1. Make a table (Excel) of resin, hardener, and finished batch weights and post it near my mixing station for reference.
2. Once I pick a batch size for a given task, I write the resin weight and batch weight on the paper plate that I use to protect my small gram scale from drips, place it on the scale and zero it out with an empty cup (since I cut my cups down from larger used coffee cups, I zero the scale for each cup).
3. Then I don't have to think or remember how many pump shots, or whether I am getting a full pump. Just add the correct amount of resin (can sit in the cup for as long as needed before adding hardener), then top it off with the correct amount of hardener to get the combined weight.
4. Keep a clock or watch hung near my mixing station so that I can make sure I stir long enough (for West System it is 2 min).
On putting jelled resin on glass; been there, done that. Won't ever happen again.
