fibre glass help

  1. steveo3002 Member

    Messages:
    4,903
    cambridge uk
    im trying to do a little diy project , ive made a mold or buck or whatever you call it that im laying the matt and resin into

    where i have sharp angles i stipple the matt down but its trying to straighten up again and wont stay around bends

    how do i fibre glass around bends...lighter matt i guess?
     
  2. the snooper

    the snooper getting older by the day

    Messages:
    20,014
    Location:
    Hull UK
    Are you putting enough resin on ?
     
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  3. Parm

    Parm Metal Tinkerer

    Messages:
    8,263
    Location:
    Towcester
    You need to wet it more. with enough resin it should hold to the shape of your mould
     
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  4. steveo3002 Member

    Messages:
    4,903
    cambridge uk
    was soaked

    im talking about external corners
     
  5. Yamhon

    Yamhon Member

    Messages:
    492
    Location:
    Yorkshire, UK
    If you cherry pick through this playlist from the Sail Life channel on YouTube; you'll see loads of use of GRP, I'm sure you'll be able to pick up some tips from what Mads as done on his boat.

     
  6. Yamhon

    Yamhon Member

    Messages:
    492
    Location:
    Yorkshire, UK
    Think I may have shared wrong link; look for 'Project Athena'

     
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  7. gaz1

    gaz1 Member

    Messages:
    7,850
    Location:
    westyorkshire
    how thick is your matt that your using?
     
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  8. Bullet2012

    Bullet2012 Forum Supporter

    Messages:
    908
    Location:
    Berks
    Are your external sides large enough ?
    Common practice is to oversize the external edges and then trim to size once released from the mould
     
  9. steveo3002 Member

    Messages:
    4,903
    cambridge uk
    i dont even know what spec it is...my guess is this is heavy stuff for big job and i needed tissue for small jobs

    pulled it out the mold now....good enough for a newbie lol , will put a picture on later

    whats the score with it staying sticky? will it dry off eventually
     
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  10. Yamhon

    Yamhon Member

    Messages:
    492
    Location:
    Yorkshire, UK
    From what I've seen on YouTube; might take 24-48 hours to fully cure.
     
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  11. fixerupper

    fixerupper Member

    Messages:
    1,476
    Location:
    Crete Greece
    I have always left it in the mould until it's hard , I would be concerned the shape would distort ...the speed of cure is down to the correct ratio of resin and hardener and the ambient temperature and humidity as far as I know ..
     
  12. steveo3002 Member

    Messages:
    4,903
    cambridge uk
    its rock hard...just makes your hands sticky handling it
     
  13. Parm

    Parm Metal Tinkerer

    Messages:
    8,263
    Location:
    Towcester
    Spot on
     
  14. carbon

    carbon Member

    Messages:
    1,105
    Location:
    S. Glos. U.K
    How old is the resin and catalyst?
     
  15. steveo3002 Member

    Messages:
    4,903
    cambridge uk
    its probably had a couple of birthdays now
     
  16. Burdekin

    Burdekin Chief Bodger

    Messages:
    4,552
    Location:
    Aberdeen
    Are you using polyester resin?

    Is it cut strand Matt or woven roving?
     
  17. Keith 66 Member

    Messages:
    1,546
    Essex UK
    The problem you describe with glass lifting off is caused by you not having a big enough radius on your plug or mould. Fibreglass does not like sharp corners either internal or external. Radius's are good! Dont matter how much resin you put on or how much you roll it it will lift off if the corner is too tight.
    Glassing into an internal corner that is square will often result in a line of air bubbles along the sharp edge, this can be avoided before you lay the glass on by squoozing a fillet of gelcoat thickend by cotton fibres into the corner first.
    I take it you are using a roller? The best type is a paddle wheel roller & it is used to consolidate the wet fibreglass & helps roll air bubbles out.
    I used to build an 18ft fibreglass rowing dinghy, she was a lovely boat & fast but was simulated clinker the mould having originally been lifted from a clinker built wooden boat.
    The overlapping plank edges or lands meant that to get a decent quality moulding all had to be carefully radiused.
    As there were 9 planks a side this meant approx 162ft run of gelcoat filler had to be applied. This increased the labour cost of laying up the hull by over 40%.
    I sold that mold & built a smooth skinned rowing boat, she is far easier to lay up & lighter too!
     
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  18. steveo3002 Member

    Messages:
    4,903
    cambridge uk
    polyester and cut strand

    i think keith is on the money there...needs a radius , not too worry it came out okay for what i need
     
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  19. The_Yellow_Ardvark

    The_Yellow_Ardvark If in doubt ask. Same rules for everyone

    Messages:
    10,367
    Location:
    UK
    On bends you need a radius, plus a finer matt.

    When you have stippled it, try using a foam roller on the bends and edges.

    I am no expert but have done a small bit of fibre glassing. Mosty car bumper repairs and a on one robin.
     
  20. The_Yellow_Ardvark

    The_Yellow_Ardvark If in doubt ask. Same rules for everyone

    Messages:
    10,367
    Location:
    UK
    When I last brought some kit, the supplier handed me a chart on how long it would be best to leave the resin to cure.
    Based on temp, humidity etc.
     
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