catalyst for a cooler overcast day?

[craigd]

hi
can somebody tell me if normal polyester resin used with hardner is affected by uv rays like solarez is?
basically, its a crap day with crap surf and i wanna do a repair, pretty major one. normally on a sunny summery day i mix at 1% but what about a cooler overcast day?

[Simple Ben]

You have probably already done it but it is the temperature that counts not the UV rays. In winter just add a little more than usual. It is hard to say what kind of percentage, you can put more if its only thin but the thicker, deeper the repair is then you don't want it going off too fast as the heat can't escape and it will crack. It is more a trial and error thing until you get the hang of it.