Welding/Build question needs some help with cast iron to cast steel weld.

[rob989_69]

I got my second air tank to use as a firebox yesterday. The "problem" is that I think it's cast iron, where the other tank is cast steel. The main cook tank rings like a gong when I hit it with a hammer, the new tank is just a dull thud. 

So the question. Will there be any issues welding the two together? I won't be doing the actual welding I have someone with a good bit of experience doing it for me. My concern is more the heat/cool cycle and if I'll need to worry about the welds breaking or anything else I may not be aware of?

 

[sunman76]

Yes it can be welded, sometimes welding cast iron might make a preacher say a dirty word..

..

If your welder is knowledgeable about working with cast iron it will work, but IMHO I would look around for a good steel tank

to use to save the trouble of having something crack later down the road.

 

[alelover]

You need to be real careful welding cast iron. An experienced welder will be needed. One that has welded cast iron before. It is very prone to spider cracking and you can end up chasing the cracks and ruining the piece. It can be done but it takes a highly skilled individual. I can't remember what rod to use.

 

[raygunter]

Now I'm not a welder by trade...... just a dobber.

I've had best results by heating the area around where the weld will be to reduce the localized stresses brought about by the welding heat.  Pre-Heat the area out to an 8-10 inches span.  The pre-heat dosn't have to be red hot, 3-4 hundred degree will be plenty. 

 

[daveomak]

rob, morning.....   A dull thud indicates a crack some where...... 

Nickel 99 is one rod to use....  To be safe I would drill and bolt the pieces together... 

Sunman's idea is the best choice.... look for a new tank....  Dave

 

[rob989_69]

Thanks guys. I'll keep my eyes peeled for something else. I also like the bolt it together method if I can wing it. I'll talk to the welder and see if he's worked with it before.

 

[alelover]

Nickel rod. That's it. Thanks Dave. Don't know why I couldn't remember that.

 

[boykjo]

you can also preheat and tig with stainless. Here is a repair I did on my lawn mower axle. Thew it in a bucket of sand to slow the cooling down

Joe