I take a little different approach. I use the gasket with Permatex Ultra Copper Gasket Maker on both sides. If the muffler bolt heads are not recessed, I drill holes in the bolt heads perpendicular to the bolt shafts. I run piano wire threw the holes. I bend the ends of the piano together and solder them together. I have done this on all my gas engines, Q35,DLE 20,30,35,55, G23,26,62. After hundreds of flights, I have yet to have a loose muffler.