Rant and Build: NOTMYBIKE... builds a super light F650-R

Discussion in 'Thumpers' started by notmybikemodelname, Jun 22, 2010.

  1. notmybikemodelname

    notmybikemodelname KOTW is a myth!

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    That's a good story, have another one?
    It's unsprung weight and small, so weight is not that important. You need to build for impact resistance, so on a bike that will hit the dirt often forget about Carbon Fiber. You'll need a 3-3.5mm laminate due to the vibration. So I would go with pure fiberglass bi-directional with epoxy resin. It's very drapeable and wets out nicely. About 3 layers of an 18oz would be sufficient.
  2. tmotten

    tmotten Lefthand ride Dutchy

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    Cheers. Planning on making a completely new seat for it. Had a few modified by a local buy and it doesn't look that hard. Plus it was a good excuse to buy an air compressor. So far this project has gotten me a compressor, orbital sander and plasma cutter. Love collecting tools. :evil

    Plan is to make a prototype from simple glass matt and keep it as thin as possible and drill it to Swiss cheese. The rear will taper back to allow for a giant loop and will be largely empty of foam to allow for spare parts at the back inside the seat. The new sub frame is horizontal so I've got more room for that stuff now. This is my travel bike so I need space for all that crap. To stiffen it I'm thinking of using carbon tubing laminated in between the sub frame which is actually available locally for a change. Any tricks I should know about on how to laminate in tubes?

    I'm thinking that if I start with few layers and under do it I can always add more if it turns out that it's not stiff enough. That way I'll find out what minimum I can get away with. Guess I'll find out.
  3. beechum1

    beechum1 Dandole Gas al Burro

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    we used to use two layers of 7oz plain on our parts with an epoxy resin. 5 years later the parts were still flexible and didn't crack or splinter when twisted. Be sure to get out all the resin not needed for complete wetout.
  4. tmotten

    tmotten Lefthand ride Dutchy

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    May sounds a bit ignorent now, but how do you work out how thick the laminate will be with layers sold in ounces/ yard?
  5. notmybikemodelname

    notmybikemodelname KOTW is a myth!

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    That's a good story, have another one?
    It's in the MSDS sheet (spec sheet) for the material.
  6. tmotten

    tmotten Lefthand ride Dutchy

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    The spec sheets on the Fibreglast site only refer to nominal thickness, but it's very thin (0.3mm) and wouldn't include the resin. Is there a rule of thumb or something?
  7. notmybikemodelname

    notmybikemodelname KOTW is a myth!

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    That's a good story, have another one?
    Hand laying will result in a 25-30% increase in thickness per layer.
  8. dakarchef

    dakarchef Been here awhile

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    Went to the composites shop today... They had no bi in that weight. But I walked out with an end cut of 9 oz s glass for 20 bucks. Looks like that's what I'll do it with.
  9. tmotten

    tmotten Lefthand ride Dutchy

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    What layup are you going to use with that?
  10. dakarchef

    dakarchef Been here awhile

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    I should have clarified ... The end cut was about 4 yards. I'm planning on doing my one piece low front fender with it. Just have to figure out # of layers. They guy in the shop recomended 3 layer, but that is only the equiv. Of 27 oz. Glass. His words were, "it is strong as hell ". Hopefully tomorrow I can get the mold cleaned up and ready to do the first fender.
  11. tmotten

    tmotten Lefthand ride Dutchy

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    That's what I keep getting told by all these boat guys as well.
  12. notmybikemodelname

    notmybikemodelname KOTW is a myth!

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    That's a good story, have another one?
    If it's just "cloth", it's not that strong. Unless of course you're comparing it to tissue paper.

    "strong" is relative anyways. strong for the weight? Strong for the laminate? or Just plain strong? And then is it strong in tension, impact, compression, or do they mean "tough". And all of these are based on what resin you use and the techniques for contruction.

    General rule: Don't laminate multiple layers of "cloth" without mat between each layer. problem with mat is that it is not "sized" with the propert chemicals to allow epoxy construction. So you'd be stuck with polyester or vinylester, which neither have even half the "toughness" of epoxy.

    What to do, what to do?......................:lol3
  13. tmotten

    tmotten Lefthand ride Dutchy

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    So you're saying matt wedges between layers of weave with epoxy would work? I'm going to make a first run in glass I've decided in case the design shits me.

    Can't be bothered with that for the headlight bracket which will also be a copy of your design. I'm putting a Infinity projector in there though with the HID ballast bolted to the side of it. The weight of the HID and projector will be 0.55kg (1.2lbl). I was going to pickup 2x2 twill carbon kevlar from Fibreglast. What to you reckon the layup should be with that 5.4oz fabric. 5mm? It'll be used with masses of corrugated road. The projector mounts with 4 bolts. 2 on the top and 2 on the bottom in a square shape from the front.
  14. notmybikemodelname

    notmybikemodelname KOTW is a myth!

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    That's a good story, have another one?
    I'd say between 3 and 3.5mm if you're bolting it to the fairing. If not, in order to keep the vibration down, 5mm would be advisable. It's also best if you sandwich layers of bi-directional or cloth between each layer of twill. It promotes better bonding between layers of twill than twill on twill.
  15. tmotten

    tmotten Lefthand ride Dutchy

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    Righto. Yep, was going to use the lighting bracket also as fairing bracket.
  16. DRjoe

    DRjoe Long timer

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    There are a lot stuck in there ways mate, nothing but choppy and polyester resin in a lot of boat yards.

    I asked for a 4lt tin of vinylester resin from a well known marine ware supplier, The answer i got was "whats that"
  17. notmybikemodelname

    notmybikemodelname KOTW is a myth!

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    That's a good story, have another one?
    :lol3

    That's about right. There is actually a boat building company in Thailand that builds very expensive luxury cruising yachts that and they actually shred newspaper on site and laminate it between each layr of glass :huh
  18. tmotten

    tmotten Lefthand ride Dutchy

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    That's a great idea.............. ..:slurp
  19. tmotten

    tmotten Lefthand ride Dutchy

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    Rethinking the seat at the moment. I'd like it to go further forward by this means putting a weight load onto the airbox which really goes onto the throttle body and really onto the rubber manifold. Rob, how much weight do you ever put onto this area? And don't tell me the weight of your nuts. That little bit doesn't come into it. :deal
  20. notmybikemodelname

    notmybikemodelname KOTW is a myth!

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    That's a good story, have another one?
    I do load up the front of my seat often, but my seat doesn't come into contact with the airbox. I actually turned my throttle body boot around and mounted my throttle body backwards. Being fuel injection it works the same as stock position but is 2" lower. Then I used a K&N cone racing filter. This is how I achieved such a low profile.