View Full Version : overhead fiberglassing

01-21-2004, 11:32 PM
am having to fiberglass my 37 ft boat after peeling;anyone have info on overhead glassing techniques/vacuum bagging .have heard that 3m adhesive is useful.thanks sd

Ian McColgin
01-22-2004, 07:35 AM
The Viatsais method uses a mastic between the wood and the first glass layer, often rod bundles that resembe planks.

If you're glassing a wooden hull, look to some of the other posts as to what you need to worry about to ensure that you're not ruining the boat.

It's most unusual to get good results from a layer of glass over a hull unless the boat was originally a composit or molded structure and you're using the glass to protect the surface.

Make a good layout plan that maximizes rolling convenient sizes of cloth. 48" wide works for me. Probably a bit of an angle from gunnel down to keel. Paint a thin layer of epoxy where one bit of glass will go down. Time yourself carefully. Just as it's ready to kick, staple one end of the first little roll to the gunnel and roll it down on the wet epoxy. Work with a roller to get it well stuck everywhere as the epoxy goes off. Repeat many times.

Overlap the edges a little. As the epoxy on your latest gets almost firm, trim it with a utility knive on or just a hair inside the edge of the lowwer (earlier) panel. Peal off the overlap. This will much reduce annoying grinding.

Sometimes even with all this you'll need to hold panels up. If you can get rolls of semistiff mylar, you can lay them on the glass and staple right through.

It is a very slow and messy process and you may well end up with a chemical sensitivity.


01-22-2004, 10:29 AM
No kidding, a light spray of 3M 77 adhesive ( Home Depot or office supply place will have it) on the overhead surface will hold the cloth in place while you epoxy and won't interfere with the bond. Experiment and you'll see how much, how little really, is needed.

01-22-2004, 11:20 AM
Gentleman don't sail to windward nor glass overhead!

No kidding Buddy? I had to think on that one a bit to get beyond first reaction but a very light mist might indeed hold the glass but not seal the wood to prevent the goop from penetrating. Very interesting. As you say, careful testing would be in order.

01-22-2004, 06:14 PM
Works like a charm IF you don't use more than just the least mist it takes to hold it up which is not much. Don't get ahead of yourself and do too big a section at a time. Let the spray set a minute to get its ultimate window of tacky- just like Goldilocks, not too short or too long. If you're doing a long piece, you can use a thin batten and staple gun to hold you the "wet" edge of what you've stuck up and not let the weight of yet unfastened cloth pull away what you've accomplished. Then pull those out before you epoxy.