Epoxy resin has its quirks but the one thing for sure is that it is a messy medium to work with. Get the mixing wrong and you have a sticky mess or a volcano when it sets up too hot. Spill it and it’s tough to clean up. One of my first disasters was when a mold for a big pour broke loose and I had a quart of resin all over the floor. Best thing to do is to let it dry and chip it up.
Learning from my mistakes I now use a couple different methods to contain spills. First is a plastic storage bin that is big enough to hold the entire piece I am working on. Second is a tray which I line with plastic making cleanup a breeze. I also add a piece of 1/2” thick UHMW plastic sheet with bolts in all four corners. Resin does not stick to the UHMW sheet. The bolts allow me to adjust the sheet to level.
So the big takeaway from this is plan for a spill, you will have one at some point. And second, mix the resin throughly, very important. I use clear plastic cup or containers and stir until I no longer see swirls and then I continue stirring for a count of 60, generally totaling three minutes.