I'm considering making a custom fibreglass darkroom sink - actual sinky bit at the left and a big long ribbed bench/swill wet area that I can place trays or a Jobo on and just tip them over when I'm done. Does anyone have any information on whether any of the standard resins are susceptible to any photo chemicals? Epoxy is nearly everything-proof but it sucks to work with so I'd like to use the polyester resin if possible. I know you can get special "chemical resistant" polyester resins too - does anyone know if there is a common type in particular that I should use for a darkroom sink? I found this table that seems to show polyester as resistant to most stuff at 15C but resistant to not much more than water (no thiosulphate!) at 65C. What worries me is what will happen when I dump 37C bleach or fix from a colour process and maybe spill a few drops or even forget to put a container under the dump pipe. And of course there will be dilute chems coming out after each wash.