Muffler Modfication
 

I have plugged the opening in the rear of a muffler and have drilled a hole near the bottom of the muffler into which I will insert a 1" section of exhaust pipe that was cut off a Slimline sport muffler. This will direct the slime down and away from the airplane. My question is concerning what I should do to secure the pipe in the muffler. It is a nice snug fit, but the pipe will enter the muffler body as far as necessary. In a perfect world, I would find someone who welds aluminum and have him do this, but short of that, what can I use to secure the pipe? Liquid steel, JB Weld, ???????????? What have some of you found works best aluminum to aluminum?

RE: Muffler Modfication
 

Either JB Weld or muffler cement. Epoxy won't hold because of the heat.

You do know you can adjust most mufflers so the exit pipe points in different directions? ;)

RE: Muffler Modfication
 

And a couple of inches of silicone tubing doesn't add much backpressure.....

RE: Muffler Modfication
 

Charlie P., this muffler is on an old Como .50 that only had an opening at the rear of the muffler--no pipe of any kind and no kind of rear section that rotated at all. It was simply a tube with a hole in the rear. What is muffler cement and where can it be purchased? Is this the old automotive stuff that dried like granite?

RE: Muffler Modfication
 

This is the stuff I've used, but not on an r/c plane engine....


http://www.shop.com/+-a-auto+muffler...2-k36-st.shtml

Good luck

RE: Muffler Modfication
 

I'd use JB Weld. The trick is the surfaces must be 100% free of oil or dirt. Most machine shops can weld aluminum, even cheap cast like your muffler is made of.

Dr.1

RE: Muffler Modfication
 

Try drilling a few tiny holes in the tube near the end that will be inside the muff. That way you can push it farther in than just the thickness of the muff material.
JB will work - it is essential to rough up the AL surrounding the hole and around the tube - basically, wherever you want the JB to adhere. Clean with denatured alcohol.
You're going to want a fillet around the seam at least 1/4 inch thick stretching about 1/2 in. up the tube and onto the muff.
It'll work!

RE: Muffler Modfication
 

It's too late for the muffler you've already worked on, but it you have another one have you considered an [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD636&P=M]exhaust deflector[/link]? They may not work for your particular application, but for future reference.

RE: Muffler Modfication
 

I used JB Weld to join the two pieces and it seems very solid. I have not run it yet because I want the stuff to cure completely before I introduce that kind of heat and vibration to it. And yes, I have the silicone exhaust deflectors that slip on the actual exhaust pipe that extends from the muffler and clamps with a wire tie, but this muffler had no pipe to slip it on. That is what I am putting in it now but the pipe that I am using will be directed down and away from the fuselage and slightly rearward so that the deflector may not be necessary.

RE: Muffler Modfication
 

Here are three pictures, I hope. Should be better than 3,000 words.

RE: Muffler Modfication
 

Good idea, good job too