Results 1 to 10 of 10

Thread: Gel coat air bubbles

  1. #1

    Gel coat air bubbles

    Here is a question to the professional guys here who make mold everyday

    anyone please can explain why the gel coat makes small bubbles when trying to make a mold out of a hood?
    I used the Orange tooling gel coat for the mold

    i tried to put less hardener, i tried to wax it less times, i tried to give it more time to breath etc
    what the trick then? making me crazy.
    any help will be greatly appreciated
    Thanks

  2. #2
    Senior Member
    Join Date
    Jun 2008
    Posts
    779

    Re: Gel coat air bubbles

    I would say its the way you are applying it.

  3. #3

    Re: Gel coat air bubbles

    Quote Originally Posted by Greenmeansgo
    I would say its the way you are applying it.
    it did not matter if i pray it or roll it or brush it
    anymore info?

  4. #4
    Senior Member MacGyver's Avatar
    Join Date
    Dec 2004
    Posts
    3,047

    Re: Gel coat air bubbles

    To minimise air bubbles gelcoat should always be applied with a gun. It's almost imposable not to get air bubbles over a large area using a roller or a brush. For the most part I usually spray down 2 batches and check the thickness.

  5. #5
    Moderator FunnyWheels's Avatar
    Join Date
    Nov 2002
    Location
    Tampa, FL
    Posts
    8,151

    Re: Gel coat air bubbles

    It sounds to me like it is too much wax. I would recommend wiping down a little better and mixing the hardener a bit more .

    Dave
    If you're not confused, you're not paying attention.

  6. #6
    Senior Member ITALIANKNIGHTRIDER's Avatar
    Join Date
    Jan 2005
    Location
    Tx
    Posts
    2,995

    Re: Gel coat air bubbles

    if you are not set up for a paint gun system an have to use a brush, Do not brush back an forth ,go one direction ,because it make thick spots an air bubbles ,wash the brush in acetone so it does not get stiff an hard , Good Luck
    In the USA if you pay a company / person to start a plug, then it,s your plug and work ,it is not theirs to sell or trade !!

  7. #7
    Senior Member
    Join Date
    Feb 2005
    Posts
    611

    Re: Gel coat air bubbles

    lets see, mmm never had this problem, don;t think is the wax, sounds to me like your mix isn't correct, could be your temperature too extreme , mmm.

  8. #8

    Re: Gel coat air bubbles

    Quote Originally Posted by carspancho
    lets see, mmm never had this problem, don;t think is the wax, sounds to me like your mix isn't correct, could be your temperature too extreme , mmm.
    what kind wax do you use? i mean what brand? please
    i did a mold before and it came very good but this time is not

    Thanks for all the help and ideas guys

  9. #9
    Senior Member
    Join Date
    Jan 2008
    Posts
    746

    Re: Gel coat air bubbles

    three main factors, temp and the amount of wax and type of gel coat you use.

    If your using alot of wax and forgetting to wipe it off after it is dried, it will spread it self like Moses and the red sea.
    I use paste wax, it releases better than carnauba wax. Layer of paste wax, PVA and another layer of Paste wax left sit for 20 mins wipe off.

    Temperature is a major factor in bubbles and lifting. If it is really hot out and your mixing more catelyst in to the mix, the heat from the heat from the chemical reaction with cause it to shrink rapidly causing it to appear like air bubbles and lifts from the molds surface. Or you could be adding the second layer of gel coat to early before it has time to fully cure, adding another layer during the its gel state can cause it to bubble, lift, or wrinkle.

    Type of gel coat you use is important too, when making a mold you would want to use a tooling gel. It is much denser and stronger to impact that regular gel coat. It is a thicker gel coat.

    Right after when you have spread your first layer on and before it has time to cure. Use cotton flock, just sprinkle it on, the next day just brush the excess off and you won't have to sand the surface down before adding another layer. The cotton flock give the second layer of gelcoat something to grab on too and helps prevent and voids that can happen.

    Anyways hope this helps, good luck

  10. #10

    Re: Gel coat air bubbles

    Thanks Prototype for all the info
    its great help

Similar Threads

  1. Spraying Gel Coat
    By Don in forum Technical Discussion & Question
    Replies: 12
    Last Post: 02-03-2012, 11:12 PM
  2. Paint or gel coat.
    By punkit in forum Technical Discussion & Question
    Replies: 4
    Last Post: 10-10-2008, 03:08 PM
  3. gel coat or no gel coat -or willing volunteer needed
    By detroitbrit in forum Technical Discussion & Question
    Replies: 12
    Last Post: 02-02-2008, 09:44 PM
  4. applying a gel coat
    By HollowMan in forum Technical Discussion & Question
    Replies: 11
    Last Post: 02-15-2003, 06:42 AM
  5. Questions about Gel-coat ?
    By AmbeBock in forum General Kitcar Chat
    Replies: 6
    Last Post: 04-25-2002, 01:13 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •