Welding exhaust system?

[njohnson]

Hi,

My brother has a 1997 Civic, and around five years ago, he took it to a muffler shop for some work on the exhaust system. They replaced most of it, along with the muffler. They might have used a cheap one because it rusted through already. My brother bought a muffler from Oreilly's and I put it on for him. I used a 1 3/4 inch connector on the muffler pipe to hook it up to the old exhaust piping. I used exhaust clamps to secure it. The muffler shop had welded the exhaust pipe in certain spots. I was thinking about welding the 1 3/4 connector.

My question is, what kind of welder is used on a exhaust system? Our dad has a stick welder I can use, but, I was wondering, is there any chance I could zap something on the car by welding the exhaust? I have used the welder on some of our farm equipment, but never on a car. Could I fry or zap something by welding the exhaust?

Thanks,

 

[eljefino]

I do it with a stick welder all the time. Biggest hazard is blowing through the metal. I'd practice on some scrap. Go only with about 60 amps.

 

[tomcat27]

more commonly done with a mig. it's advisable to disconnect the battery to prevent frying the electronics - although nobody ever does.
The factory exhaust was stainless steel. the replacement parts were likely "aluminized steel" which has a life span of 2-7 years.

 

[njohnson]

Originally Posted By: eljefino
I do it with a stick welder all the time. Biggest hazard is blowing through the metal. I'd practice on some scrap. Go only with about 60 amps.


Thanks! I will practice on scrap first. And make sure I turn it down to 60 amps.

 

[Rand]

In the ohio salt belt those usually last 2-4 years max.

If you use a good clamp you wont need to weld it.

Its somewhat hard to stick weld that thin a material and continuous around the pipe.

Not for a pro welder or someone with the right tool but I wouldn't attempt it.

 

[njohnson]

Originally Posted By: tomcat27
more commonly done with a mig. it's advisable to disconnect the battery to prevent frying the electronics - although nobody ever does.
The factory exhaust was stainless steel. the replacement parts were likely "aluminized steel" which has a life span of 2-7 years.


That's what I am concerned about, frying the electronics. So, if I disconnect the battery, I won't fry anything?

 

[Chris142]

Shop behind us uses a rod and torch.

 

[spasm3]

Originally Posted By: eljefino
I do it with a stick welder all the time. Biggest hazard is blowing through the metal. I'd practice on some scrap. Go only with about 60 amps.


I've used mig, takes longer. Exhaust is probably the one place you can get away with a slightly cold weld vs burning through.

 

[supton]

Originally Posted By: njohnson
Originally Posted By: tomcat27
more commonly done with a mig. it's advisable to disconnect the battery to prevent frying the electronics - although nobody ever does.
The factory exhaust was stainless steel. the replacement parts were likely "aluminized steel" which has a life span of 2-7 years.


That's what I am concerned about, frying the electronics. So, if I disconnect the battery, I won't fry anything?


Technically everything else is still in the car. If anything I'd leave the battery connected--it can sink large amounts of current as well as deliver. If it were to happen, that is; damage is more apt to come from induced currents, being too close to other wires, etc.

I don't think battery connected/not connected is going to prevent anything.

 

[DuckRyder]

Should be a bolt on muffler unless they did a total hack job on it...

A Bosal, Ansa or Walker stock replacement from the cat back should be less than 200.00 aluminized or ~300.00 in stainless.

 

[Johnny2Bad]

Unless the exhaust was Stainless Steel, I wouldn't bother to weld it. Clamps have worked fine for 100 years, they should work well enough for this car.

 

[Doog]

Originally Posted By: Johnny2Bad
Unless the exhaust was Stainless Steel, I wouldn't bother to weld it. Clamps have worked fine for 100 years, they should work well enough for this car.


+1 this ^^^

 

[Merkava_4]

Originally Posted By: njohnson
My question is, what kind of welder is used on a exhaust system?


They usually use MIG with a small diameter wire that doesn't produce too much heat. Even then, they gotta be moving pretty fast or they'll burn through the thin steel.

 

[Virtus_Probi]

Originally Posted By: supton


Technically everything else is still in the car. If anything I'd leave the battery connected--it can sink large amounts of current as well as deliver. If it were to happen, that is; damage is more apt to come from induced currents, being too close to other wires, etc.

I don't think battery connected/not connected is going to prevent anything.


This would be my feeling, too, you can think of the battery as a giant filter cap that can suck up some transients.

 

[Trav]

If all you have is stick then don't bother just clamp it, stick isn't a very good option for thin wall tubing even on low settings. You can tack braze it in place to prevent movement. Mig with a swan neck is what I use but not on the muffler, there it gets a clamp.
On modern cars I always disconnect the battery when welding, the old cars didn't seem to be effected but back in the day I saw a new 84 Vette ecm smoked after someone welded cat eliminator pipes in. That was enough for me to pay attention.

 

[NibbanaBanana]

If you don't NEED to weld it, then don't weld it. Stick welding is difficult on thin metal and if you burn a hole in it, it's going to be an SOB to repair the hole. MIG or torch is the way to go for exhaust.

I replaced Geo Metro exhausts on two different cars every two years for over ten years each. They just rotted up in the salt. My DD now is a 10 year old Chevy Aveo with 207K miles and still has the original exhaust. Go figure.

 

[4WD]

+1 ... Same here - one man show muffler shop - he has done brazing on hundreds of joints through the years.

 

[MarkM66]

Originally Posted By: NibbanaBanana
If you don't NEED to weld it, then don't weld it. Stick welding is difficult on thin metal and if you burn a hole in it, it's going to be an SOB to repair the hole. MIG or torch is the way to go for exhaust.

I replaced Geo Metro exhausts on two different cars every two years for over ten years each. They just rotted up in the salt. My DD now is a 10 year old Chevy Aveo with 207K miles and still has the original exhaust. Go figure.


I believe at some point manufactures switched to stainless, in order for the system to make it through the catalytic converter warranty period. That may be the case with your two vehicles.

I have an '01 Civic with 310k miles and all factory exhaust, even the muffler is original.

 

[supton]

Originally Posted By: MarkM66
I have an '01 Civic with 310k miles and all factory exhaust, even the muffler is original.


Lucky you. Our 2001 Civic had an mostly new exhaust by 175k; we traded it in 2011 (at said 175k). I forget now, but first the exhaust manifold (plus integral cat) like a year before muffler and tailpipe (which was like a year or two before trading).

But I think road salt has a lot to do with that...

 

[i_hate_autofraud]

If you weld, you'll want to prep and wire brush or grind to clean metal or you'll have messy welds.

Be sure to grind the spot where the welder ground clamp goes on the pipe, so all weld current goes straight back to the welder.

Also, you might want to unplug all the O2 sensors on the exhaust pipes, they're wired straight into the computer and electrically connected to the pipes!! - not isolated or 'floating' - you can blow the computer if you're unlucky.

It's happened before !!