View Full Version : Fiberglassing
05-11-2009, 03:18 PM
I was just told by a guy that does alot of fiberglassing that a trick to getting the cloth to relax and laydown is to mist water on to the cloth with a spray bottle (windex bottle etc...) then apply a thinned first coat of epoxy or poly if you choose. The water does not affect the poly or epoxy and the acetone solvent disipates the moisture. Anyone doing or done this????
05-11-2009, 03:29 PM
Never done it and would need a lot of convincing to try.Normally moisture spots on the glass cloth show up as opaque white patches in the finished laminate.
05-11-2009, 04:06 PM
I'm with John on this one. I'm appalled at the very idea. We went to a lot of trouble to keep our cloth warm & dry. Moisture in epoxy causes blushing & may inhibit setting. Moisture in polyester invites boat pox. In fact, here in Godzone, Marine Regs. for building to Survey standard (& why would you build to less?) prohibit laying up if atmospheric moisture content exceeds a set limit. I forget the exact number, but it meant that without climate control we couldn't lay up if it was raining outside.
05-11-2009, 04:14 PM
My understanding is that the fiberglass cloth is coated and you don't want to touch it with bare hands or anything else to avoid leaving visible marks or stains.
05-11-2009, 04:26 PM
Many shops have glass on rolls that are so filthy with dust that it's a miracle the cloth adheres to anything!
05-11-2009, 07:31 PM
Fortunately, my glass rack is in a place that has a fairly stable atmosphere and not very much dust.
I would not dream of wetting glass prior to layup.
05-11-2009, 07:52 PM
The volan sizing that is common on most of the fiberglass cloth you buy is water soluable. It is what allows the resin to penetrate and wet out the cloth. Messing with it is a very bad idea and quite risky. P.S. Don't buy any boats that your friend did the layup on.
Clinton B Chase
05-12-2009, 07:26 AM
I second Todd. What the heck weight material is the original poster referring to?
Also, as you get exotherm...that water needs to warm up and vaporize...how does it get out (this would be a problem! in a thick laminate)
This idea is crazy.
05-12-2009, 07:49 AM
if you must "relax" the f'glass to make it lay better, give it a bath in acetone..LET THE ACETONE EVAPORATE!!...then do your layup. This works especially well if using mat. If you are working smaller areas, consider prewetting the f'glass then add the piece into your layup
05-12-2009, 08:22 AM
I was just told by a guy that does alot of fiberglassing that a trick to getting the cloth to relax and laydown is to mist water on to the cloth with a spray bottle (windex bottle etc...) then apply a thinned first coat of epoxy or poly if you choose. The water does not affect the poly or epoxy and the acetone solvent disipates the moisture. Anyone doing or done this????Not a chance. He can't mean water, unless his goal is to ruin your project. If by "relax" he means stretch smoothly over the surface, I suspect he is glassing without an underlying saturation coat of resin.
BTW, never, never use polyester resin to glass a wooden structure. It will fail, in time, and delaminate if the wood gets wet. BTDT.
05-27-2009, 08:58 AM
I just built a cedar lapstrake on oak frame , varnished everything except the bottom on which I used antifouling bottom paint. I have many leaks whick I have caulked but I still have some, so I decided I want to fiberglass the bottom. I guess I have to remove the bottom paint first. Anyone have any ideas for removal, and then fiberglassing bottom?
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