Stationary Engine List

Making Mufflers

| March/April 2002

Stationary Engine

To begin with, another update to the 'Tillie' story. She finally, and with some difficulty, made it into our garden, much to the bemusement of our neighbors, who have been asking which direction we intend to fire our 'cannon.' She has indeed fired, and run for some length of time. On Hew Year's Day, as part of the annual Worldwide Engine Crankup, she ran alongside a selection of smaller English and American engines - despite below-freezing temperatures resulting in a very happy owner!

And so on to the discussion that attracted my attention this month on the ATIS Stationary Engine Mailing List. As ever, the following comments reflect a variety of opinions that surfaced during this discussion.

I'm thinking about building my own muffler for my Galloway. My plan is to use a NPT flange. Has anyone built one using this idea? What goes inside the muffler, i.e., baffles? I haven't figured out the 'top dome' part yet, but possibly someone out there can help? They're a little pricey and it would be fun to build my own.

For a domed top, why not take a piece of flat plate, heat it up cherry red, and hammer it to a domed shape with a flat rim? Bolt it to your flange with a flat washer or two as a spacer? You might also be able to find some assorted cast iron bits (floor trap, etc.,) at a plumbing supply house that would have a domed shape. You'd probably need to weld some bits to it, but it would be a start. Have fun, get creative. And you don't need anything inside - the spacing between the two halves controls the amount of bark.

Someone mentioned using the bottom of a fire extinguisher for the dome, they're usually available at extinguisher service centers as rejects.

That was me! I attempted to fashion an authentic-looking replacement for the muffler on my 10 HP International M. As for using old fire extinguishers, the old soda acid-type water extinguishers are generally a canister of thin brass, and even the more modern water-stored pressure types are fairly thin steel. I used an old CO2 extinguisher for my dome and found it to be of surprisingly heavy gauge metal. I'd recommend using the CO2 extinguishers because they are designed to hold a fair amount of pressure.