welding the top part of exhaust pipes

[eljefino]

How are the compentent ones doing it?

I'm replacing a flexpipe in my project saturn; got a universal one that's just the flex part and not the whole downpipe/ cat/ whatever. Sawzalled the old out, slipped the new in. So far so good.

There's floor pan about 1.5 inches above the top of the junction, so I can't get it from above pointing down. I "zipped" up the side on both sides and just kinda shot sparks across the top which "bounced" as much as if not more than they penetrated. Well, I have a pinhole leak up there.

I have the HF flux wire 110 volt welder, but don't know if they make right angle tips that fit it, or if those are even "a thing".

I have a Lincoln 220V stick welder, and could bend sticks, I guess, so I'd have a 3/4" "fingernail" I can point down. Bending sticks flakes off the flux, so I only get one good shot.

I can get one of those 2" wide stainless clamps for exhaust butt connections, but it would look inelegant and bug me.

I don't want to unhang the exhaust; the manifold has a cat in it and the manifold fasteners rust like crazy from the heat.

I can stuff muffler putty up top where noone can see it anyway. I should have pre-stuffed the putty before assembly, in hindsight.

 

[Warstud]

If all else fails you could make an access hole thru the bottom and weld the top portion of pipe from the inside.

 

[JC1]

They are a pain to weld in place like that. I removed that section in a 98 Sienna and welded it off the van. Maybe a shop would weld the top section for $20-30.

 

[Bluestream]

I always take the pipe off the manifold and tig weld them, its the only way to get clear access

 

[NHGUY]

How about advancing 2-3" of wire before striking the weld?

 

[Trav]

If its tight like that i usually gas weld it (not brazing), quick and easy job. If you find a pro welder he probably has a TIG micro torch.

 

[eljefino]

Originally Posted By: NHGUY
How about advancing 2-3" of wire before striking the weld?


It jumps around more and when the side of the wire brushes the pipe it knocks itself off there and I have these rusty cat's whiskers stuck to the pipe too.

I think the bent rod is my next step.

 

[Black_Thunder]

if all else fails you can weld 1/2 to 3/4 of the way around and then buy a band clamp and put it around the pipe/weld to make a good seal


edit i see in the original post you've already thought of that I had an issue with a pipe that the clamp style clamp didn't hold the pipe well enough and it eventually slide out of the pipe, i was able to get back in but not enough to clamp it again so i welded it half way around and used a band clamp like i said above and it's held up just fine. being that its under the vehicle and you can't see it, it never really bothered me i guess.

 

[eljefino]

Yeah I need to get it state inspected and if there's hokey looking stuff under there (like band clamps) they might get pickier about completely unrelated things.

 

[Chris142]

Muffler shops here use gas and oxyacetelyne and a bent welding rod

 

[Bluestream]

Originally Posted By: Chris142
Muffler shops here use gas and oxyacetelyne and a bent welding rod


They braz stainless alloy?

 

[eljefino]

I got it, thanks all.

Wound up chopping a 10" rod into 4x 2.5" pieces that fit my clamp at a 90 degree angle. At least welding up top the puddle sticks around and doesn't drip away before it cools.

I first tried using a brake tubing bender to put a gentle bend in a rod, but all the flux flaked off and it was useless. I see why they use gas.

 

[Bluestream]

Creative solution..Good to have it all done

 

[zzyzzx]

Pics of the weld please. I am not convinced that the cheap 120V HF welder is an appropriate tool for exhaust welding.

 

[spasm3]

Originally Posted By: zzyzzx
Pics of the weld please. I am not convinced that the cheap 120V HF welder is an appropriate tool for exhaust welding.


I think he used the lincoln with cut rods.

 

[eljefino]

Don't need pics, it's ugly!

 

[zzyzzx]

Originally Posted By: spasm3
Originally Posted By: zzyzzx
Pics of the weld please. I am not convinced that the cheap 120V HF welder is an appropriate tool for exhaust welding.


I think he used the lincoln with cut rods.


I was thinking that they used the HF welder for most of it, and the Lincoln for the top part.

 

[spasm3]

Originally Posted By: zzyzzx
Originally Posted By: spasm3
Originally Posted By: zzyzzx
Pics of the weld please. I am not convinced that the cheap 120V HF welder is an appropriate tool for exhaust welding.


I think he used the lincoln with cut rods.


I was thinking that they used the HF welder for most of it, and the Lincoln for the top part.


Oh i see what you mean.

I know nothing of the harbor freight welder. I do have a lincoln 3200HD that runs on 110 and will easily weld exhaust.

 

[eljefino]

Yup I started with the HF and touched up with the stick.

 

[zzyzzx]

Originally Posted By: eljefino
Yup I started with the HF and touched up with the stick.


That explains why the weld was ugly. I don't know if I could use my HF welder to do that (I think I have the same cheap wire feed welder). Perhaps if I ever try to I should heat the area first.