Results 1 to 21 of 21

Thread: What causes a bubble on side of hull and how to repair

  1. #1
    Join Date
    Oct 2018
    Location
    st louis MO
    Posts
    105

    Default What causes a bubble on side of hull and how to repair

    Found this bubble on outside of my hull.

    Any idea how it formed after year and half of use and boat always stored inside? Maybe from use on river hitting rocks?

    Few coats of interlux brightside over primer over fiberglass cloth.

    20221129_175652.jpg

  2. #2
    Join Date
    Mar 2007
    Location
    Still Above the Grass
    Posts
    8,041

    Default Re: What causes a bubble on side of hull and how to repair

    Was the fiberglass cloth set with epoxy? Which primer did you use, Pre-Kote or Epoxy Primekote. By Brightside, do you mean one-part Interlux Polyurethane?

  3. #3
    Join Date
    Oct 2018
    Location
    st louis MO
    Posts
    105

    Default Re: What causes a bubble on side of hull and how to repair

    I laid the fiberglass on and put two coats of epoxy on it.
    Used Epoxy Primekote and the one part Interlux Poly Brightside.
    This is the only spot this is happened so far.
    I'm going to cut it open with a blade and see if it's just paint.
    If it's the fiberglass, I guess I can just cut a small round piece of cloth and apply it with epoxy.

  4. #4
    Join Date
    Mar 2007
    Location
    Still Above the Grass
    Posts
    8,041

    Default Re: What causes a bubble on side of hull and how to repair

    The Epoxy Primekote is the right primer over epoxy.
    It doesn't look like a FG blister, but rather a blister in the paint.
    It would be good to know if the Primekote separated from the epoxy/FG, or if the Brightside separated from the Primekote.

  5. #5
    Join Date
    Apr 2015
    Location
    St. Helens, Oregon
    Posts
    5,181

    Default Re: What causes a bubble on side of hull and how to repair

    Was the epoxy well cured before you primed it? I screwed up once and tried painting over epoxy that was still curing...learned that lesson

  6. #6
    Join Date
    Mar 2007
    Location
    Still Above the Grass
    Posts
    8,041

    Default Re: What causes a bubble on side of hull and how to repair

    The data sheet for the Primekote specifies 3-7 days of cure time for the epoxy, then a wipe with YMA601V to remove the blush, then a water rinse, then sanding (80-120 grit).

    Some stearated sandpapers (no-load) will leave contaminants that will cause problems with the paint to primer bond.

  7. #7
    Join Date
    Oct 2018
    Location
    st louis MO
    Posts
    105

    Default Re: What causes a bubble on side of hull and how to repair

    It was the primer that bubbled off the fiberglass cloth. Luckily it's only a small spot, just odd it was that one small circular spot.
    Thanks for the help.
    First boat build so I'm sure I messed up somewhere at some point.

  8. #8
    Join Date
    Mar 2007
    Location
    Still Above the Grass
    Posts
    8,041

    Default Re: What causes a bubble on side of hull and how to repair

    That is good news actually. Probably just a bit of contamination on the FG, hopefully the only one.

  9. #9
    Join Date
    Jun 2000
    Location
    Madison Wisconsin
    Posts
    10,789

    Default Re: What causes a bubble on side of hull and how to repair

    Do be aware that there are also some of us (including the Gougeon Brothers the last time I checked) who believe that properly hardened, cleaned and sanded epoxy resin is a better primer than anything that you might add on top of it, and that using solvents to remove blush and thereby adding potential contaminants to a job which requires only water can be more problematic than helpful. I'm a big fan of Brightside over bare sanded WEST Epoxy and have never had anything other than great results with it. No primer used or needed. The same thing is frequently done with varnish over clear fiberglass for things like thousands of stripper canoes and kayaks, with obviously no primer and it works equally well. Just something to consider on your next build.

  10. #10
    Join Date
    Mar 2007
    Location
    Still Above the Grass
    Posts
    8,041

    Default Re: What causes a bubble on side of hull and how to repair

    Hey Todd,
    I've read several of your posts about Brightside directly over sanded epoxy/FG. I'm about ready to paint my CY, but right now it's bare okoume and will not have a FG overlay. My plan is to use thinned penetrating epoxy sealer (Total Boat), well sanded, and then Brightside directly over the sealer. Any advice would be appreciated. Thanks.

  11. #11
    Join Date
    Oct 2000
    Location
    Padanaram, MA USA
    Posts
    10,360

    Default Re: What causes a bubble on side of hull and how to repair

    Quote Originally Posted by TerryLL View Post
    Hey Todd,
    I've read several of your posts about Brightside directly over sanded epoxy/FG. I'm about ready to paint my CY, but right now it's bare okoume and will not have a FG overlay. My plan is to use thinned penetrating epoxy sealer (Total Boat), well sanded, and then Brightside directly over the sealer. Any advice would be appreciated. Thanks.
    I’ve had good luck with TotalBoat surfacing primer on naked okoume, followed by Kirby’s finest, another conventional alkyd paint.

  12. #12
    Join Date
    Jun 2000
    Location
    Madison Wisconsin
    Posts
    10,789

    Default Re: What causes a bubble on side of hull and how to repair

    I have heard that the diluted epoxy products can increase the lifespan of paint over bare wood, but I haven't tried them for that myself. I do consider much of the hype that comes with them to be total B.S. due to the fact that they contain such a large percentage of evaporating thinners, which will greatly reduce the chances that they will actually seal anything the way epoxy does. Do they actually improve the bond or lifespan of the paint enough to be better than more traditional methods and worth the extra cost? I really don't know. Drastically better than something like a coat of diluted paint or varnish, which would be a hell of a lot cheaper if you are just looking for something which soaks in a bit and gives you a foothold for the topcoats? I don't know, but I have my suspicions.

  13. #13
    Join Date
    Jul 2013
    Location
    Aquitaine
    Posts
    2,458

    Default Re: What causes a bubble on side of hull and how to repair

    Todd,
    Thanks for #9 & #12. I am close to painting my boat. Two coats of epoxy on ply. Local friend has done his with an undercoat, reccomended by a local builder. I was going for quality French paint alkilyde/eurythane that has a high UV resistance and does not need an u/coat. See what happens..

  14. #14
    Join Date
    Mar 2007
    Location
    Still Above the Grass
    Posts
    8,041

    Default Re: What causes a bubble on side of hull and how to repair

    I did a couple test runs with the Total Boat penetrating epoxy on okoume. When applied undiluted it wasn't noticeably thinner than regular S-3 epoxy and it didn't seem to penetrate at all. When I mixed it with 50% denatured alcohol it thinned out a lot and penetrated like crazy, leaving next to no surface coating.

    On previous builds I didn't use sealers or primers, just thinned Brightside for the first coat, but that was with the enamel Brightside, not the polyurethane. I'm uncertain if this thinned penetrating epoxy is necessary.

  15. #15
    Join Date
    Jun 2000
    Location
    Madison Wisconsin
    Posts
    10,789

    Default Re: What causes a bubble on side of hull and how to repair

    but that was with the enamel Brightside, not the polyurethane.
    I'm not aware of two different types of Brightside. The stuff I use has always been some sort of polyurethane as far as I know.

  16. #16
    Join Date
    Mar 2007
    Location
    Still Above the Grass
    Posts
    8,041

    Default Re: What causes a bubble on side of hull and how to repair

    Quote Originally Posted by Todd Bradshaw View Post
    I'm not aware of two different types of Brightside. The stuff I use has always been some sort of polyurethane as far as I know.
    You're right. It was the Interlux yacht enamel, not the Brightside.

  17. #17
    Join Date
    Oct 2000
    Location
    Padanaram, MA USA
    Posts
    10,360

    Default Re: What causes a bubble on side of hull and how to repair

    I recollect a West System EpoxyWorks article that describe some tests of highly solvented epoxy as a penetrating sealer. They used their own products and did not mention other commercial products.
    Their findings as I remember them:
    Adding solvents to epoxy increases its penetration from zero to minuscule. I cant remember the figures.
    Adding solvents to epoxy significantly increases its permeability. That is, whether it’s a good sealer. They suggested that when the epoxy cures, some of the solvents are trapped in the matrix and slowly escape over an extended period, leaving a porous matrix which is, not surprisingly, more permeable. They concluded that it was not an effective vapor barrier.

    I did a crude test and cast a 3 or 4 ounce puck of epoxy thinned 1:1. It cured hard and clear. I weighed the puck when it hardened and again months later. It lost over a third of its weight. I took this as confirmation of the Gougeons’ results and strengthened my skepticism of the miracle products with higher solvent content.

    I hope that someone can find that article.
    Last edited by JimConlin; 12-01-2022 at 10:18 PM.

  18. #18
    Join Date
    Jun 2010
    Location
    PNW, an island west of Seattle
    Posts
    3,480

    Default Re: What causes a bubble on side of hull and how to repair

    Quote Originally Posted by JimConlin View Post
    I recollect a West System EpoxyWorks article that describe some tests of highly solvented epoxy as a penetrating sealer. They used their own products and did not mention other commercial products.
    Their findings as I remember them:
    Adding solvents to epoxy increases its penetration from zero to minuscule. I cant remember the figures.
    Adding solvents to epoxy significantly increases its permeability. That is, whether it’s a good sealer. They suggested that when the epoxy cures, some of the solvents are trapped in the matrix and slowly escape over an extended period, leaving a porous matrix which is, not surprisingly, more permeable. They concluded that it was not an effective vapor barrier.

    I did a crude test and cast a 3 or 4 ounce puck of epoxy thinned 1:1. It cured hard and clear. I weighed the puck when it hardened and again months later. It lost over a third of its weight. I took this as confirmation of the Gougeons’ results and strengthened my skepticism of the miracle products with higher solvent content.

    I hope that someone can find that article.
    I applaud your experimenting with the material, Jim. And the results you found are interesting for sure. I wonder how the test might differ if one spread the thinned epoxy out over a wide surface... As one would do if sealing a transom or planking? The thinner build in a "real world" test would likely allow the solvents to escape much faster.

    Jeff

  19. #19
    Join Date
    Oct 2000
    Location
    Padanaram, MA USA
    Posts
    10,360

    Default Re: What causes a bubble on side of hull and how to repair

    True enough.

  20. #20
    Join Date
    Apr 2012
    Posts
    366

    Default Re: What causes a bubble on side of hull and how to repair

    I do not have the materials or desire to test thinned epoxy but will state my ideas as to a proper test,

    1. Use either commercial mix or self-thinned epoxy.
    2. Apply 2 coats to a 6 inch square of cheap 1/4 inch interior luan plywood.
    3. Weigh after 2 days to the smallest possible degree with an accurate scale.
    4. Weigh after 3 months and record that weight.
    5. Immerse in water for 3 months and weigh again.

  21. #21
    Join Date
    Oct 2009
    Location
    South Puget Sound/summer Eastern carib./winter
    Posts
    22,615

    Default Re: What causes a bubble on side of hull and how to repair

    Quote Originally Posted by ulav8r View Post
    I do not have the materials or desire to test thinned epoxy but will state my ideas as to a proper test,

    1. Use either commercial mix or self-thinned epoxy.
    2. Apply 2 coats to a 6 inch square of cheap 1/4 inch interior luan plywood.
    3. Weigh after 2 days to the smallest possible degree with an accurate scale.
    4. Weigh after 3 months and record that weight.
    5. Immerse in water for 3 months and weigh again.
    nobody got the desire to do all that

Posting Permissions

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