pot life of epoxy

[will guthrie]

I'm gluing a second layer of 1/8 inch marine ply over a layer already on the roof of my trailer and was gonna use East system epoxy ( based on west system but cheaper- sold by Noah's Marine in canada), with slow hardener and 403 adhesive filler. I have 5 sheets to glue down that are 48x 70 which I'll glue down one at a time. I'm wondering how much epoxy I can mix up without the volume of epoxy generating heat and setting the epoxy before I can get it on the ply and the ply screwed down. I'll need to use quite a bit to cover the 48x70. Perhaps I should mix up a couple batches instead of one big one. Morning temps here in Tucson are about 80 and so I gotta work pretty fast. thanks for the help

[tonyj]

Mix up several batches in shallow wide mixing containers as you go along. After you put it on the ply, you have plenty of time to mix another batch and finish applying. Nothing more frustrating and expensive than to mix up a large batch only to see it kick off in the container before you even get a chance to use it.

[Miriam C.]

Here are some suggestions from a limited experience.

Get a cheap squeegee to spread it with. Treat it like a pour if you can. Might just slide off. Pretend you are washing a window to put it on..

try doing it at night and on a humid day. That sure slows it down here.

[Juneaudave]

For that much epoxy...get an assistant to help!!!! You can be applying and the assistant can be mixing and giving the extra hand. You'll be glad you did.

On a more general note....are you set on using epoxy to bond those sheets?

[Steve_Cox]

To spread the epoxy fast, use a foam roller made for it. You might try pre coating one surface of the two to be joined and let it cure. Like everyone else says, the more spread out the epoxy is the slower it generates heat and cures. Slow hardener, you shouldn't have any problems if you mix 4 to 6 oz batches in a wide shallow container.

[asianflava]

If you pour it into a roller pan it will last a whole lot longer than a mixing tub. East systems Epoxy

[tk]

Ditto on wide, shallow containers like pie pans or paint pans. If you use foam rollers or foam disposable brushes be aware that they start to disintegrate after some usage--have more than one on hand, probably several for a large area. And, there are differences in quality between different brands of foam brushes and rollers, some last better than others.

Best,
Tom

[Alphacarina]

Yes, the shallower the pan the longer it lasts and if you keep it cool (stick it in a fridge or icebox while you're not rolling it) you can really extend the life of it too

For laminating purposes, I roll a coat on both pieces and most of that will sink in. Then, when I'm ready to stick the two together, I roll a heavy coat on one piece and then clamp and screw them together. I've made some very heavy duty curved roofs on boats from 3 pieces of 1/4 inch ply that way. Because they're laminated into a curved shape, you can walk all over them and even jump up and down on it - Incredibly strong

Don

[asianflava]

For laminating purposes, I roll a coat on both pieces and most of that will sink in. Then, when I'm ready to stick the two together, I roll a heavy coat on one piece and then clamp them together.

I used the same method when I glued together the faces to my sidewall frames. The only difference was that instead of a second heavy coat, I spread epoxy thickened with microfibers them right before clamping.

[doug hodder]

I'm with Rocky...some slightly thickened epoxy won't "soak" in quite like the plain catalyzed product. I use the silica to thicken it for structural uses, it's harder to sand, but gives better bonding than a thickening agent used for fairing. Works fine for laminating especially for things that are going to be exposed to the elements. For interior, like birch paneling onto the ply...I just use the titebond, and drizzle it all over and weight it down. A lot cheaper. Doug

[angib]

Rocky's microfibres (actually tiny strands of cotton) are the strongest thickener for bonding, because they have some length. Silica is hard but not very ductile (so it cracks easily), and lightweight fairing fillers are neither hard nor strong.

Andrew

[will guthrie]

wow, thanks for all the replies. I knew there was some good experience out there. I think I'll roll on straight epoxy to coat then before bonding will put on another coat mixed with west sys. 403 adhesive filler. Thanks again.