Quantum leap foreward!

[William Whitaker]

What Cyrus said (the second time)...

[John Koehrer]

Seal it with Polyurethane or varnish, a brace along the front or back if it flexes a bit.

[jeroldharter]

I would still treat it with something. Generallynspeaking, untreated plywood is a terrible darkroom material. It is usually covered in sawdust that lingers for years, is impossible to clean, etc. However, it is very useful when treated with something so that it is not dusty and can be cleaned.

Walk on a plywood floor in bright light and watch the plumes of dust rise...

[jk0592]

I have used plywood with West System epoxy to hand build my120 inch long darkroom sink. The only problem is that the stop bath reacts with the epoxy. The epoxy first gets stained like the indicator color of Kodak indicator stop bath, and gets thinned out. Some repolishing/reepoxying will get necessary in the future.

[Greg Blank]

This is a P.O.S plywood. coat it with spar varnish and be done with it.

[Greg Blank]

Even better, baha hahahah!

Realistically speaking, if this is just an old piece of plywood, why not just use it and if it gets too bad, toss it and get a new piece? KISS. Just wipe off any dust/crud and have at it

[patrickjames]

I did the almost exact same thing years ago. Unless you are really sloppy you should just use it. You can put newspaper on it for any little drips.

I would suggest that you figure out exactly how long it needs to be and perhaps cut it down a little. 8' may be a little unwieldy.

[David Karp]

I primed some wood I use for darkroom applications and then sprayed it with appliance epoxy. It has held up well and the painting was a snap.

[Bruce Pottorff]

Prime both sides and then have it coated with spray-on truck bed liner. I did this to my darkroom sink ten years ago and it is good as new.

[John Kasaian]

Spray on truck bed liner sounds interesting! The plywood is stock for subflooring, so it's pretty rigid on it's own and will sit on a tile countertop.