Straight polyester resin is air inhibited in curing. In other words exposure to air will keep the surface from curing completely. Resin intended for a final coat will usually have wax in it which rises to the surface and keeps the air away.

What you are experiencing may just be this characteristic. At 80-90 degrees, I would think any polyester would cure even with a small amount of catalyst. You could try to get some of the wax additive and painting on another coat of resin to help cure what is there already.

> Season's greetings to all,

> I live in Thailand and know all too well how things operate here (as far
> as getting what you pay for), I was wondering what the possible symptoms
> of low quality polyester resin might be?

> Is it possible that the resin wouldn't harden overnight if it's of
> inferior quality?

> The average temperature is between 80 and 90 degrees F (sorry to all you
> folks suffering out there in the temperate world) so I would think that it
> should set up rather quickly.

> BTW, I mixed it really well (I thought) with a drill and mixer for a few
> minutes at a ratio of 1% catalyst and 1% (of 10%)cobalt promoter. That
> same mixture had worked just fine on other batches.

> Last question: how do you remove an area of soft resin if it doesn't get
> hard? I'm ready to get messy!

> Thanks a lot! Dave