Could someone please tell me about fiberglass gelcoat?

Discussion in 'Replica Props' started by Westies14, Apr 16, 2002.

  1. Westies14

    Westies14 Master Member

    Trophy Points:
    2,580
    A tutorial or a step by step process would be awesome. I can lay fiberglass matte just fine- but I want to be able to start with that nice, clean, smooth outer layer! Thanks in advance!

    -Douglas
     
  2. Lan Jenn

    Lan Jenn Well-Known Member RPF PREMIUM MEMBER

    Trophy Points:
    816
  3. hydin

    hydin Sr Member RPF PREMIUM MEMBER

    Trophy Points:
    2,305
  4. Westies14

    Westies14 Master Member

    Trophy Points:
    2,580
    Brandon, I'm definitely going to drop you an email, but if you'd like to post some general info here as well I'm sure some other members would appreciate it!

    -Douglas
     
  5. natty15d

    natty15d Well-Known Member

    Trophy Points:
    716
    Hi Douglas

    The big thing with Gel coat is what ever you do dont apply it in thin coats. If you use too thin a layer the heat from the curing fibreglass will cause it to crack or craze. Also if the coating is too thin it will leave bare patches in the mold. You want a GOOD covering of gel coat & you wont have any problems. [​IMG]

    Nathan
     
  6. Westies14

    Westies14 Master Member

    Trophy Points:
    2,580
    Thanks Nathan,

    I need to start at the beginning though, I'm afraid. Is gelcoat just a layer of liquid fiberglass resin brushed in without the matte, or is it a completely different product? If so, where do you buy it? I can lay down fiberglass matte well enough. The shape I am casting is fairly complex though (proton pack), I need the detail and smoothing help of a gelcoat layer...

    -Douglas
     
  7. natty15d

    natty15d Well-Known Member

    Trophy Points:
    716
    Gel coat is a completely different product from Fibreglass resin.
    For a start you can get it in different colours, ususally grey, white & clear can be obtained off the shelf from suppliers. Coloured ones can be made up by adding dyes to white gel coat. Your supplier should be able to sell you these along with the gel coat.
    Gel coat is like a thick gloss paint & takes longer to cure than fibreglass resin, or at least the stuff i use does.
    You want to really LOAD the brush up with gelcoat & use a 40/50mm brush. Use a cheap brush with white or clear bristles as if they come out they wont show up in the gel coat. Once your done just bin the brush.
    Work the gelcoat well into the corners as air bubbles can get trapped there.
    Gel coat is that thick it will even stick to vertical/inverted surfaces but it sometimes starts to come awat from sharp edges. Dont worry if that happens the fibreglass resin will seal it.

    Once the Gel coat has hardened give it half a day to fully cure as the fibreglass resin will start to break it down if you apply it too soon.

    Hope this helps
    Nathan [​IMG]
     
  8. Skyler101

    Skyler101 Sr Member

    Trophy Points:
    1,242
    I know that some people on the board mix body filler and resin together to make a cheap version of gelcoat. I have done this, and it worked very nice...

    -Skyler101
     
  9. Lan Jenn

    Lan Jenn Well-Known Member RPF PREMIUM MEMBER

    Trophy Points:
    816
  10. natty15d

    natty15d Well-Known Member

    Trophy Points:
    716
    Hi Brett

    Dont worry i didnt take it the wrong way.

    Im no expert with Gel coat, i was just trying to help out by pointing out things that i have found while using Gel coat.

    What i meant about the longer drying time is that Fibregleass will start to go off very quickly without much warning where as gelcoat has a longer usable time and gives you more of a warning when it starts to solidify. Living here in sunny Scotland things take a little lnger to cure.

    Thanks for the advice though its helped me understand gel coat a bit more. [​IMG]

    Nathan
     
  11. Lan Jenn

    Lan Jenn Well-Known Member RPF PREMIUM MEMBER

    Trophy Points:
    816
  12. Got Maul

    Got Maul Official Licensee RPF PREMIUM MEMBER

    Trophy Points:
    1,980
  13. Westies14

    Westies14 Master Member

    Trophy Points:
    2,580
    Nathan, Brett:

    Thanks so much for your input. What kind of equipment do you use to spray the gelcoat into a mold? What is the cost of the gelcoat supplies, on average? This is a great quick education for me, I really appreciate it!

    -Douglas
     
  14. Lan Jenn

    Lan Jenn Well-Known Member RPF PREMIUM MEMBER

    Trophy Points:
    816
  15. Westies14

    Westies14 Master Member

    Trophy Points:
    2,580
    Hi GotMaul,

    The gelcoat was not intended to be the final exterior of the pack. The surface can only pull as smooth as the master, and the shell is to be painted when it is pulled from the mold. A brush on resin would be just as good, better even if it is an easier application and just as durable... I am "exploring my options!" Please send me some more info on the products that you used if you get a chance! Thanks Jose,

    -Douglas
     
  16. Got Maul

    Got Maul Official Licensee RPF PREMIUM MEMBER

    Trophy Points:
    1,980
  17. kropserkel

    kropserkel Well-Known Member

    Trophy Points:
    706
    Now this is what I call contributing.

    Great information. Thank you very much.
     
  18. Got Maul

    Got Maul Official Licensee RPF PREMIUM MEMBER

    Trophy Points:
    1,980
  19. Westies14

    Westies14 Master Member

    Trophy Points:
    2,580
    Jose,

    I'm not sure I understand what you mean? I want to use the gelcoat to have a hard and perfect surface layer on the casting... Am I missing something about the fundamental nature of gelcoats? From what I understand, the process you're describing would achieve the same surface. Would it be as hard and durable? Are you saying that this process is much less expensive than gelcoating, and gelcoat's finish is something that I should pay for if I'm painting it- that the rest of the properties will be the same fundamentally?

    Agreed, this is a great and educational thread. Thank you to everyone who's posted so far, and to those of you who have PMed with additional information!

    -Douglas
     
  20. kimncris

    kimncris Well-Known Member

    Trophy Points:
    931
    jose's method looks and works great! I have seen the finished pack- and it has a nice smooth gray resin outer layer and then a nice hard backing of fiberglass for strength!

    -cris
     

Share This Page