# Interior fiberglass bubbles **URL:** \ **Category:** Builder's Forum\ **Created:** [May 23, 2011, 11:36am UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500 "2011-05-23T11:36:51Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Grant\_Gardner](https://avatars.discourse-cdn.com/v4/letter/g/278dde/32.png) [@Grant\_Gardner](https://forum.clcboats.com/u/Grant_Gardner)\ **Post date:** [May 23, 2011, 11:36am UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/1 "2011-05-23T11:36:51Z")
I just finished my first boat, a Wood Duck 12. My first time out was great! No problems whatsoever. However, a couple days later I went out again and I noticed that the fiberglass on the bottom interior has bubbled up in several places. The bubbles are oval shaped, about 1/2"x2" and very brittle. I also fear I have a small leak. I did not fill the fiberglass weave completely with epoxy on the interior to aid traction and save weight. I want to be out on the water more than ever now, but don't want to make the problem worse. Does anyone know what is happening and how I can fix it? ---
**Author:** ![Grant\_Gardner](https://avatars.discourse-cdn.com/v4/letter/g/278dde/32.png) [@Grant\_Gardner](https://forum.clcboats.com/u/Grant_Gardner)\ **Post date:** [May 23, 2011, 7:37pm UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/2 "2011-05-23T19:37:34Z")
More info: there were no bubbles my first time out. Something unknown caused them to form. Anyone? ---
**Author:** ![Joey\_Schott1](https://avatars.discourse-cdn.com/v4/letter/j/a587f6/32.png) [@Joey\_Schott1](https://forum.clcboats.com/u/Joey_Schott1)\ **Post date:** [May 24, 2011, 4:20pm UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/3 "2011-05-24T16:20:28Z")
Can you send me some pictures of the affected areas? Can you tell if there is air or water within the blisters? I am also concerned about what is happening and hope that we can get to the bottom of the issue. ---
**Author:** ![Grant\_Gardner](https://avatars.discourse-cdn.com/v4/letter/g/278dde/32.png) [@Grant\_Gardner](https://forum.clcboats.com/u/Grant_Gardner)\ **Post date:** [May 26, 2011, 1:38pm UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/4 "2011-05-26T13:38:13Z")
Thanks for your concern Joey. The bubbles are filled with air and seem to be in a straight line, which is perplexing.  Here are some pictures. ![](http://i53.tinypic.com/nz2109.jpg) ![](http://i52.tinypic.com/2u8i9fs.jpg)  ---
**Author:** ![Patrick\_Mcfadden](https://avatars.discourse-cdn.com/v4/letter/p/bc8723/32.png) [@Patrick\_Mcfadden](https://forum.clcboats.com/u/Patrick_Mcfadden)\ **Post date:** [May 26, 2011, 9:28pm UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/5 "2011-05-26T21:28:11Z")
Looks like someone dripped some kind of liquid contaminant on the wood prior to glassing. Like oil or something else that caused adhesion problems. Cheers, Pat ---
**Author:** ![Joey\_Schott1](https://avatars.discourse-cdn.com/v4/letter/j/a587f6/32.png) [@Joey\_Schott1](https://forum.clcboats.com/u/Joey_Schott1)\ **Post date:** [May 27, 2011, 2:48pm UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/6 "2011-05-27T14:48:56Z")
Pat may be on to something. Possibly surface contamination or just plain old poor adhesion. Since there is no water in them, I would not worry. Could be that the air was always trapped and caused a blister once warmed up by th sun.   The fix is simple, grind the blisters off and patch the area with cloth and epoxy.  ---
**Author:** ![Grant\_Gardner](https://avatars.discourse-cdn.com/v4/letter/g/278dde/32.png) [@Grant\_Gardner](https://forum.clcboats.com/u/Grant_Gardner)\ **Post date:** [May 27, 2011, 6:08pm UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/7 "2011-05-27T18:08:53Z")
Thanks! I already put a coat of varnish on. Can I epoxy over the varnish?  ---
**Author:** ![Keith\_Powell](https://avatars.discourse-cdn.com/v4/letter/k/7ba0ec/32.png) [@Keith\_Powell](https://forum.clcboats.com/u/Keith_Powell)\ **Post date:** [May 27, 2011, 7:10pm UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/8 "2011-05-27T19:10:46Z")
If it wasn't something dripped on the plywood, perhaps there was some contaminant on the FG cloth... perhaps tape on a roll of FB? Just a guess. re epoxy over varnish... I would sand it off and put epoxy on epoxy, sand when cured and then varnish over. However, fix the bubbles first. Cut the bubbles out of the cloth with a sharp knife, or carefully use a rotary grinding tool, and then apply epoxy and a small FG patch. But... if you are have already varnished the areas, perhaps wait until further work needs to be done. ---
**Author:** ![James\_Doyle](https://avatars.discourse-cdn.com/v4/letter/j/b9e5f3/32.png) [@James\_Doyle](https://forum.clcboats.com/u/James_Doyle)\ **Post date:** [May 27, 2011, 9:34pm UTC](https://forum.clcboats.com/t/interior-fiberglass-bubbles/38500/9 "2011-05-27T21:34:03Z")
Nice WD! I had a similar thing happen on the bottom of my hull, but before I was done building. These guys are all right on about the soultion-you must grind down the bubbles, and recoat with epoxy. It doesn’t look too large or widespread that you’d compromise strength very much, but you can add a small piece of fiberglass cloth if necessary. It looks like you have a good, solid fillet built up. This is wat it looked like when I ![wrinkle](http://farm3.static.flickr.com/2095/5766786050_800e5d85f1.jpg)" mce\_src="" alt="" border="" hspace="" vspace="" width="" height="" align="" /\> sanded a bubble out: