Need Some Serious Help...

Islandtrader · #1 03-08-2010, 10:54 AM

I have had some fiberglass layup failures lately and I don't know what is going on.

Lets get the variables out of the way. Same resin, same epoxy nothing changed. Layup early after noon temps. around 65-70 no sun. Prime area with epoxy then lay up 4 oz. cloth wet it and make sure everything is squeegeed tight.

Next day go to check it, all dry looks good. Give the excess mat a tug and it comes off like it was wax paper.?????

The epoxy is still on the surface strong as ever and basically can not be chipped off. So the epoxy is not failing its something I am doing or its the cloth. The weird think is that I have used this cloth the day before and it is holding. A few weeks ago I used it and the failure happened.

I know it is most likely something I am doing but its got me stumped.

I am getting tired of doing the same spot over and over and now I am getting gun shy thinking oh oh I have laid up a lot of stuff....is it going to come apart.

HELP! [img]/forum/images/graemlins/tongue.gif[/img]

NoBones · #2 03-08-2010, 11:02 AM

Terry,

The cloth could have moisture in it, or try mixing a
little "hotter" MEK in your resin. 11 CC per qt. is the norm.
Humidity can ruin your day for sure.

See ya, Ken

Islandtrader · #3 03-08-2010, 11:08 AM

Using epoxy not the other stuff. I thought it might be moisture in the cloth but it has been under closed roof and doors...plus no humidity the last few months.

I would hate to think I have to put that stuff in a dryer first

strick · #4 03-08-2010, 11:50 AM

When you say the "epoxy is still on the surface" are you saying that the epoxy is still stuck to the substrate or the cloth? Have you ruled out a problem with the material you are trying to bond the cloth to? Sorry I'm not all that clear about whats coming apart. Also are using an old batch of material that has been sitting a long time?

strick

Islandtrader · #5 03-08-2010, 03:24 PM

Quote:

When you say the "epoxy is still on the surface" are you saying that the epoxy is still stuck to the substrate or the cloth?
strick

The epoxy is bonded to the surface. If you did not know any better you would think you were looking at the fiberglass cloth, a perfect mold. The epoxy is bonded to the old gel coat no peeling or chipping. The 4 0z. cloth now looks like a piece of parchment cloth.

Chemicals are fresh (less than 6 months).

BigLew · #6 03-08-2010, 06:11 PM

Could the cloth have been exposed to some oil or other bonding preventing substance. Also is the cloth being put down in "yet to cure" epoxy and then wetted out from there?

I am no expert, but just thinking out loud, so to speak. Good luck. I am sure someone else has better information than me. They'll chime in shortly, I'm sure.

Hookdude · #7 03-08-2010, 08:10 PM

Are you using MEKP (Methyl Ethyl Ketone Peroxide)or just MEK (Methyl Ethyl Ketone)?

Without the Peroxide, it won't kick. (I found this out the hard way!)

Cheers,
Bob

Tarpun · #8 03-08-2010, 09:21 PM

I recall reading somewhere that some cloth is not compatable with epoxy due to a special treatment to allow better bonding with poly resins. I'll tryy to hunt the article down. Dave

Islandtrader · #9 03-09-2010, 09:55 AM

I talked to a factory rep late yesterday regarding the above problem.

After going thru a checklist we narrowed it down to using the wrong cure hardener for the weather. I was using the slow hardener in temps. that were approx. 65 air temp. the reality of it was that the area I was doing most likely was only 60 or so and the temps. dropped quickly in the late afternoon below the 65 mark. Now keep in mind that in southern FLA. These type of temps. are not usually around and I forgot that just because outside feels warm the boat never warmed up. So what happened was that the epoxy kicked on the surface but ran out of the final heat when the cloth was drying.

The point was proven when I used a fast hardener and everything came out OK. The reason I don't like to use a fast hardener for layup is because it kicks so fast that you can not do a larger area.

OH WELL a lesson to be learned. If nothing else at least everyone reading this thread will put the solution in there data bank and not do what I have done. At least all I have to do now is scuff the epoxy re-coat and then lay up more glass. Better than a sticky gooie mess.

76Red18 · #10 03-09-2010, 11:02 AM

Glad you found the problem. I've had problems with concrete curing correctly this winter also. Never would have dreamed it would be too cold to pour in Florida