oliflyer:

The West Marine resin gives you plenty of working time. The resin will start to set up in the pot before it sets on the work surface. The smaller the pot, or container, you mix the resin in, the faster it will start to set. The reason for this is heat kicks off the resin. It is more condensed in the container than on the work surface, so it kicks off faster. I use the deposible zip lock food containers, not the bags, to mix resin in. If you use the West system, I highly suggest you purchase the pumps, there is one for the hardener and one for the resin. The pumps meter out the proper mixture of resin to hardener everytime. I agree it can become expensive if you are planning to do only one airplane, but chances are that if you try fiberglassing and painting a model, you will never go back to monokote (ultracote) again.