Does your heating pad say “can only be installed on Non-conductive surfaces” too? Haha, here goes nothing.
Yes, lol. I would think the main reason for this is if the pad somehow were to short out and an exposed wire touched a conductive surface that an issue may arise from that.
Here’s something that might fit the build a waterbed heater, 120 volt w/adjustable state.
I put 5 gallons of RV anti freeze in the table last week.
Seems like the best solution to me.
You can smell it when you open the shop up.
Keeping the shop heated would help. I use plain water in all my water coolers for my tig welders (because I don’t want the my animals around antifreeze) I keep it between 55 and 60 all winter. Its also better on the welders, plasma cutters and electronic to keep them warm.
My set up is similar. A temp controller with a barbecue coal starter… Keeps the chicken water from freezing as well. Lol
Like your idea as nothing in the water.