloss black, plastic-adherent, spray paint should be enough to make it look acceptable.
    Finally, please post a write-up and pictures of your experience.
    #36
  17. HickOnACrick

    HickOnACrick Groovinator

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    Hey Crackatrackus, how about some pictures of your KTM panniers? Even better, why not post a write-up on how you made them?
    #37
  18. flemsmith

    flemsmith lurk

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    .....That's some great sounding advice on my saddlebags....since I'm in the middle of rewiring the bike now, I suspect it'll be sometime this winter before I tackle that. Meanwhile I'm printing out your advice for safekeeping....I might even be able to do this!

    roy
    #38
  19. troidus

    troidus Long timer

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    If the plastic saddlebags are ABS plastic, you should be able to repair the hole with an ABS repair kit.
    #39
  20. twodollardoug

    twodollardoug the calimesa kid

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    hey can i play too. i am a first time "compositeer". is that a word?:huh. i just went out and bought some of my materials today. i am using polymerproducts epoxy/resin. i just went to there facility today and got a grand tour from the owner/chemist. he was a super cool dude. i spent about 2 hours with him. that man is CRAZY about resin. i was impressed with the lab. their facility is in an unmarked building in the middle of the industrial side of town. about twenty minutes from my house. huge place.....with about half of the building dedicated to the lab and r&d. they have been there for 19 years he said.

    anyways...... i am an inmate here and mostly hang out in the orange crush. but i think my first try at this will be a car part. so i totally understand if you guys dont want to here about it. to me parts is parts......the part i have chosen is a pretty simple shape.... thats why i chose it rather than an mc part. but i wonder if i should just lurk for awhile since i really have no idea what im doing. seems like you guys have a lot of experience ant i dont want to clutter the thread.

    really just wanted to introduce myself and let you guys know im stoked on this new frontier for me.:freaky
    #40