Hi Tim,

I have seen tongue mufflers that were pinned and JB "Welded" which have held up quite well.

BIG Bear
RNMM/AMM

So -- try it and see what falls off?

     I'm too lazy to try it, but how about an entire muffler molded of the vinyl or rubber compound used to make the DuBro exhaust extensions?

We have one plane flying control line at my field with one of those extensions.  It flaps in the breeze, and makes it sound like the plane is blowing a five minute raspberry.

That would certainly add an interesting dimension to the whole tongue muffler experience.

     The two things that made me curious about it are that the soft material can be sound deadening instead of transmitting, and much more crashworthy than a rigid muffler.  Or combine it with a surgical tubing venturi extension to keep dirt out of both the intake and exhaust when terra firma contact occurs.

Long rough grass gives us the hardest time keeping the nose up where it should be on takeoff and landing.  As for crashes, I saw a friend slice an engine in half on the pavement at VSC.

Thanks Steve.  That's not what's on my mind at the moment, but I may get back to you.

Those markers are small enough that you may not be able to weld 'em.

I tried my silicone caulk idea and made a stretch on bee muffler for a cox .049.  It works OK but looks like a glue turd.  (am I allowed to say that here?)

I used a 7/16 bolt, wrapped a layer of gift wrap tissue paper over it and taped the ends.  I then wrapped a thin strip of the same tissue (ok, about 10 strips stacked up) so I had a rib 1/4 inch wide and the total diameter was 3/4 inch (so it would easily stretch over the engine head)  I then wrapped some of the same gift wrap tissue around a pin till it was 3/16 inch diameter, and pinned it into the buildup ring on the bolt.  I moistened with water to hold everything in place.

Next I applied 100% silicone caulk to the paper form.  I clamped the bolt in a vise and left it.  The caulk surface cures in about an hour, and is actually solid through much of the thickness.  Being wrapped on moist paper helps cure the inside, and also allows for easy release at this point.  Pull the pin, pull the paper out, slide the whole assemblage off the end of the bolt, and unwrap the paper from inside.  I then let it sit for a couple days to finish curing.

I was generous, although if I do this again I am using paper disks and tubes to control the caulk. 

Trim the excess, and pop it on.  It works well...even though it is ugly.   I was concerned about how much heat the caulk was retaining as the engine seems to run hotter than normal, and the muffler became too hot to touch very quickly.  The crankcase seemed to be "normal" temperature but it acted like fuel was boiling in the 8cc bee tank near the end of the run.

I have pictures but the computer isn't cooperating right now.

Phil

Phil -- that's a neat idea.

You can get two-part silicone casting resin, so you don't have to wait a long time for stuff to set up.  It has two interesting properties: 1) it has a super high coefficient of thermal expansion, and 2) if it's confined and heated, it's gonna expand regardless of what's in the way. You could use it to make a better-looking muffler than Phil's (although his looks pretty cool), but it would probably fall off when it got hot.