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help welding exhaust

13K views 15 replies 6 participants last post by  scrot 
#1 ·
I am a very amateur welder I have only welded 3xs an if I knew what I was Doing it would be less please explain/teach me how to make a strong weld on roughly 1/8" thick exhaust pipe 2 and 3/4 around. My back can't take crawling under the car many more times
 
#4 ·
Need a lot more info here, what kind of welding are you talking about? More importantly what kind of exhaust pipe are you talking about? I seriously doubt it is 1/8" thick, probably a lot thinner than that, so it should easily weld with Acetylene or MIG/flux core but stick welding might be a bit difficult. This pipe could also be stainless (yes it may be somewhat rusty but still stainless) and if so forget welding with a torch, stainless pipe can be torch welded using a flux for the purpose but it is not practical on exhaust pipe.

EDIT
You posted while I was typing and I can see what your welder is now.

That little AC welder can certainly do it but it is going to be difficult, very difficult for a novice, can you possibly get access to a MIG or flux core welder?
 
#5 ·
more info

All I have access to(own) is 115V 20A in Hobart stick welder I can adjust out put and my rods are 1/4" thick. you are right existing exhaust is no more then 1/16" thick definitely not stainless (it is a hyundai ) new pipe is a little thicker but no more then 1/16" thick. I have no choice but to make this work,
no extraq cash to pay someone. what sucks is I just receivedthe new clutch for it, never did that before and I,m not at all worried.
thanks for your time
 
#6 ·
1/4" rod? :confused: I am not sure what size rod you actually have but that little welder would hardly get a 1/4" rod warm never mind welding with it, a 1/16" rod maybe in something like a 6013 or 7014 should work fine. Tell us a little more about what is/is not working when you try to weld this pipe, is it burning through? The rod sticking? The pipe is just not staying together?


Don't bet on that pipe not being stainless, if it is the factory pipe it almost certainly will be, from the manifold back to the catalytic converter anyway. Stainless exhaust pipe is not bright and shiny and will appear brown and slightly rusty much like carbon steel pipe but it is a bugger to weld sometimes. Although a stainless rod such as a 308 would be best for stainless pipe a regular 6013 or 7014 will weld it fairly good and should hold that pipe with no problem.
 
#9 ·
water wizard said:
It is a 115V 20A in stick welder it is made by Hobart(wal-mart). Pipe broke right after resonator so I removed resonator and have straight piece and adapter to put in place of resonator. was told it won't effect emmissions. original pipe is 1 3/4 od

I welded my exhaust with a stick welder. I found that either 7018, or 7014 rod works best, get some reall thin rod and turn the power down. Get it spotted reall good under the vehicle. When you go to finish weld it, turn the heat up a bit, and work SLOW. I found that spot welding around the whole pipe works best. Keep another peice of rod in your other hand, if you can weld one handed, and slip it into the heat if you burn a small hole.

most people say just go get a mig, but ive welded a LOT of exhaust with a stick. good luck!
 
#10 ·
water wizard said:
All I have access to(own) is 115V 20A in Hobart stick welder I can adjust out put and my rods are 1/4" thick. you are right existing exhaust is no more then 1/16" thick definitely not stainless (it is a hyundai ) new pipe is a little thicker but no more then 1/16" thick. I have no choice but to make this work,
no extraq cash to pay someone. what sucks is I just receivedthe new clutch for it, never did that before and I,m not at all worried.
thanks for your time

if your a novice welder, try reverse polarity (ground being the positive, and the stick being negative) it helps A LOT with learning to weld with a stick, without the stick wanting to...well stick lol, to the material too easily.
 
#11 ·
BigRoy1978 said:
try reverse polarity (ground being the positive, and the stick being negative)


First that is an AC welder he has so polarity is not an issue and it makes no difference which lead he uses for ground and second you have that backwards,

Reverse polarity is electrode positive-ground negative

Straight polarity is electrode negative-ground positive
 
#12 ·
oldred said:
First that is an AC welder he has so polarity is not an issue and it makes no difference which lead he uses for ground and second you have that backwards,

Reverse polarity is electrode positive-ground negative

Straight polarity is electrode negative-ground positive
forgot about AC lol, my bad! Its been a while since i used my stick welder, i got a snap on wire welder super cheap, so its my current weapon of choice. Thanks for the correction!
 
#13 ·
I think it must be just some kind of natural tendency to want to think if the electrode is positive then changing it to negative would be reversing the polarity, reverse and negative seems to go together maybe? In any case it is a very common error but it makes a bit more sense when the actual current flow direction is considered. Since electrical current flows from negative to positive then in the straight polarity configuration, electrode negative and the ground lead positive, the current is flowing from the electrode to ground. Switching that to reverse polarity with the electrode positive and ground lead negative means the current would then be flowing from the ground to the welding rod.
 
#14 ·
oldred said:
I think it must be just some kind of natural tendency to want to think if the electrode is positive then changing it to negative would be reversing the polarity, reverse and negative seems to go together maybe? In any case it is a very common error but it makes a bit more sense when the actual current flow direction is considered. Since electrical current flows from negative to positive then in the straight polarity configuration, electrode negative and the ground lead positive, the current is flowing from the electrode to ground. Switching that to reverse polarity with the electrode positive and ground lead negative means the current would then be flowing from the ground to the welding rod.

yeah i see. thats what i ment, ive always had better luck with it being reverse polarity when welding with lower power.
 
#15 ·
I had to use a stick welder at work years ago since that was all we had (Experimental Metallurgy Field :D ) . It worked great for anything around 1/4" or thicker. Welding less then that was really tricky. I agree with using a thin stick and turn the amps down as much as you can but still get a good arc burning. And then just spot it and work your way around. Let it cool down in between so you dont push the rod thru the pipe all the time!
Maybe you can slot the pipe a bit and slide it on the existing one. That way you have some guide and dont need to clamp it together somehow.

A MIG or TIG welder would really be much easier. But you can make it work with what you have. Do some test welds on similar material on a bench to get the welder set up and get a good feeling on how to do it until you crawl back under the car....maybe easier! :D

Good Luck

Tomi
 
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