a different exhaust question.

[slapthefunkyfour]

Tonight I'm gonna weld up the exhaust for my 66. I just barely finished the new 350 transplant, and started it for the first time last night. Before I spend 20 minutes breaking in the cam, I figured I better put some mufflers on so I don't piss off my neighbors.

I bought some exhaust pipe from the local master muffler to use. From what I can tell, it is the exact same thing as EMT(electrical metallic tubing). Is there really a difference? I think that EMT is galvanized so I really need to hold my breath if I weld that stuff. I could be wrong.

So my question is: what is the difference between plain old exhaust tubing from master muffler and EMT?

[jarkill]

Check here it might give you what your looking for.

http://66.154.44.164/forum/showthread.php?p=1063557

[slapthefunkyfour]

Originally Posted by jarkill

Check here it might give you what your looking for.

http://66.154.44.164/forum/showthread.php?p=1063557

Thanks for the reply. I know that welding galvanized is dangerous and nasty. It seems as though a bunch of guys in that thread have used it successfully though. I guess a super respirator is in order if I decide to use EMT.

[jarkill]

I have used it in many applications and it welds fine. It is nasty to breath it but the good thing is that it wont kill you it might make you sick for a day or so if you breath large amounts of it though. Just try to grind off the galv in the areas your gonna lay your bead and wear a respirator. Here is the MSDS for it......good luck bud

http://www.atlassupplycorp.com/Conte...galvanized.pdf

[vin63]

Originally Posted by slapthefunkyfour

Tonight I'm gonna weld up the exhaust for my 66. I just barely finished the new 350 transplant, and started it for the first time last night. Before I spend 20 minutes breaking in the cam, I figured I better put some mufflers on so I don't piss off my neighbors.

I bought some exhaust pipe from the local master muffler to use. From what I can tell, it is the exact same thing as EMT(electrical metallic tubing). Is there really a difference? I think that EMT is galvanized so I really need to hold my breath if I weld that stuff. I could be wrong.

So my question is: what is the difference between plain old exhaust tubing from master muffler and EMT?

Are you sure it is EMT and not aluminized steel? Aluminized steel is also a hot-dip process, but with an aluminum-silicon alloy - one of the most common types of steel exhaust tubing. The aluminized steel tubing is relatively easy to work with...the only thing I do is hit the areas I want to weld with an abrasive disc to keep my TIG welds a little cleaner.

[lakeroadster]

Originally Posted by jarkill

I have used it in many applications and it welds fine. It is nasty to breath it but the good thing is that it wont kill you it might make you sick for a day or so if you breath large amounts of it though. Just try to grind off the galv in the areas your gonna lay your bead and wear a respirator. Here is the MSDS for it......good luck bud

http://www.atlassupplycorp.com/Conte...galvanized.pdf

And the respirator needs to be one designed specifically for welding galvanize. A regular old painting respirator won't filter the zinc fumes.

That's why it's better to use an applicable dust respirator and remove the galvanize before you paint. Once welded the galvanize turns into gas fumes which are easily breathed and enter your lungs. Even then the fumes settle inside your helmet and in your workshop. The best method for those of us that don't have fume extraction and the correct safety gear is to not weld on galvanize, period.

When I did my exhaust last month I used the aluminized tubing.... My ex-brother in-law was a welder for a living. Back in the late 70's he welded some galvanized steel.. lost his appetite, said nothing tasted good anymore. They told him to drink milk, and that was supposed to make him feel better. When it was all said and done he was in and out of doctor's offices, lost 20 lbs and missed a months worth of work.

It ain't worth taking chances with your health. Who's lookin' out for ya?

[blackedoutharley]

Aren't you supposed to break in the cam on initial start up?

[Captainfab]

Yes that is very critical, especially with today's oils and a flat tappet cam. As soon as the engine is fired, the 20+ minute cam breakin should start. Hopefully the OP is using a good breakin additive.

Originally Posted by blackedoutharley

Aren't you supposed to break in the cam on initial start up?

['63GENIII]

I'm an electrician by trade and the EMT that we use now is not a hot dip galvanize like we used to use but guaranteed, it DOES flare up just like the old stuff and produce vapors. Might not be enough to cause rigormortise but can easily make you sick nonetheless and welds like crap if you don't clean it well. I too have used it for exhaust because it was cheap, I have the bender and I didn't know better. I bent it up and had an exhaust guy weld it up for me. When I came back, he was ready to kill me for not telling him it was galvanized. I'd just use the aluminized stuff anymore. Is the EMT that much cheaper?

[slapthefunkyfour]

So it turns out that I am now dead. I am posting this from the grave to let everyone know that welding galvanized is very very dangerous.

No, really.

[slapthefunkyfour]

I went to Home Depot, and it turns out they don't even sell conduit bigger than 2 1/4", so I'm just gonna get my pieces from an exhaust shop anyway.

[vin63]

Originally Posted by slapthefunkyfour

I went to Home Depot, and it turns out they don't even sell conduit bigger than 2 1/4", so I'm just gonna get my pieces from an exhaust shop anyway.

Did the tubing you originally got from the muffler shop look like this?


If so, then is should be aluminized steel.

[lakeroadster]

Originally Posted by slapthefunkyfour

So it turns out that I am now dead. I am posting this from the grave to let everyone know that welding galvanized is very very dangerous.

No, really.

Look at this topic like smoking cigarettes. We all know people who smoke and drink everyday and who have lived to be very very old.

But then we also know people who haven't.

It's all what your comfortable with.

Or another way to put it: If someone were to take a revolver and put one bullet in the chamber, spin the chamber, put the barrel to their head and pull the trigger they would have a 5 out of 6 chance nothin' will happen. That's over 80%!

Life... it's all about playin, or not playin, the odds.

[raycow]

I have used EMT because it is the cheapest stuff you can get, and you can find benders for it pretty easily. A flap wheel works quite well for getting the plating off. However, note that it does NOT come in standard fractional ODs, which can be a problem is you are trying to slip-fit normal mufflers onto it. Other than that, I have no complaints.

http://www.home4c.com/conduit.htm

Ray

[bubba327]

As a master electrician I usually have access to EMT on a daily basis.
My exhaust systems are 2" EMT, and my shop has big hydraulic benders.
But you guys are correct- welding on ANY galvanized metal of any kind is dangerous. But we have to do it.
Take precautions!
Go outside with good ventilation.
keep your face out of the fumes
Be quick! Use short quick welds and do not run un-necessary large welds
I will always set a fan up and blow fumes away with prevailing breezes.

[63chevyll]

I have never heard of people running EMT as exhaust, but what ever works i guess.

Over the last 15 years all i have ever used was aluminized pipe.

Its designed for exhaust and it wont look cheezy

as far as bubbas truck, most people dont have access to a 2 inch bender for EMT..

What wall thickness is it anyway?

[raycow]

Originally Posted by 63chevyll

as far as bubbas truck, most people dont have access to a 2 inch bender for EMT..

What wall thickness is it anyway?

Nominal 2", which is actually 2.197" OD, has an .065" wall. I have found tool rental outfits that had conduit benders.

Ray