Welding Muffler

[Peteohms]

Almost lost my tailpipe. (kitfox 3, 912) The side of the muffler around the tailpipe is cracked and the pipe is barely hanging on. I tried to weld it but guess its stainless. Any ideas where to take it to be welded?

[Geowitz]

You can still weld stainless with regular 70s-6 wire through a mig. I did it for my exhaust and just painted the welds with high temp paint. You can see the black paint on my exhaust joints in the pic near the firewall.

[Peteohms]

Thanks for the reply, but I'm looking more for where to take it to be welded. How to find someone local who can weld this thin stainless. I can just barely weld with oxy/acet.

[Steves142]

Pete, I just repaired one twice for a 912. The first time I tig welded the tail pipe back on the end of the muffler, welded up the cracks and added a support bracket. That lasted about 5 hours. The second time I cut the end of the muffler off, made a new one, welded a tube extension with holes in it on to the inboard side of the tail pipe so it would sit inside a socket on the opposite side of the muffler and tig welded it all back together. So far so good. I guess the tail pipe needs to be supported on both sides of the muffler.

[Peteohms]

Thanks Steve, Could you dive me more detail on what kind of wire you used etc. so I can pass the info along to whom ever does the weld.

[tucsonchris]

I currently have a similar issue with a cracked muffler. Search for "cracked muffler" on the Matronics forums and you will get lots of advice. The consensus is it should best be done by some skilled in Tig and stainless welding. I'm going to start with calling some race/offroad fabrication shops locally.

[n85ae]

I had my IO-240B exhaust rewelded to re-route a pipe that was hitting the
cowl inside. These folks did a super job, and the price and turnaround was
very good.

http://www.awi-ami.com/

Jeff Hays

[SkyPirate]

when welding stainless,..if you have an extra tank of argon,..or a "T" in line from tank to tig head,..you should purge the interior of the pipe being welded or it will crack again,..stuff a wrag around the hose going into the pipe and reduce the outlet with another piece of tubing and another wrag,..it will look like you tig'ed it on the inside as well if done properly,..if you don't do this you get perocity on the interior of the pipe where the heat is ,..the perocity heats up quicker,..making the external weld weaker..

Chase

[mr bill]

An excellent exhaust welding vendor is Dawley Aviation (dawleyaviation.com)in Burlington, Wi. I have used them many times over the years and their work is excellent. The last job I gave them was to weld .012 thick stainless steel. While I was there, they showed me work they had done on someone else's project, where they welded .015 thick aluminum. First rate people and workmanship.

[Steves142]

I think the important thing is supporting the tail pipe on both sides of the muffler. There is a socket welded on the inside, opposite the tail pipe. They used to weld a perforated stainless tube over the tail pipe on the inside. This would extend into the socket on the opposite side giving the pipe support on both ends of the muffler. According to Kitfox they don't use perforated pipe any more they just extend the tail pipe and drill holes in it.