Can exhaust manifolds be welded?

[Homerr]

I have a thru-hull manifold made by Nicson that is cracked and leaking water.<br /><br />Can these be welded? Will it be safe after welding?<br /><br />If it can't be welded, where can I find this manifold?<br /><br />Thnaks,<br /><br />H.

 

[FNG]

Re: Can exhaust manifolds be welded?

Cast Iron doesn't take a weld very well. Not with a Mig welder anyway. Maybe a Tig?<br />I think you will need to replace it.

 

[RTW5150]

Re: Can exhaust manifolds be welded?

I used to run a stock car and had cast iron heads welded several times. The piece needs to he heated up before it can be welded. Find a competent machine shop or speed shop, they should be able to do it.

 

[martyscher]

Re: Can exhaust manifolds be welded?

Years ago on the farm, an OLD welder fixed freeze cracks in our cast iron tractor block, but using nickel welding rods.<br /><br />Since cast iron expands a lot when heated a lot, it was mostly "weld a little, wait a lot", with tapping with a peening hammer during cooling.<br /><br />There may (hopefully)be an easier way today.<br /><br />Check with a good welding shop.<br /><br />Who knows, nowdays there may be something you can just squirt in and let dry!<br /><br />Good luck.

 

[GarageGuy42]

Re: Can exhaust manifolds be welded?

I have brazed cast iron before, but wouldn't have put it through a durable situation as on a boat engine. You should be able to find a welder that know's how. There is a process you have to go through to get it to take. Nickel rod on a stick welder is one but the heating process is another. If I recall you have to peen it to???<br />It would be worth a try over the price of a new manifold if you found someone that knew what they were doing.<br />That may or may not be of any help.

 

[FlyBoyMark]

Re: Can exhaust manifolds be welded?

Proper permanent repair of cast iron is to gas weld it with actual cast iron filler (3/16" square sticks) using special flux. The entire casting must be heated to dull red with a kerosene flame thrower (ice melters). And kept at a dull red appearence with the flame thrower while it is being welded with a soft flame gas torch. The cracks must be groved out with disk grinder at least 1/4" wide and almost to the full depth of the crack. After welding, the unit should be kept out of the wind and covered or protected till it is completely cool over nite otherwise it will crack again. All other forms of cast iron repair will fail eventually. This is a proven method from 20 years experince in my welding business repairing marine and automotive parts. This should be the only true acceptable method for repair. Ask the weldor if he knows how to gas weld cast iron with ACTUAL cast iron filler..if he cant answer or says no go somewhere else. Inspect the job before he welds and make sure in person he does what I have described. Most repairs that I have done on this type of job should cost the customer anywhere between 50-100 bucks per unit. If the manifolds are actually broken in half thru the water passages, they are junk.

 

[Homerr]

Re: Can exhaust manifolds be welded?

I appologize guys..<br />It's an aluminum manifold.<br /><br />I took it to a local shop, and he's seen a few of them broke where mine did. He said it will weld with no problems.<br /><br />Apperently there is a thin spot on it that can break. The previous owner must not have drained the manifolds before storage.<br /><br />H.

 

[FlyBoyMark]

Re: Can exhaust manifolds be welded?

Same procedure applies for welding cast aluminum except pre heating to only 500dg. in an oven. Tig weld with 5356 alloy only post heat in oven, turn off and let cool enclosed. Inside of manifold should be purged and filled with argon also while welding.