Question Making a fender from GFK

Discussion in 'Workshop' started by faffi, Feb 21, 2018.

  1. faffi

    faffi A.S.A.N.

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    I plan to make a rear fender from glass fiber mat and resin in order to get the correct shape and size I need. At one end of the fender will be a tail light plus licence plate, similar to that of the KZ650.

    Now to the question; should I reinforce the fender with sheet metal inside, or do you reckon it will be strong enough on its own, provided enough layers, of course? I mean, they use them for fairings and as boat hulls, but I am a bit worried about the constant vibrations combined with the weight of the light/fender at the end and what that can do over time.
     
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  3. lindsaymac

    lindsaymac Can't reMember
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    Should be able to find a small enough assembly to do the job, faff, or knock one up yourself. Some pieces of sheetmetal and a few LEDs and Bob's your uncle.

    It's still snowing over there, isn't it?
     
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  4. faffi

    faffi A.S.A.N.

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    Well, not today, but frost is here to stay for a bit longer, unfortunately.
     
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  5. Felix

    Felix Idiot, pure and simple

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    Depends on how many layers and what type of mat you use Faffi. Most of the characteristics of frp comes from the choice of resin. Worth thinking about using metal inserts for your hard point fastenings though.
     
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  6. faffi

    faffi A.S.A.N.

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    After some thinking I have opted to make it part metal, part GFK. I will retain the metal fender where visible, and only make the required extension under the seat out of GFK. By having a layer on top of the fender and multiple layers underneath, I think the bonding should be strong enough since the load will be fairly low.
     
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  7. Felix

    Felix Idiot, pure and simple

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    Dynamic loads from vibrations play havoc with the interfaces between materials. Make sure you have nice clean metal and rough it up a bit. Avoid high shrinkage resins (polyesters?) and I'd go for an epoxy with a bit of flex or a slightly rubberised composition . (thixatrope?). From memory something like Huntsman ADH246TX/ADR246TX should work well but I can't speculate on availability or price.
     
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  8. faffi

    faffi A.S.A.N.

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    Good tip, thank you!
     
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  9. Felix

    Felix Idiot, pure and simple

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    Crap! It was about 2001/2 when I was playing with this stuff...time flies, eh?
     
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  10. faffi

    faffi A.S.A.N.

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    Very quickly :(
     
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