: I just started my second boat, a North Bay (from kit) yesterday afternoon. I
: coated the panel scarf joints with unthickened MAS exoxy, let it set a bit
: and then went back in with epoxy thickened with a bit of wood flour and
: cab-o-sil.

: The MAS epoxy that came with the kit has the "slow" hardner. Even
: with garage temps in the low 60's, the epoxy seemed to be setting up
: awfully slow even by slow standards (and yes, I was careful to mix it VERY
: thoroughly). On my first boat, I used West Systems epoxy and even with
: cool garage temps, their slow hardner seemed to set up significantly
: faster than the MAS. I think that for bonding purposes at least, I may
: need to order some medium or fast different hardner...

: Comments??

An easy way to deal with differing temperatures is to get a quart of MAS Fast Hardener and an additional pump. Then if the temperature is in the 60's you can blend the fast and slow hardeners to customize your cure time. For example you may want to use three pumps of resin, two pumps of slow and one pump of fast. As long as you use equal pumps of total resin to total hardener you will be ok. If you were to use two pumps of resin, one slow and one fast you would actually have the equivalent of the MAS Medium Hardener.

In our shop we usually use a mix of 25% fast on the hardener side during winter temps in the mid 60's to wet out fiberglass. Be aware that if you exceed 30% fast on the hardener side you could get amine blush. If you can raise the temperature of your project with a small heater or clamp lights to avoid the expense of heating a large workspace.

If you are working in cool temperatures you will want your epoxy to be stored at 70-75 degrees so that it will mix well when you use it and it will have the viscosity that will best wet out your fiberglass. We installed insulation in a cardboard box with a heating pad underneath. We leave the jugs of resin and hardener in this box with the heating pad on low or medium until we use them.