Moparts Tech Archive

Exhaust

Welding cracked exhaust manifold?

I have heard various reports on welding cracks in exhaust manifolds. Has anyone had any luck? Is this a job for gas or stick? Any better methods?
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CDignition
Moparts Member
Posts: 3066
From:
Registered: Mar 2001
posted 06-29-2002 08:38 AM

Needs to be preheated, Using a Tig Torch with NiChrome wire...Flame spray works too, but is somewhat involved..
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fast71
Moparts Member
Posts: 812
From: Old town,fl,usa
Registered: Oct 2001
posted 06-29-2002 08:59 AM

cd is right faust,,a stick welder will not get the iron hot enough for the weld to be affective,i have repaired cracks and have welded alot of broken studs with getting the iron cherry red,all around the area and using a good flux brass welding rod and letting it puddle up and keep working the area around the weld keeping it cherry red ,so as to get a permanent weld.you can then grind the area back into shape and paint it or whatever,
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shwing.er
Moparts Member
Posts: 631
From: south bend, indiana
Registered: Jan 2002
posted 06-29-2002 09:56 AM

i have welded many a manifold using stick welder and nickle rods....
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DRAM
Moparts Member
Posts: 4212
From: West Palm Bch. Fl.
Registered: Jun 2000
posted 06-29-2002 08:00 PM

it's not hard to fix. go get a few nlw 5565 rods, stop drill the crack and clean the surface really well. you can cold weld if it's not a real wide crack. no more than 1/2 inch at a time, remove slag, let it cool for a few minutes and repaet until your finished.
if you choose to you can preheat the iron, turn the welder down to about 85-90 amps with a 1.8th rod and weld it up. be careful not to burn through. keep the heat on the manifold and every couple of minutes decrease the amount of heat. when the torch is about 10 inches away you can shuit it off and let it air cool. all done. i have to weld cast iron pretty frequently and can't alway's get the part to the mig from the construction site.
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SCVpiper
Moparts Member
Posts: 129
From: Castaic CA USA
Registered: Nov 2001
posted 06-29-2002 09:36 PM

i cranked the heat all the way up and the feed almost all the way up on my 110 mig and the weld lasted 100k miles on my 56 dodge manifold
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