Waterproofing A Plywood Box

[Too_Many_Tools]

I am interested in hearing suggestions in how to waterproof a plywood box.

The box in question is approximately the size of a phone booth and unfortunately it was made with interior plywood (not by me). When it was rained on for the first time, the outermost ply began to separate and lift.

I plan to sand the box to remove the portions of the outer ply that have raised but will need to coat the box with something to prevent further damage by moisture.

I should also mention that the box will in the end be painted in a white color to keep the contents of the box cool.

Any suggestions?

Thanks

TMT

[Jim]

Replace this box with one made out of exterior or marine plywood is my idea. Jim

[Phisherman]

There are marine epoxy finishes that protect well. Some kind of sloped shingled roof, corrugated fiberglass or rubber membrane on top will help too. Even with that, regular maintenance will be required.

[Too_Many_Tools]

"Replace this box with one made out of exterior or marine plywood is my idea. Jim "

That was my first thought Jim but unfortunately it was specially built for a piece of equipment....so I am stuck with using the original box.

Thanks for the suggestion.

TMT

[Joe Barta]

I'd say any paintable coating will probably fail sooner or later.

For a more permanent solution you could try single ply rubber as used in the commercial roofing business. It's pretty easy to apply, lasts a long long time and there are types that come in white. Contact your local commercial roofing supplier for information (a roofing supplier... not Home Depot etc.)

Joe Barta

[Zz Yzx]

[Too_Many_Tools]

A related question....it was suggested that I sheath this box in some type of lightweight, insulating, waterproof sheet good...again to help keep the contents cool and the box dry....any suggestions as to what might be out there?

TMT

[Eugene Nine]

by the time you put that much work into it you could just rebuild the box with new plywood. Just do one part at a time using the old as a remplate.

[phildcrowNOSPAM]

How about, um, plastic cardboard? I'm not sure of the industry name, but it's a plastic sheet good that is constructed exactly like corrugated cardboard. Gluing it on might be a good idea.

HTH,

-Phil Crow

[Frank Boettcher]

Glass it over. Not too hard, not too expensive and will last longer than any coating you can put on it.

[J T]

Sun, Jan 15, 2006, 9:47am (EST-3) too_many [e-mail] (Too_Many_Tools) tosses out: Any suggestions?

Yeah. Provide some details. What's the box used for? Where? Why? No one can provide a really viable response without knowing details.

JOAT You'll never get anywhere if you believe what you "hear". What do you "know"?

- Granny Weatherwax

[Jim]

As other have suggested, using a very good paint which is water tight is the next best thing. You do need to keep water out as much as possible since interior grade plywood does not use waterproof glue. And, unlike marine plywood, the layers are not selected for water tightness. I suspect you need to plan on lots of routine maintenance. Jim

[Ba r r y]

Vinyl siding?

I'm really not kidding...

Barry

[Larry Blanchard]

Do a Google on "Plywood aquarium". No, I'm not kidding.

But if the plywood has already stated to delaminate, you're SOL.

[john]

You could coat with something like West expoxy (thin it and use a roller). You could also just go ahead and fiberlass it like a boat hull, then put on a WHITE gel coat

John

[– Colonel –]

Or (cheaper) just put paint over the polyester resin and fiberglass.

[Lee Gordon]

How about covering the box with (white) plastic laminate like you would use on a kitchen countertop.

Lee

[AAvK]

Ever watch the show on TV "The Big Build"? It's the one in which they build a small sized viking long boat, some of it from fresh cut doug fir (the basic plywood), covering it with at least a thousand years of waterproofing using 'pine tar', available from Jamestown distributers, and thinned with real turpentine. But that's expensive like Spar varnish, still cheaper than a rebuild with marine grade ply.

[AAvK]

It can be searched for, for a better price, "Bickmore Pine Tar".

[fredfighter]

At major home centers you can usually find solid polymer foam insulating panels with the sheet goods. Around here they typically carry pink or blue extruded polystyrene in several thicknesses and often also have styrofoam and polyurethane foam panels.

The polystyene and styrofoam will disolve in some epoxies, and are readily combustible, (you can light them with a match). The polyurethane probably has better solvent resistance and a much higher flashpoint, but may slowly oxidise, becoming crumbly after several years.