Polyester resin to catalyst ratio is 100:1, or 1% catalyst. This should be adjusted up or down with temperature. Its summer, and hot out there, so you can cut that to .5%.
The best way to get this is to use a triple-beam balance scale and weigh everything. If you are going to do a lot of laminating, invest in one, they are worth it.
Without a scale, the next best method is volume (and this IS why metric is better) Most of the plastic mixing cups you get at the hardware/paint store have the measurements printed on the side, in litres. A litre is 1000 g. You will also need a small measuring cup with cc (cubic centimeters) on the side. These are found at your hardware/paint store, or at the pharmacy.
1 cc of catalyst weighs 1 gram
500 g resin, or 1/2 litre, takes 5 g catalyst, or 5 cc. (3 cc in hot weather)
You can be off on the measurement, and It will only effect the cure time.
One last note: Resin cures by volume and heat. So if you are done and have an inch of resin in the bottom of the cup, DO NOT let it sit and walk away! It will generate enough heat to smoke, and create toxic fumes, possibly a fire! At the very least, ment the plastic cup.
After it solidifies, add water to the top until finished curing, and then you can throw solid material away.
