Welding exhaust manifold?

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I have a 97 Jeep Grand Cherokee. I believe the manifold has a crack in it. I am assuming it is cast iron? Am I right you have to use a high nickel rod? Any recommendations on rod and any different technique with this rod? Thank You as always!!! I have a Lincoln AC225.
Reply:I've had 100% success with Ni99 filler, running stringers....no preheat of postheat.  I bevel out the crack, and weld it up.
Reply:Nickel 99 is what works best for me. Bevel, heat red, then weld with low amps and stick in a bucket of Speedi dri so it cools slow.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Could be cast SS. If it is, I would still follow the info Engloid and David gave you. Can't go wrong with good prep work.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:How do you tell if it is cast iron or steel? Where do you get the Speedi dri? I wonder if TSC carries those rods? I know they have a good variety of Hobart rods.
Reply:1)  If its an exhaust manifold, its cast iron.2) Speedi dri is available in any auto parts store  about $8.00 a bag.3) Yes Tractor supply carries Nickel 99.Go for it, show us picturesDavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:David, I had an old 1985 chevy 3/4 ton for a hundred or so years. It had cast SS exhaust manifolds. They had a lot of surface rust on them. I wonder if many other cars/ trucks have these??And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Originally Posted by RojodiabloDavid, I had an old 1985 chevy 3/4 ton for a hundred or so years. It had cast SS exhaust manifolds. They had a lot of surface rust on them. I wonder if many other cars/ trucks have these??
Reply:speedi dry, floor dry, grease sweep, ground clay, cheap kitty litter . if it's made from clay it's all the same. there's dozens of brand names
Reply:I don't suppose a small propane torch is gonna get it hot enough? DON"T LAUGH!!!
Reply:Hey, any preheat is better than none, IMO!Have a Jeep Cherokee?  Click Here!
Reply:Stick it in the oven for pre-heat.
Reply:Or you can braze it and avoid pre heat, post heat and slow cooling. I've had 100% success with it on exhaust manifolds for many years. Including the stick welded ones that later cracked or were just a mess to begin with.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Originally Posted by David RI don't think I have ever seen a stainless steel manifold on a "regular" car or truck unless it was aftermarket or on a vette or something like that.  I also was told by my weling instructor that once stainless is red hot, its not stainless any more.  But I DO see a lot of stainless exhaust systems and they work great.Back to the question.  Cast Iron makes small orange sparks that don't go but a foot from the work.   Steel makes yellow sparks that go a long ways like 7 feet.  Tool steel or hardened steel have tails on the sparks.I don't have a clue what stainless sparks look like from a grinder.David
Reply:Kook, got to get some rods from TSC and when I get started I will get some pics ofcourse. We all love pics LOL.
Reply:Vermiculite, the type used for packing things in (and which is often thrown away by labs which get chemical bottles delivered in it), is an ideal material to bury items in when slow cooling is needed.It is both an excellent insulator, is very light, and is capable of withstanding very high temperatures.It is actually a mineral which is mined and then expanded by heating.Vermiculite is also sold by gardening stores for addition to potting mixes, but may be somewhat wet when sold for this purpose . Obviously, the wet material won't work as well, but it can be dried out first.
Reply:Do I need any different technique burning this rod? Any guess on settings to get me close. Lincoln AC225 machine.
Reply:NI99 can be welded with AC.SA200,Ranger8,Trailblazer251NT,MM250,Dayton225AC,T  D-XL75,SpoolMate3545SGA100C,HF-15-1  RFCS-14 When I stick it, it stays stuck!
Reply:O.K. thanks I appreciate the info.
Reply:I agree with Jolly Roger on this one, I have always had better outcomes by brazing cast iron with a large V-prep rather then using the Ni99 rod.
Reply:Well, I got a chance to look at it today and it actually looks like regular steel tubing. The flange might be cast but the manifild tubing looks like steel. Anyway to tell for sure? I think I see the crack (not sure). If it is just regular tubing I can just bust out the HH187 and mig it up.
Reply:If you braze it you won't have to worry if it's cast or not. It works well on both. Make sure you have it good and clean. Cast iron is porous and soaks up the carbon from the exhaust as well as oils and such. After I clean and grind I flash it with my cutting torch with the cutting air kicked in. Brazing rods are cheaper than nickel rods.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Originally Posted by David R  I also was told by my weling instructor that once stainless is red hot, its not stainless any more.  David