The Stovebolt Site Forums The Shop Area Engine Shop Welding pit marks on face of exhaust manifold

Tried to search for this so I thought I'd try this subject forum.
On one of my exhaust manifolds, the front face that bolts up to the head has rust pit marks on it. Similar to body work can I fill in the pit marks using a MIG weld and smooth them out with a file or will they not stick as the manifold is a casting. If not is there an alternative. I believe with the gasket on and bolted up it might not seal with the pit marks and all?
Thanks. Bob T.

I would try a good sandblasting to really clean them, then a furnace type cement. The gasket should hold the cement in place. Problem with welding is the heat. You could make things a lot worse. Have you tried a machine shop to have them cut down a bit. Its a pretty simple operation. If you are set on welding, try brazing them, the brass might stick better. Joe

I agree with Joe H. I wouldn't try welding, but brazing works reasonably well on cast iron- but you still have to be careful with heating and cooling or you will end up with the manifold cracking and being worse off than you are now.

Harvester

If they are cast manifolds they can be brazed as mentioned or welded with low hydrogen rod.

Here is a little secret that I have when it comes to welding cast-iron it is (Freedom Alloys Copper Head Rod) this stuff really works no preheating no supper long cool downs periods pretty much weld it as if you weld mild steel. Not a gimmick it works, and if you have to machine a part after welding it this is the only way to go the welds act just like the parent material no more braking tooling.

http://www.freedomalloys.com/pdf/92857.pdf

Thanks everyone for the info, I think I'll go with a high temp filler and see how it works. I wouldn't want to destroy the casting by trying to weld with my experience but if the gasket doesn't work than a machine shop it is. thanks again.
Bob T