Hello I am 15 and wanting to build a fire place where the heat, heats pipes, and forced air goes thru them. (Very good heater) to heat my shop. I want to make a damper for the fireplace to let the fire be hotter or cooler. And I am having trouble thinking about how to make it, the fireplace will be steel. I am aware that you can buy a barrel stove kit that comes with a damper piece but do not want to spend a lot of money. Does anyone have any ideas? Thanks