Hi there, guys.

What I tried to do was vacuum bag some under-deck reinforcement layers of glass. Actually, it wasn't a bag, but a flat panel rig, where I wanted to lay glass on only one side of the wood. It's probably easier than a full bag, but I haven't got there yet.

As mentioned to Chip, though, there's more to it than simply turning on the vacuum pump.

In my case, I applied the strongest vacuum I could until the epoxy set up. That's too much! The vacuum drew too much epoxy out of the 3 layers of glass, leaving a starved look to the cloth when it was done.

Unfortunately, with all the stuff on top of it, one can't tell this is happening until it's too late.

It's clear to me that a regulated vacuum is needed, and for a shorter time as well.

Regulating the vacuum does not appear to be as hard as it seems, nor do you need to buy a vacuum regulator device. I've done the job since, using another T-connector between the project and the pump, and cracking open a small valve on it. That allows enough vacuum regulation as far as I can tell with the gauges I use.

What I'm really waiting for is a 50-page publication from WEST, which I think will lay it all out for me. I ordered it locally, and this will take several more weeks. I don't have it in front of me, but I think it's titled, "Vacuum Bagging Techniques."

For the peel ply I use nylon taffeta from the local fabric store. It is cheaper than the dedicated stuff I've seen in the fiberglass supply stores, yet it seems to do a fine job. It may even be re-usable.

For the absorbant material I use a couple of layers of paper towels.

The other point on which I'm unclear now is how much epoxy to leave in the glass before laying on the vacuum apparatus. It would make sense to squeegee the excess out first, the same as if you weren't going with vacuum, it seems, but then what do you really need the absorbant material for, then?

Still, I think the answers are there, and from the little experimentation that I've done, it's worth pursuing for the moment. It does leave a marvelous smooth surface, with the texture of the taffeta material.

I'll summarize the publication when I finally get it.

cheers,

Pete,
in Snohomish