~S~ all

I work with polyester resin for 20 years without any problem. You have probably put to much catalys in your resin.
Polyester will cure from .8% to 5% . With .8% i have in a coolday 45 minutes to work . but a good rule of tumb to mix catalys and resin
are 6 drops of catalys for 30 cc or 1 onzes of resin.[8D]. D`ont mix lots of resin at the same time , to glue former in fuselage try 30 cc batch
this way you can work slowly without rushing anything.

Good luck with your project