Baron’s Hobbies – Online Hobby Magazine

Tip Of The Day- Make A Muffler Gasket

Posted on March 13, 2009 by aaronredbaron

Exhaust systems on model airplanes and helicopters can be messy. If you don’t go to the trouble of sealing your muffler’s header to the engine, you will likely end up with some sludge seeping out where the two meet, and the dirty stuff gets sprayed all over everything. You can make a gasket out of gasket material, but my preferred method is to make a very thin, one time use gasket out of high temperature silicone.

Don’t Just Slather It On

Although it may be tempting to just put a thin layer on and go for it, the chances of getting some flecks of silicone int your engine are pretty high. It may not hurt much in your engine, but it will foul your glow plug immediatly. The alternative takes a little more time, but produces a clean, thin gasket. All you need is a piece of wax paper, high temp silicone, and your muffler.

First off, clean the mating surface of the muffler well, making sure you get all the oils off. Apply an even bead of silicone to the mating surface of the muffler, and then lay a piece of wax paper over it just large enough to overlap the edges. Puncture the wax paper at the screw holes with an exacto knife, and proceed to mount the muffler on your engine (for the purposes of the pictures, I bolted the muffler to an exhaust extension). You only need to gently snug the bolts until the silicone is being squeezed out. Allow the silicone to cure completely, and then back the bolts out. At this point I usually cut three sides of the wax paper off and trim the silicone around the edges with a sharp exacto blade, because cutting the silicone with the paper makes it easier. Then peel off the wax paper, clean up the fourth side and trim around the inside of the muffler, making sure to clean up an material stuck to the inside. Once its all cleaned up, you are ready to mount the muffler like normal, but now you should have an air tight seal!