Welding question - cast iron to black pipe

[JetSmooth]

I have plans to learn to weld to build a small frame for the brewing setup. In the mean time, I am designing a stand for a corona mill to be pedal powered.

The base for the mill will likely be black iron pipe with the corona mill mounted on an upright pipe. I could devise a fancy table top mount to clamp it to, or I was thinking I could cut the clamp off and mount the pipe (or a threaded coupler) directly to the bottom of the mill. If the iron pipe and cast iron were cleaned really well, could they be welded together?

If it's possible, this should be a pretty simple weld, I think. I may take it to a shop rather than tackle it myself (since I'll be cannibalizing a corona mill). Or if there's anyone in the area who welds, give me a shout. I'll ower you a case.

 

[Steel]

It should be no problem. You would want to stick weld it with NI-rod. At work we use 1/8" NI99

 

[JetSmooth]

Cool. Think I'll gather all my materials together and take them to a local place. That's all Greek to me.

 

[LarMoeCur]

You really can't weld cast iron. You can braze the pieces together with welding rod but is not going to be very strong. It boils down to how do you join two different metals or three if you count the welding rod. It sounds like there will be some stress on the area your talking about. In my opinion it will not hold. I'm no welding expert by the way.

 

[rockytoptim]

Cast iron can be welded but its very very difficult. I would look at other options.

 

[dmfa200]

To make the weld work without cracking the pieces should be preheated to 500F, welded and kept at that temp. until the welding is completed. Then let it slowly cool for as long as possible.

Cast Iron will crack if not preheated, and/or quickly cooled. Even by ambient air. Covering the weldment with hot sand will help slow the cooling. Or it can immediately put into an oven and slowly bring down the temp.

The cast will crack at the toe of the weld if not done properly, but it can be done. You just have to know what your doing.

 

[dmfa200]

You really can't weld cast iron. You can braze the pieces together with welding rod but is not going to be very strong. It boils down to how do you join two different metals or three if you count the welding rod. It sounds like there will be some stress on the area your talking about. In my opinion it will not hold. I'm no welding expert by the way.

Sorry, but that's wrong.

 

[lincoln]

dmfa200 is on for a welding procedure, i would still vote to braze it. you wont have to worry about pre and post heating and with decent joint prep will be plenty strong.

 

[JetSmooth]

'Splain the brazing process for me then.

 

[LarMoeCur]

You know the sound your car makes when it's cooling off. That PING or TINK sound. If hear that sound at any point the the welding or cooling process the weld has cracked. I've brazed cast iron manifolds for cars and it's almost impossible even with pre-heating to not get a crack. What works best for me is pre-heating the cast part then brazing a small bit. Re-heating and brazing some more. Re-heating continually until it's completely brazed. Then I put it back into the oven and slowly bring down the temp over time. Listening for that tell tail TINK. If I hear it, I pull it out and inspect. Every time I've heard the dreaded TINK I could see the crack or gap in the braze. Really the only reason to attempt this brazing is if you couldn't find a replacement part. Which is the case for most old car restorations. In your case I'd attempt to round off the base and tread with a tap and die before I attempted to weld. just my .02

Your going to need to use a oxygen acetylene welding setup to braze. I do not think you will be able to get adequate adhesion to either the cast iron or the iron pipe. Once any force is applied to this joint it will snap for sure.

 

[Toga]

Brazing is the only way to go with cast iron.

 

[lincoln]

 

[GreenMonti]

Pedal power?? I picture you sitting on a exercise bike with the mill attached to the handle bars.:rockin:

Whether you, or if you have a shop do the welding, or the brazing. IMO, its a lot of hassle and money to mount the mill that way. A small piece of wood attached to the pipe stand via a couple U-bolts or a small piece of square tube welded to the pipe should do the trick. Cast iron is just a PITA to deal with. Let alone cheap cast iron like a corona mill.

 

[mattmuir]

I am not a certified welder but have bee doing it for years as a hobby..love to build stuff. I also live on a small farm and find all sorts of things from neighbors (real farmers) when I get home from work that need fixing. I have welded tons of cast iron stuff from manifolds to pto couplers over the years. I always tell them this should be heated and a special rod used but I can give it a shot. I have had the best luck using a mig at low heat and keeping the runs short so not to get too hot. I have tractor manifolds that were done years ago that are still fine. Even an old pot belly that has had many fires and heating and cooling cycles. Dont know if it should work, but it seems to work for me.

 

[toolboxdiver]

I have plans to learn to weld to build a small frame for the brewing setup. In the mean time, I am designing a stand for a corona mill to be pedal powered.

The base for the mill will likely be black iron pipe with the corona mill mounted on an upright pipe. I could devise a fancy table top mount to clamp it to, or I was thinking I could cut the clamp off and mount the pipe (or a threaded coupler) directly to the bottom of the mill. If the iron pipe and cast iron were cleaned really well, could they be welded together?

If it's possible, this should be a pretty simple weld, I think. I may take it to a shop rather than tackle it myself (since I'll be cannibalizing a corona mill). Or if there's anyone in the area who welds, give me a shout. I'll ower you a case.

yes this is very difficult you need to pre heat and then put the piece in hot sand to cool slowly I would recomend making a flange for the pipe and bolting the cast mill to it then you can screw the pipe in

 

[rollinred]

Do not weld this project. It is possible to weld cast but in this instance completely unnecessarily difficult. Just heat the crap out of the pieces and braise them. This will more than likely result in a better joint than welding. A welded cast piece is going to crack after time. It is not a mater of if it will crack but when. A good cast weld will usually last, but not near as long as a braise will in this case.

If temperatures were highly fluctuating, as in 800 degrees either way (exhaust manifold) I would tell you different.

 

[Steel]

I am not a certified welder but have bee doing it for years as a hobby..love to build stuff. I also live on a small farm and find all sorts of things from neighbors (real farmers) when I get home from work that need fixing. I have welded tons of cast iron stuff from manifolds to pto couplers over the years. I always tell them this should be heated and a special rod used but I can give it a shot. I have had the best luck using a mig at low heat and keeping the runs short so not to get too hot. I have tractor manifolds that were done years ago that are still fine. Even an old pot belly that has had many fires and heating and cooling cycles. Dont know if it should work, but it seems to work for me.

I agree 110%. Everyone is making this out to be such a difficult thing. Cast iron and aluminum welding always have such a bad stigma as being "difficult" but from a real life stand point there's nothing difficult about it if you know what you're doing. Most people here are speaking as an armchair welder. but YMMV

 

[JetSmooth]

Pedal power?? I picture you sitting on a exercise bike with the mill attached to the handle bars.:rockin:

Whether you, or if you have a shop do the welding, or the brazing. IMO, its a lot of hassle and money to mount the mill that way. A small piece of wood attached to the pipe stand via a couple U-bolts or a small piece of square tube welded to the pipe should do the trick. Cast iron is just a PITA to deal with. Let alone cheap cast iron like a corona mill.

Well, I want to make a compact rig that you pedal from a chair sitting in front of it, but that's the basic idea. Not a whole bike, though. Haha.

I'm sort of thinking your idea of mounting it on a piece of square tube might be the best option at this point. I was trying to reduce height and make the appearance a bit cleaner, but it sounds like a headache to weld correctly and I'm not paying out a lot for this job.

 

[Caboose]

My experience with welding Cast Iron is that you have to take your time. If you try to weld more than just a tiny area at one time you will crack it. Brazing is the best way to go if you have the tools. If you only have a welder you can do it, but like I said, take your time, the slower the better.

If you have some scrap pieces you could mock up I would practice on that first!

 

[dmfa200]

Well, I want to make a compact rig that you pedal from a chair sitting in front of it, but that's the basic idea. Not a whole bike, though. Haha.

I'm sort of thinking your idea of mounting it on a piece of square tube might be the best option at this point. I was trying to reduce height and make the appearance a bit cleaner, but it sounds like a headache to weld correctly and I'm not paying out a lot for this job.

Welding cast is normally done as a repair. I just wanted to be understood that it can be done, and is not terribly difficult.
Brazing would be easier, but I'm sure there are a handful of even easier options.

Sometimes we all get tunnel vision when thinking of how to do something.
Forums are a great opportunity to get more than one brain thinking of a solution. Everyone's brain processes information differently, and therefore you usually end up with a totally different, and often simpler solution to an equation.