Fiberglass bubbles.... how and why???

[kaptainkoz]

I dont understand how or why this happens. I am using vinylester resin and 1708 biaxial fiberglass. The surface is the hull of my 1979 246 CCP which is polyester resin. The surface was sanded and wiped with acetone before being wet out with the resin, glass applied, then more resin to wet out the biaxial. I have a stiff bristled brush which i use to stipple the resin further into the cloth until its well coated. I walk away and everyting looks great. I come back 45 minutes later to a bubble or a whiten spot that doesnt look as dark as is originally did.


What am i missing here?

Thanks!!

[RickK]

I've had that happen in epoxy too and not sure why.  

[florida196]

Has happened on my build to also using epoxy resin I found that after laying everything up and being happy with it I'll go back in about an hr after everything starts to tack up and you can usually work any bubbles out

[saltfly]

Did you use a spreader and glass roller? I find it's not the rosin your using but the 1708 needs to really be worked down. the roller lets you put pressure on the 1708. Just my opinion.

[dirtwheelsfl]

Pics of the glass dry?

[seabob4]

Did you use a spreader and glass roller? I find it's not the rosin your using but the 1708 needs to really be worked down. the roller lets you put pressure on the 1708. Just my opinion.

I was gonna say something about rollers, but I figured that was too obvious...

[Callyb]

Koz, if you are getting quite a few areas lifting like that I agree that the resin may not be getting woked through the cloth enough in those areas. After looking at you build thread I see what you are using for wetting out. I think that may be the problem. I would try using a laminate roller to work the resin into and through the glass.

[RickK]

I had everything appearance-wise saturated and hard rolled everything as usual and I'd come back and on the side of the stringer there'd be a big bubble.  I jump in the hull and roll away and it'd look nice and I'd walk away just to come back to a bubble again.  Ended up sitting there and rolling it down when it started to pucker until the resin kicked.

[seabob4]

I would imagine there is more to this than meets the eye.  Everyone involved here is fully cognizant in regards to saturation, rollers, what "air" looks like, all that good chit.  So I would suggest we look deeper, in regards to a possible out-gassing situation due to a chemical reaction, something like that.

Think about it.  If you don't roll out the trapped air, it can't get out.  Therefore, how does air get in?  Unless it isn't air, but rather a gaseous by-product of a chemical reaction that wasn't planned on...


Just a couple pennies there...

[kaptainkoz]

Thank you everyone. I think I will go a bit heavier on the resin and use the roller more. I'm using a stiff bristled brush which seems to get the glass down well. In trying to get a few large pieces down it doesn't leave me alot of time to babysit a piece with a roller. It doing a bit of Internet research, I think the bubble in the photo is a gas out as it was the end of the pot and I laid the resin a bit heavy to use up what I had, so it definitely wasn't resin starved. The one in the photo was the worst one of the whole build so far so I think its going well. I just wanted to make sure I wasn't missing something. Thanks for the great advice.

[saltfly]

This may not be the problem, but It works for me. All rosin out gases. So if you stretch the glass when pushing and pulling as you apply the rosin and really soak the cloth. there is no place for the out gas to escape. So it tries to rise and pushs up the glass and forms a bubble, just like a ballon. So when I see a bubble starting to form. I use a razor knife and a spreader to cut the cloth. Then roll it down so it over laps. It doesn't weaken the finished lay up and solves the problem.

[kaptainkoz]

Thanks Salt fly, good idea. Thank you!

In thinking about all that was written here, I am even thinking of going so far as to wet out a new surface and let the resin set for an hour or so, then go back and wet it again and lay glass. I add my own wax as needed so obviously that first "primer" coat would be without wax and still provide a good bond. If there is anything on the surface that has to gas let it do so without fiberglass to bubble. The stringers and the keel were reinforcement in most cases so im not super alarmed at a delamination bubble here and there. However, the next serious phase of glassing for me is the transom and it has to be rock solid perfect.

[seabob4]

Steve,
I have to believe that something chemical is going on here, perhaps with the use of vinylester over the old polyester laminate.  I was at the OEM level up until a few years ago, WC/AS, Stamas, Hydra-Sports, Intrepid, Pro-Line...I've seen literally thousands of hulls, decks, stringer grids laid up or installed.  Other than the normal rolling out of the glass, no other "special" steps were necessary to preclude "bubbles" like you are experiencing from forming.  This was always based on "polyester with polyester" or "vinylester with vinylester".  Builders don't mix the 2, it's either all poly or all vinyl.  I did a little search on possible incompatability issues that may cause undesired results, but came up empty.

Adding more resin isn't going to help.  You'll just end up with resin-rich laminates, which do nothing but add un-needed weight to the boat.  You've worked quite a bit with glass, you can tell a properly wetted out piece of glass...opacity all throughout, no hints of "white" here and there.  So you're doing the job correctly.  There's just something that tells me the new stuff your putting down and the old stuff it's going on don't get along well together...

[dburr]

Believe it or not, to much resin will actually cause the glass to float off the surface and the laminate will not be as strong because the resin is brittle and weaker then the glass..  Keep,on doing what you are doing..  There just seems to be a pocket of crap that was determined to ruin your day..

[seabob4]

What Dave said could be entirely possible.


What you might want to do is contact Composites One on their tech help line and run it by them.  I'm sure they could shed some light on the subject...