Mabel

If you happen to have 10' or higher ceilings in your shop the ideal heater is a tube heater available from most hvac suppliers, including Grainger and even Mcmasters. Propane or Natural gas , they create low intensity infrared radiant heat and heat your concrete, tools, benches, everything in the room, not the air. The air temp will actually be lower than your project, so you will be more comfortable and expoxy wets out unbelievable. It is very easy to install, [just hangs from ceiling with a reflective hood over a 3 " steel tube and small burner at one end] uses outside air for combustion and exhausts outside, and is completely sealed so its ok in flammable environment, and because it heats the floor not the air, when you open the door or ventilate fresh air, the room temp remains constant. This is the heater of choice for industrial shops where doors are opened & closed [like an auto shop or wharehouse] All this for about $1000.