I have to weld a crack in an exaust manifold and aint sure what to use, don't know if I should stick weld or mig it, and what type of rod to use if thats the case any help would be great thanks
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Thread: exaust manifold crack welding?
05-12-2006, 07:56 AM #1Junior Member
- Join Date
- Mar 2006
exaust manifold crack welding?
05-12-2006, 09:23 AM #2Senior Member
- Join Date
- Sep 2002
- Clark County, NV
I did one that is still on the road. I ground out the crack and used an old Eutectic rod that I don't know the composition of. The second pass was with E309 stainless.
Edit: Oh yeah, preheat and SLOW cool.
05-12-2006, 01:54 PM #3
Exhaust manifolds are hit and miss because all the good stuff is burned out. I just used 7018 when i did them years back. Cast or SS rod would be ideal if you want to spend the money...BobBob Wright, Grandson of Tee Nee Boat Trailer Founder
Metal Master Fab Salem, Oh 44460
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Spool Gun conversion. How To Do It. Below.
05-16-2006, 04:38 PM #4
That is the key to weld the manifold,first you preheat till the peice stops really stinking and starts to clean up (about 350 deg) on its own
Everthing depends on judgment ie ;material thickness ,so on age is a big thing because older cast tend to get brittle over time you can braze the peice if you want or stick weld it there are lots of good cast rods available if you choose that rouht make sure you peen between welds to releive internal stresses cover the peice in sand after or wrap it in a weld blanket and let cool slowlysmokin ana grinnin for 20 years
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05-25-2006, 08:41 PM #5Junior Member
- Join Date
- Sep 2005
I would braze it...
I have done several and I brazed them. I "V" out around the crack good and then I preheat them like they said. I then load it up with flux and have at it. I have even done one on my old 292 Ford that I cut the flange off and removed a section to adjust the angle, and then brazed it back together. That was 8 years ago...
I dont know if it was all necessary, but I had my Dad surface off the head sealing surface to make sure I didn't warp it...
Might be a low tech way, but worked quite well..
06-09-2006, 08:52 PM #6
heat the casting to a minimum of 350F, to bake out the oils and impurities, then let it cool. The weld repair can be done hot, with pre heating and cooling slowly, or it can be done cold. Due to the small cross sections of a manifold, it can be easily welded with Ni-rod or cast rods with little pre heat or post heat, so I will go with the cold method. Build a jig to hold the pieces in the right shape, then V-groove the joint 90 degrees, leaving a small root, 1/16" to 3/32", then grind the surface of the casting to clean up the porosity about 1/4" away from the joint. Use low heat, 60 - 80 amps for a 3/32 rod, and weld stringer beads, not more than 2 - 3 inches in length. Peen the weldment between passes, and let the casting cool between passes so you can touch it with your bare hand. The more peening during cooling, the better. Avoid weaving because it contracts the edges of the groove too much and causes cracking. I've used many different types of cast rods for repair, Ni Rod, Arctec supercast 80 and 90, Arctect cast 3, Certainium alloys, and another, Cronetron 211. Cronetron 211, as put, "the cast iron problem solver', is by far the best I've encountered in the past twelve years. Any of these electrodes will work, as long as they contain a sufficent amount of nickel. You want a rod that has a good elongation, so it doesn't allow cracking before you peen. Some electrodes are designed for hot cast welding, where temps are controlled for lengths of time, and some are more forgiving. After the joint is filled, you can grind the face reinforcement off and finish the weld repair with a needle scaler to give it a 'as cast look' which also relieves stress at the same time.