Author Topic: welding exhaust  (Read 602 times)

Offline john h

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welding exhaust
« on: March 17, 2020 - 08:47:38 pm »
All
I needed a budget exhaust system to replace my old one.  I purchased 1 of those Jegs kits for my 73 Cuda. It's the aluminized mandrel bent 2.5" kit with lap splices  It fits pretty well but I'm having trouble getting it to seal up even when using band clamps.  The only welder I have has flux core wire. I'm also not a welder but was planning on practicing on the exhaust pipe I cut out.  I'm wondering if it's ok to use flux core wire or is it best to mock it up and take it to the pros for welding? 

Thanks for you opinions.
John
John
73 Cuda
360 Crate motor
FiTech Fuel injection
727 Trans (wishing it had Over Drive)




Offline jimynick

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Re: welding exhaust
« Reply #1 on: March 17, 2020 - 10:27:32 pm »
Firstly, there's something we don't know about this clamp issue. Band clamps are not the answer unless you cut slots in the female pipe that don't go as far as the end of the joint connection and allow the then fingers to compress and grab. The time honoured round stock 3/8" clamps should work, sometimes you have to tighten the bejeezus out of them and it's not unknown to snap the odd one off when tightening. As for the flux core mig stuff, make sure you grind/file/sand the aluminum coating off before trying to weld them, otherwise the spatter and $hitty weld will not make you happy. Good luck  :cheers:

Offline 70chall440

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Re: welding exhaust
« Reply #2 on: March 18, 2020 - 01:25:17 pm »
I've welded a lot of exhaust aluminized, stainless steel, mild steel, etc. With the aluminized stuff, you need to grind off the outer layer and then weld it normally. A "pro tip" is to only grind where you want to weld. Do not try and weld it in one pass; weld like 1/2" or 1" at a time. It doesnt warp or anything it will just help keep from burning through.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline john h

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Re: welding exhaust
« Reply #3 on: March 24, 2020 - 02:54:18 pm »
I've welded a lot of exhaust aluminized, stainless steel, mild steel, etc. With the aluminized stuff, you need to grind off the outer layer and then weld it normally. A "pro tip" is to only grind where you want to weld. Do not try and weld it in one pass; weld like 1/2" or 1" at a time. It doesnt warp or anything it will just help keep from burning through.
thanks for the input.  I'm still planning on using the Flux core wire but practice on the old system.  I have cut some pieces off and cleaned them up.  I will practice butt weld first.  I also picked up a short piece of new pipe that will lap splice that I can practice on before I get into my new exhaust pipes.  I also ditched the old passive helmet for a low budget auto darkening.  One of my issues with welding is finding the piece to be welded.   
John
73 Cuda
360 Crate motor
FiTech Fuel injection
727 Trans (wishing it had Over Drive)

Offline 70chall440

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Re: welding exhaust
« Reply #4 on: March 24, 2020 - 08:26:19 pm »
I am not going to say it cannot be done with flux core because it can, however you tend to get a lot more pin holes when using it because unless you are pushing forward in one continuous pass, you tend to get contamination in the weld which makes it porous which then is a hole. To use flux core, you really need to grind off each weld to ensure you are into metal and there are no contaminates.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline john h

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Re: welding exhaust
« Reply #5 on: April 01, 2020 - 07:36:44 pm »
I'm mocking it up and the car is on he wheels on a 4 post lift.  the weight of the car is in place.  does anyone know how much clearance I need over he axle for suspension cycle or travel.  I have just under 3" on the drivers side but about 3.5" on the pass side.  I'm wondering if I should extend the over the axle pipe an 1" up and back down on the tail pipe section.  I tried to measure to the bump stop on hte frame but I just don't get a good look at the top of the axle tot he stop.  Does the suspension ever actually hit the stop?
John
73 Cuda
360 Crate motor
FiTech Fuel injection
727 Trans (wishing it had Over Drive)

Offline 70chall440

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Re: welding exhaust
« Reply #6 on: April 01, 2020 - 09:55:47 pm »
Generally you want the exhaust as high as you can get it without hitting the floor. Yes, the rear end can hot the bump stops under hard conditions depending on your shocks and leaf springs. That said, it does not (should not) happen often, so if your exhaust is slightly below the bump stop you will be ok unless you go 4 wheeling in which case the exhaust probably will not be at the top of your priorities.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline 'Cuda Hunter

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Re: welding exhaust
« Reply #7 on: April 01, 2020 - 10:09:50 pm »
Just curious, if you have a flux core welder, is it a mig?  Can you just change your wire and gas set up?   
"All riches begin as a state of mind and you have complete control of your mind"  -- B. Lee

Offline john h

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Re: welding exhaust
« Reply #8 on: April 02, 2020 - 08:14:43 am »
Generally you want the exhaust as high as you can get it without hitting the floor. Yes, the rear end can hot the bump stops under hard conditions depending on your shocks and leaf springs. That said, it does not (should not) happen often, so if your exhaust is slightly below the bump stop you will be ok unless you go 4 wheeling in which case the exhaust probably will not be at the top of your priorities.
my leaf springs are fairly new and I put he heavy duty ones in when I replaced them.  I have newer gas shocks but I hope to change them out for QA! single adjustable this summer.  I replaced my fronts with QA1 Single adjust and I love them.
John
73 Cuda
360 Crate motor
FiTech Fuel injection
727 Trans (wishing it had Over Drive)

Offline john h

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Re: welding exhaust
« Reply #9 on: April 02, 2020 - 08:23:36 am »
Just curious, if you have a flux core welder, is it a mig?  Can you just change your wire and gas set up?
My welder is Flux Core wire only.  just a budget one from Northern tool.  I can use .30 or .35 Wire.  the only thing convertible about my setup is the cart it's on has storage for gas and a chain.  HA!  I have been practicing quite a bit and on the old System and some new cutoff pieces that are thicker.  I get it tacked in about 4 places and then I take the flap disk to it again to clean it up and then I weld small amounts say maybe .5 " at a time with wire brush in between until its' welded all around.  Hit it with the flap disk again and then do longer welds for a 2nd pass.  cleaning up in between with the brush. The larger bead is nothing like a Tig weld but it's consistent and my car is driver.  IT's not up on blocks with mirrors. SO far I have only done this on the bench.  I will do as much as possible on the bench but at some point I will need to weld the over the axle stuff to the muffler and tail pipe while on the car.  Possibly I can slit the female ends and use clamps on the tail pipe.
« Last Edit: April 02, 2020 - 12:04:03 pm by john h »
John
73 Cuda
360 Crate motor
FiTech Fuel injection
727 Trans (wishing it had Over Drive)