In 1993 I stopped using coal. I use only propane in my shop. I do a lot of variety in my shop, I now have 2 basic forges, one for smaller, one for larger stuff. The first gas forge I used for about 7 years, I stopped using as it was the largest least efficient. The smaller 2 burner version I have been using for about 8 years now, almost every day. It uses about 1/2 a gallon of propane per hour and I do a lot of forge welding as well as just basic forging with it. I do use blowers with these and prefer the blown forge over naturally aspirated. I use barbecue regulators (1/2 pound of pressure.) You can see more of the variety of work I produce and the forges I use in the photos posted at forgemagic:
Blacksmiths Gallery'