XJet

Usually, when I want to lay up something with two layers of cloth, I apply the first layer with resin and wait until it gets tacky before I apply the second sheet of cloth and more resin.

Now I'm going to be working on a layup where my time on the job will be somewhat limited and at odd intervals -- so I won't be a round when the first layer starts to gell.

Should I try to lay down both layers of cloth in one sitting or should I allow the whole thing to cure, sand it and then lay up the second?

This is glass cloth and expoxy (West System) over polystyrene.

Mike James

Short answer... Either method will work. (By the way, I mostly use West Systems too.)

For me, it's the size and shape of the layup that determines that decision. If it's something relatively flat, there's no reason to wait. Go ahead and do both layers at once. If you think the epoxy will cure too fast, simply use the "Extra Slow" West Systems hardener. Obviously, you really don't want the epoxy kicking off in the middle of your procedure.

If the shape is more complex, and adding the second layer increases the risk that you'll pull the cloth away from the surface by trying to do both at once, then you can, as you described, wait until it's cured, lightly scuff it, and then add the other layer.