Muffler welding - diesel

[Steved]

Hi there.

The rear of my muffler blew out and I need to make a crude repair in the next day or so.

Can you safely weld on a muffler that has been used or is there a possibility of unspent fuel being inside of the muffler? (Diesel fuel muffler)

I would hate to strike an arc only to have the muffler blow up on me.

It will be a poor weld as there is corrosion present and I am not sure what I have for a base material.

Thanks for your responses.

[Teeps]

well, there is a reason armored treasury cars use deisel fuel :-)
It's not going to blow up in your face, but little test fire never hurts as long as you keep your distance

Seriously though, I've welded under cars on exhaust systems many a time, I just don't do it while the car is running, or anytime soon after.

The if there was fuel in there, it should have evaporated long ago.
Unless it was been running in the last day or so.

It's not going to be fun welding, try to sand it down as much as possible first.

That's why I'm putting stainless on mine!!!

[dyn88]

teeps is right odds of the muffler having any residual fuel init is low. try using a loose wire brush on a grinder to remove any galvanize or corosion.

[Sberry]

I welded on lots of mufflers, diesel ones too. Never had a problem.

[Manny]

We weld and cut on diesel exhausts daily, very seldom had any issue whatsoever. The only problem you might have would be if you had a bad injector and dumped raw fuel into the muffler. We had this problem once, guy had an injector tip failure, knew he had a problem but drove it another two miles before shutting down to save money on getting towed in. This loaded the exhaust with raw fuel, a little detail he neglected to share with us when it was brought in for repairs. After replacing the failed injector, customer wanted us to run the unit on our dyno to check power. When the exhaust heated up it started a fire inside the exhaust that had the pipes glowing cherry red and shooting flames. No explosion or anything, but it did melt the corners of the sleeper, ruin the chrome exhaust and scorch the paint, over $6000.00 to repairs.....

Manny

[fun4now]

Manny

over $6000.00 to repairs

ummmm i dont think he saved that much by not towing




.

[cleaver]

Hi,

I will be welding under a car in the future cuz I am planning on making an new exhaust system for my car. I was curious as to what are the safety steps needed? I mean of course turn off the car, but do I need to disconnet the battery? I also heard that its good to clamp the ground as near as the weld to prevent the electric circuit to travel all over the car? Correct me if I am wrong cuz I am new to this and have never done it yet..

thanks,
cleaver

[fun4now]

cleaver

yes on bolth disconect the battery and clamp as close as possible

[sparky123]

take your truck to the car wash and give it a good washing on the underside. this will get rid of alot of the road grime and other oils and stuff and make it a little safer. if you can take the muffler off and do the repair on the bench so you can do a good job and make it last. then weld it back on.