I built a darkroom sink for the University of Utah in 1989. It was fiberglass over wood. 6 in. deep 36 in wide and 32 feet long. We did the resin in a single pour. With all the windows open the smell seemed to attract insects. They would fly low over the sink pass out and drop into the wet resin. we must of had 6 or 7 flys and numerous mosquitos and other bugs in the mix. Maybe they just love the darkroom like us.