I use a thermometer as a guide to prevent having to readjust the Rheostat. I noticed that it's off considerably, not a ton, but a notch and a half sometimes on my Lyman big dipper. It's not the best and I leave the adjustment alone by just unplugging the unit. So for me it's mandatory for now.Yeah I recommend a thermometer for new casters, it can show them a lot about what's really going on. Is it mandatory? No but then neither is a an electric pot but it sure makes things easier.
this is true.... I read from LASC, that if a sprue plate, on a aluminim mould, if not pre heated correctly, (plate side down on a burner or pot), can act as a "chiller". Iron/steel moulds, this is no big deal since both the mould blocks and the sprue plate have similar thermal conductivities and heat up at the same rateBiggest is getting the new guys to understand that mould temp is related more to casting tempo than it is melt temp. Increasing pot temp won't eliminate cold mould wrinkles but casting faster will.
I could go along along those lines, with a generous puddle. I found it hard to do on a single and double cavity, due to not joining others as on my 6 cavity Lee. I wonder if thicker plates would work better than original thinner plates in regards to cooling faster. Don't know if my homemade plate of cold rolled flat bar is as good as the RCBS plates I got recently.As for the sprue plate, it doesn't have the mass the blocks do and will cool faster than the blocks. Also, it spends a good deal of time sticking out in the air while dumping the bullets. This is why I recommend a generous sprue puddle to keep the plate up to temp.