System 3 "Epoxy Book" described a method to mix epoxy with insufficient hardener and allow it curing time. This would cause mixture to thicken but not set. When you were ready to apply and let it fully cure you would add the correct proportion of hardener required to get a full cure. I don't think it extends working time but lets you have thicker mix that will cure clear. Didn't find useful ways to use it, I'd rather put more coats on to fill weave. I think you can down load their manual from the S3 website.

: Was putting on a fill coat yesterday, and as usual having a fun time herding
: the epoxy around with a squeegie. As I got towards the end of a batch it
: had just started to kick, and the process and results got much better.
: Like going from Aunt Jemima to honey. Another few minutes and I was on the
: wrong side of the kick. This got me thinking (usually trouble) about
: prepromoting the epoxy for fill coats, but I can't find much info. So...

: Anyone have good/bad experiences to report? Any favorite ratios, wait times,
: etc? Is a prepeg'd mix smooth or 'gloopy?' What does prepromotion do to
: the pot life of the finished mix? I'm using System 3 medium for the
: detail-oriented.

: Thanks.