Hi Pat,

It sounds more like uncured epoxy than blush to me. In my experience blush is more oily like sun tan lotion and has an oily appearance on the boat surface that will smear when you wipe it with your finger it doesn't load up sand paper. If the paper is loading up with a yellow stick material and the boat surface is soft (can dent with your fingernail) it's most likely epoxy. The best thing to do is wait a little longer before you sand. High humidity is most likely the cause if your sure you had a good mix.

Kent