Seeking Advice on Waterproofing Custom Built Wood Trays

[LFLarry]

I am in the process of making some all wood trays for normal darkroom processing (dev, stop, fix, wash) and want to know the best way to water/chemical proof the trays?

Thanks in advance.

Larry

[willwilson]

I have a set of 30x40 wood trays I built. They see limited use. They are painted with several coats of water based polyurethane. Works well and poly is easy to work with.

If they were more frequently used I would have epoxied them. I use west systems but there are other options too. If super heavy duty, you could add some fiberglass cloth. West systems has lots of info on their website.

[Eric Woodbury]

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.

[MrFujicaman]

Ditto on the truck bed liner. I built my darkroom sink with it 5 years ago and it's never leaked.

[Willie]

Rubber shower pan liner pushed in place and folded over the sides works - also for a full sink.

Sheets of plastic work. Lay it in, fill the tray and empty later and throw it out as it wears.

[lab black]

West and fiberglass. 25 years and my sink hasn't had a single leak.

[Jim Noel]

I built my plywood sink in 1989 using 3 coats of West Systems 2 part epoxy. It still serves me well. No fiberglass.

[John Layton]

Built my sink and large trays with Rakka epoxy (less expensive than West) over birch ply…super smooth, tough as nails, and has been holding up great - with absolutely no signs of liquid infiltration.

[HMG]

OK, I'll bite. Why make the trays out of wood? Odd size?

[Drew Wiley]

It's likely to be more expensive in wood. Have you checked the price of penetrating marine epoxy these days?- which is what you need. And it's nasty to work with. How about marine ply? - an already expensive product up about 400% due to pandemic shortages, unless you already have your own stash. Much simpler just to solvent-weld some ABS sheeting. West is a B-line across town from me. They bought out their competitor Smith Epoxy along the freeway, but still keep that brand going in parallel. We sold more of their epoxy products where I worked than the factory outlet itself. Gosh knows how many wooden darkroom sinks I've told people how to make. But I wouldn't do it myself, and I was in charge of the biggest Festool dealership in the country west of New England - so you can't say I don't know how to make a straight plywood cut! ...and the danged sheer weight of wooden trays. I've made oversize 30X40 acrylic trays, and those are heavy enough. But if that is what you like doing, so be it. Just do it outdoors. Both liquid epoxies and fiberglass resin give off very unhealthy vapors. Avoid skin contact as well.