I built a rather sturdy cabinet system to house (among other things) a 6' long ABS plastic convertible (kitchen/darkroom) sink assembly. It's un-reinforced, and I'm trying to get the sink as strong/rigid/problem-free as possible. I've already epoxied birch ply strips to the recesses (ribs) at the bottom of the sink with the hope of strengthening it. The whole thing is vacuum-molded... and the lip is totally hollow. However, this thing needs to support quite a lot of weight, and I don't want to risk having the structure of the lips sag. So I was thinking perhaps I should build up the undersides of the lips more substantially (perhaps with glass and cloth or wood and bondo or something). Any suggestions? Also, how should I seal the edge? Silicone? The counter it's being built into is maple ply/9x layers lacquer.
From contributor J:
I would guess your best bet may be the simplest - build supports under the bottom of the sink, similar to the cradle you would build for a cast iron farmer's sink. That way you won't have to worry about the weight on the rim.
As far as caulk, whenever I've got a problem surface, I use Sikaflex. Just make sure to use gloves and have some acetone around for clean up. The thing I'm most concerned about is your countertop. Photo chemistry will make a mess of that in record time. You might consider p-lam instead of lacquered plywood. Of course, you know the inherent problems of having your darkroom double as a kitchen? Don't forget an exhaust fan that is light baffled.
I suspect the darkroom chemicals (black and white only) will not interact too badly with the lacquer (we're talking about soda-water here) - though most of the processing should occur in drums anyway. Hopefully there won't be too much splashing around. Though perhaps I should have considered an epoxy surface.
Thanks for the Sikaflex tip. Is it colored? I'm just concerned with the sealant being visible.