Edit: Just found this info in a earlier post on this thread:
lso to make a Fisher more stingy with wood; They were designed with a triple door seal that did not use a gasket. The raised area around the edge of the door makes contact with the bottom of the channel on the stove, and the raised edges of the channel contact the flat door creating 3 contact surfaces. They were considered air tight as built. However there is enough air leakage, that many will not hold a fire overnight. By adding a THIN gasket to the channel bottom, an air tight seal is achieved, and a longer burn time is achieved. You will be able to rake the coals around and add wood in the morning, instead of starting a new fire in a warm stove ! They act like a different stove. The gasket material should be the flat type used to install glass in doors. If the round rope type gasket material is used, it can cause problems closing the door. The only problem this can create is when replacing the gasket material. ALL the old cement should be removed from the channel due to making the replacement gasket too thick, adding more cement to the old can cause door closing problems.
That's sort of what I tried to do.