learning how to work with composites

Discussion in 'Thumpers' started by jesusgatos, Mar 21, 2011.

  1. jesusgatos

    jesusgatos fishing with dynamite

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    Got a bunch more pics for you tmotten:

    Spent most of the day building-up bondo and sanding down bondo. Can see in this first pic how the lines on the bottom of the handguards are a little bit wavy.

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    Looking pretty good from above, but there were some dips that I needed to fill, and contours that I wanted to smooth-out.

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    So I used a shapie to mark-up the handguards and then slathered-on another layer of bondo.

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    Then I sanded-down the handguards, using the sharpie lines sort of like topographic lines on a map. Works pretty well, as the lines start to show through a little bit before you actually get down to them.

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    #21
  2. jesusgatos

    jesusgatos fishing with dynamite

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    Oh, and these are the tools I've been using. Nothing fancy.

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    #22
  3. jesusgatos

    jesusgatos fishing with dynamite

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    After a few more layers of bondo and a lot of sanding, I'm really starting to like how these are looking. Almost done with the basic shape.

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    #23
  4. jesusgatos

    jesusgatos fishing with dynamite

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    ...and then I did this. ugh. Was just wheeling the bike around so I could clean-up the dust, and accidentally knocked the handguard against that big green engine container you can see in the background. No big deal, but man that pissed me off.

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    #24
  5. jesusgatos

    jesusgatos fishing with dynamite

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    Next step was to put a radius on the top edge of the handguard. Wanted to roll the top edge forward so there's not a sharp edge pointed at the rider. Made a paper template and taped it to the handguard and handlebars. Then added a few layers of bondo (allowing time to dry in between layers) to build-up a an oversized radius that I'll sand down tomorrow. That's all for today.

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    #25
  6. CaptTeach

    CaptTeach Been here awhile

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    Nice work so far!

    One thing you may want to think about is using a polyester resin for your plug work - a bit cheaper and if you heat up the mix a bit it is workable in short order. You dont need as many of those barley-pops to get thru the project either.

    One other little trick If you find you have cut a piece out of mat that you think is too thick to conform to your part, you can separate it into layers and then lay it up in pieces.

    To make a thinner filler than bondo or glazing putty, add a bit of baby powder to your resin - its cheaper than buying the 'Talc' from West Systems

    Have Fun
    #26
  7. jesusgatos

    jesusgatos fishing with dynamite

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    Thanks, those are great tips about separating the mat and using baby powder to thicken the resin. Rob and I talked about using polyester resin for the plugs and molds because it''s so much cheaper, but he told me that it's more toxic with offgassing and VOC's and blahblahblah. For what I'm doing, I'm not too concerned about the expense, but it would be nice if I could speed-up the curing process a bit.
    #27
  8. jesusgatos

    jesusgatos fishing with dynamite

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    Spent a few hours shaping the top edge of the handguard. Used a die-grinder to hollow-out the basic shape and then hand-sanded it until I was happy with the shape, and I like how it's looking at this point. What do you guys think?

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    #28
  9. jesusgatos

    jesusgatos fishing with dynamite

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    Success! Waxed the mold yesterday, threw some garbage bags over the bike, and laid-up some fiberglass. Went pretty smoothly, except for the heavy mat. That shit is nasty. Just turned into a giant hairball. Didn't want to conform to the shape of the mold at all. Wrestled that one piece into place, then covered it up with a few more layers of the medium-weight cloth (decided not to use any more of that mat). Let it cure overnight and popped it out of the mold today. Have invested a ton of time in that mold, so I was a little bit nervous about this part. But it came out just fine and that was a big relief.

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    #29
  10. jesusgatos

    jesusgatos fishing with dynamite

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    Cut the part out, filed/sanded it down to the right size, and then painted the outside of it, just so I could get a better idea of what the finished handguards will look like. Drilled-out the mounting holes and bolted it onto my 650. Was a little bit concerned about the fit from one bike to the next (because of how the handguards have to be tweaked to fit the bikes, and then get wadded-up when we crash), but they fit great. Plenty of clearance for my fingers too. I wear size 10 gloves and can't imagine that I'd ever manage to touch the inside of the bottom part of the handguards. But I like knowing that it's there, and feel pretty confident that it will reduce the chances of hands/arms getting tangled-up in the handguards in a crash.

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    #30
  11. jesusgatos

    jesusgatos fishing with dynamite

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    What I've just posted pictures of it not the finished part though. It's just the plug for the inside half of the mold. The outer part of the handguard that you can see is just a rough layup. The finished parts will look much nicer. We're going to use a 3D scanner to import that part into SolidWorks, where I'm going to tweak the design a little bit more. Want to add a radius to the back edge of the lower part of the handguard, as well as some recessed contour lines, recessed mounting holes for the handguard mounting hardware, etc. Will also be able to mirror this part in SolidWorks to create an identical CAD model of the left handguard. Then we're going to use a 3D printer to make plastic parts that will be used as plugs to create the molds for these handguards. That's where my work ends and my brother Robo will take over.
    #31
  12. tileman

    tileman Long timer

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    Fantastic work and write up!!!! What sort of scanner do you use?
    #32
  13. jesusgatos

    jesusgatos fishing with dynamite

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    Thanks. Don't have our own scanner, so we have to pay to have things scanned. Rob's going to handle that up in Chico, so I'm not sure.
    #33
  14. VxZeroKnots

    VxZeroKnots Long timer

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    jesse, everything you do over here or on pirate is badass. carry on, if you ever make it to NW montana beers are on me. flipoff2:
    #34
  15. jesusgatos

    jesusgatos fishing with dynamite

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    Thanks, and Montana's on the list, right after Idaho.
    #35
  16. ebrabaek

    ebrabaek Long timer

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    Very nice indeed....... Lot`s of determination here...... Awesome.....:thumb:thumb

    Erling
    #36
  17. jesusgatos

    jesusgatos fishing with dynamite

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    Hi Erling. Am actually out in CO right now, going to be road-tripping through NM all this week. Never been there before.

    Robo-Boogie and I spent some time looking into 3D scanners and I think we're going to get one of those NextEngine scanners, but they cost about S4000, so we just sent that handguard out to be scanned. Will post some updates when I get the files back and start messing with the CAD models. Robo has been working on some other cool composite projects too...
    #37
  18. jesusgatos

    jesusgatos fishing with dynamite

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    Started working on a new project. Shaping a gas tank right now, using sheet metal to create ribs that I'll use as guidelines to maintain symmetry. Decided to try 4lb foam this time because I thought the 2lb foam I used for the hand guards was too soft.

    Hey Erling, question for you: How should I go about making a filler neck for this thing? Can cut something out of an old tank or have a new filler-neck made to install now and make the filler neck part of the mold. Or I could have an aluminum filler necks machined and try to bond those to the tank? What's the best way to do something like this? And on a related note, what about threaded inserts for the petcock and mounting points?

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    #38
  19. jesusgatos

    jesusgatos fishing with dynamite

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    #39
  20. jesusgatos

    jesusgatos fishing with dynamite

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    Was just updating my portfolio and realized I've got a few more pics to share. So here are a couple of screen-captures to show what the laser-scanned hand guards look like. Going to make a couple of small design changes/tweaks, then mirror this part to make the left-side, so we'll have two perfectly symmetrical hand guard shields. After that's all done, we'll have these molds rapid-prototyped (made out of plastic) and then we'll use those plastic parts to make aluminum molds. Shaping the first hand guard shield was pretty easy. Making a second one to match the first would have been much more time-consuming. Funny because with most of my other projects, it's usually the other way around.

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    #40