Seeking Advice on Waterproofing Custom Built Wood Trays

[Greg Y]

I haven't built trays, but i've had two darkrooms with sinks i built out of plywood & had lined with "Duradek".... (waterproof vinyl deck covering). A couple of days of good ventilation & the smell from the contact adhesive was gone

[xkaes]

Any boating/marine/sailing shop will have a variety of waterproof paints. The epoxy paints are not just waterproof, they are chemical resistant.

[Drew Wiley]

Greg - vinyl deck coatings are pretty short-lived in terms of expansion-contraction survivability, are apt to have some texture, making them hard to clean, stain like heck, and can't tolerate any kind of hot solvent like acetone. Can't recommend them. But someone with industrial roofing skills could heat-weld a true hypalon rubber liner inside a sink. Liquid hypalon is so nasty to breathe that it got banned in the US long ago; I used to sell that for lining industrial plating vats. Penetrating marine or structural epoxies are really the best simple solution on plywood, as long as one is careful health-wise during the application and drying phase. But unlike paints, they cure rather quickly.

If I were still young and ambitious, it might be fun to create a custom laminate waterproof ply using a big vacuum press. I sold a number of really nice German vac presses to cabinet shops just before I retired (no relation to photo drymount presses); not a toy I personally need - too expensive. But all kinds of possibilities with those, even in-house stainless laminates that can be sized down on a panel saw with the right blade, which would of course would itself cost more than a whole set of big prefab plastic darkroom trays - but what the heck. If one has the itch to make things themselves, why not?

[domaz]

I've used the West. It's very good. I've heard good things about having them sprayed with truck bed liner stuff. Many years ago when I had no money, my friend and I made a cardboard sink and covered it in fiberglass resin. Lasted 7 years and then I moved.

Making a sink out of cardboard sounds like an amazing way to save time and money building a darkroom sink. Especially if you don't need it to be permanent. I know the "proper" solution to these things is expensive Marine Epoxy but who wants to deal with the price and smell of that stuff.

[willwilson]

Mine are not really that heavy. Definitely big and bulky though. 1x4 pine frame and 1/4 plwood bottoms. All butt joints with screws, wood glue, paintable caulk, and several coats of poly. They are at least 10 years old and still going strong.

Not my prettiest work, lol.

[Tom Monego]

I built a sink in the in my former house, I used 1x8 pine and exterior plywood covered it with marine epoxy, 3 coats if I remember, I had it fully plumbed. It was still good when I moved out of that house 20 years later. I had to saw it in half to get it out of the room.

[xkaes]

I had to saw it in half to get it out of the room.

I made the same mistake -- making the sink INSIDE the darkroom. Of course, at the time, I never entertained the thought that I might move some day.

I still miss the three feet I had to chop off!!!