I would use anything but polyester resin. I used it quite a bit when I was in the Air Force and became quite sensitive to the odor. A good friend in the same career field repaired corvette bodies as a part time gig using polyester. It killed him. If you do use it, ventilation is key as well as masks and gloves. Polyester resin uses methyl ethyl ketone peroxide to start the curing process and either benzoyl peroxide or cobalt napthanate to accelerate the cure. Most commercial resins come with the accelerator already mixed in. Generally, it is the cobalt napthanate which gives the resin it's pinkish hue.If you mix it too hot, it becomes quite brittle and week. The left over resin on the cup can even become a fire hazard and toss splatter all over the shop. Epoxy resin is much stronger and less toxic. Take the time to clean everything, be fanatic about mixing proportions and thoroughly mix the 2 parts before application