Gelcoat wrinkled/lifted Question

Discussion in 'Fiberglass and Composite Boat Building' started by pescaloco, Jan 4, 2014.

  1. pescaloco
    Joined: Feb 2006
    Posts: 301
    Likes: 10, Points: 18, Legacy Rep: 81
    Location: so. california

    pescaloco Senior Member

    Hello guys

    I thought I had a pretty good handle on the use and application of Gelcoat
    but ran into a situation.

    I built integral fuel tanks for my boat with Vinylester resin and sealed the interior of the tanks with Gelcoat.

    I rolled on a coat of unwaxed Gelcoat catalyzed at 2% let kick for 2 hours at 70 degrees F then rolled another coat with wax and had the second coat wrinkle and lift badly in some areas.

    I ended up scraping most of it off but what a nightmare

    My question is two fold was my recoat time too soon and how concerned should I be about wax contamination from the parts I didn't scrape off. Can I acetone wipe and sand and be ok.

    what is the recommended recoating time to roll multiple coats with a finishing flow coat.

    Thanks Guys
     
  2. waikikin
    Joined: Jan 2006
    Posts: 2,408
    Likes: 160, Points: 73, Legacy Rep: 871
    Location: Australia

    waikikin Senior Member

    Maybe styrene "vapors" entrapped/dammed in the tank, usual practice is to blow a fan across the top to shift some fresh air in. Worth a try... is it worse deeper into the tank? 70F is about 21C nearly ideal, one test is the "squeak" of an extended middle(rude) finger across the gel.... not to scientific but dont go again b4 it squeaks!
    Jeff.
     
  3. pescaloco
    Joined: Feb 2006
    Posts: 301
    Likes: 10, Points: 18, Legacy Rep: 81
    Location: so. california

    pescaloco Senior Member

    Thanks for the reply

    there is a lip where the lid goes on and the wrinkles were on the vertical walls and under the lip. I was wondering about vapor entrapment.

    How concerned should I be about wax contamination where I was unable to scrape off the effected gelcoat
     
  4. waikikin
    Joined: Jan 2006
    Posts: 2,408
    Likes: 160, Points: 73, Legacy Rep: 871
    Location: Australia

    waikikin Senior Member

    Just thinking out loud,.... for the vapor issue I'd expect it worse deepest in the hole unless there's a variation of your thickness & the bottom thick & kicked nice & the sides thin & affected. There's nothing wrong with giving it a good scuff up before going again. What fuel is going in the tanks?
    Jeff.
     
  5. pescaloco
    Joined: Feb 2006
    Posts: 301
    Likes: 10, Points: 18, Legacy Rep: 81
    Location: so. california

    pescaloco Senior Member

    The thickness was pretty even I think the bottom flat was a little heavier but the sides were pretty thick.

    In some places it wrinkled just under the out turned lip and others most of vertical wall, but honestly I seemed to notice the wrinkling start at the top not the bottom

    The tanks are for Diesel fuel

    Thanks
     
  6. redreuben
    Joined: Jan 2009
    Posts: 1,905
    Likes: 175, Points: 63, Legacy Rep: 349
    Location: South Lake Western Australia

    redreuben redreuben

    The usual causes of triping (wrinkling) are under cure from under catalysing or too thin a layer or insufficient cure time.
    Your catalyst level is ideal, my guess would be from under cure, as mentioned ventilation of the styrene is critical, given where it occurred I would suspect the gelcoat was too thin there and I would double the cure time at least before re-coating. With the first application being unwaxed 24hrs is no problem.
     
  7. redreuben
    Joined: Jan 2009
    Posts: 1,905
    Likes: 175, Points: 63, Legacy Rep: 349
    Location: South Lake Western Australia

    redreuben redreuben

    Also; it is imperative that the second coat goes off quickly to minimise the styrene attack, keep the catalyst level up and use heaps of ventilation.
    Good luck.
     
  8. pescaloco
    Joined: Feb 2006
    Posts: 301
    Likes: 10, Points: 18, Legacy Rep: 81
    Location: so. california

    pescaloco Senior Member

    In retrospect I think it was due to under cure, because it started to wrinkle soon after the second application went on

    After a day of scraping and sanding I recoated the tanks this time with good ventilation and adequate cure time.

    All worked out well

    Thanks guys
     
  9. bjviking
    Joined: Oct 2009
    Posts: 10
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Ireland

    bjviking bjviking

    Using Flowcoat in Diesel Tank

    Hi.
    Looking for some advice. I have built a polyester fibreglass tank for holding diesel. I am planning on coating the interior with flowcoat. As flowcoat has a wax additive to enable tack free cure, could this contaminate the diesel.

    Any thoughts?
    Regards.
     
  10. iceboater
    Joined: Jan 2011
    Posts: 67
    Likes: 11, Points: 0, Legacy Rep: 116
    Location: Iceland

    iceboater Junior Member

    Your flowcoat has paraffin wax in it. Paraffin can be found in most diesel fuel up to 20% of volume. So you do not need to worry.
     
  11. bjviking
    Joined: Oct 2009
    Posts: 10
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Ireland

    bjviking bjviking

    Thanks for the reassurance.
     

  12. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 199, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

    I guess in the UK, paraffin refers to the liquid, kerosene. I don't know if the paraffin wax in gelcoat is the same thing.
     
Loading...
Similar Threads
  1. aaronhl
    Replies:
    1
    Views:
    27
  2. Laurance
    Replies:
    15
    Views:
    602
  3. TBC Marine
    Replies:
    3
    Views:
    304
  4. mrdebian
    Replies:
    6
    Views:
    450
  5. aaronhl
    Replies:
    11
    Views:
    545
  6. aaronhl
    Replies:
    5
    Views:
    522
  7. JackyJ243
    Replies:
    8
    Views:
    1,649
  8. Nachtvlinder
    Replies:
    2
    Views:
    596
  9. Scuff
    Replies:
    12
    Views:
    1,494
  10. doogymon
    Replies:
    12
    Views:
    1,121
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.