Cast iron welding

[spasm3]

I bought a cast iron casita. Its a fire place and pizza cooker. After 2 uses, the fire box cracked. Blue Rooster shipped another one no problem after i sent pics. They felt it was dropped in shipping and that led to it cracking.

But since i have a welder , i thought i would try and weld up the crack since i have a back up.

I drilled the ends of the crack to stop the progression.

I cleaned and ground the crack. Cleaned off a spot to ground the mig.

I used 309 stainless wire. This wire seems to run hot.

I built a fire and got the cast iron good and hot. Then i mig welded it.
I had to stop some, as my gloved hand got hot as i rested it on the stove for support. It still was not easy to weld on a really hot surface, and steady my hand.

Its not be best beads i've ever done, but turned out pretty well.
question is, should i grind it down? Or just leave it for the surface strength and go ahead and paint it flat black?

I don't know if the welds will hold or if i will have other cracks form outward from the welds. Time will tell.

Pics below from new, to cracked to welded.

 

[spasm3]

Blue Rooster has great customer service, here is the new firebox they shipped me.

 

[53' Stude]

I think you did a good job on that sir

 

[tig1]

309 SS is the wrong alloy for cast iron. There are stick rods designed for cast that are also machine able if holes needed to be re-drilled or other types of machining. However hope your repair works well for you.

 

[spasm3]

309 SS is the wrong alloy for cast iron. There are stick rods designed for cast that are also machine able if holes needed to be re-drilled or other types of machining. However hope your repair works well for you.

Thanks, i knew there were sticks for it. Not sure there is any mig wire for this. Basically it was a practice and see what happens. I have another brand new fire box if it does not work.

Should i grind it down, or leave it as is and paint it?

 

[4WD]

Flat black high temp … cheese and Canadian bacon …

 

[tig1]

Thanks, i knew there were sticks for it. Not sure there is any mig wire for this. Basically it was a practice and see what happens. I have another brand new fire box if it does not work.

Should i grind it down, or leave it as is and paint it?

There is cast mig wire, but the price is way out there. Better off buying 4-5 stick rods. No, I would not grind off the weld, but as said, there are paints designed to handle heat.

 

[BlueOvalFitter]

If you don't grind it down, just don't walk too close to it. That weld will snatch your drawers from your pants!


J/K. Leave it alone.

 

[spasm3]

If you don't grind it down, just don't walk too close to it. That weld will snatch your drawers from your pants!


J/K. Leave it alone.

lol its not the smoothest, i ran it a bit cold, as to not over penetrate or overheat the cast iron and make more cracks. But it is standing out there!

 

[ecotourist]

About 70 years ago an uncle sat on the oven door of my mother's black and chrome kitchen stove and broke one of the hinges. Someone brazed the pieces together. It worked fine but you could always see the repair of that chromed cast iron part.

That repair lasted for 20 or 30 years until my mother bought an electric stove. I don't know what happened to that old stove - it was a good friend.

 

[OIL_UDDER]

Well done.

 

[Ihatetochangeoil]

Stainless steel filers are not a good choice when you want to weld cast iron. Because high amount of chromium in filler and high amount of carbon in cast iron combine together to make some carbon reached chromium carbide which is brittle.
However, it appears your particular application is purely aesthetic with no tensile, shear, vibratory, or compressive stress. It may work...If it does NOT work, that is to say, if it cracks and you wish to repair it again, step 1 will be to remove ALL the stainless filler; buy a 1/8" thick grinding wheel and "dig" a Vee, or channel or U-groove, whatever you wish to call it, cast iron electrodes will NOT "penetrate" into the base metal, there needs to be "room" for the weld bead to lay. You COULD even obtain a cast iron bar to use behind the weld as a backer if it would be out of site.
Use NiRod 55 (ENiFe-CI) or NiRod 99 (ENi-CI). A low dilution welding process would be preferred. Preheat will need to be at least 400-500 F minimum.
You can buy 5 pieces of 3/32X12" electrodes Ni55 ENiFe-C1 on Amazon for $10.99 https://www.amazon.com/Repair-Stick...ROD+welding+electrodes&qid=1604889598&sr=8-10 You're going to want to use DCEP at 50-70 amps and run down hand like you did with the stainless. Here is a technical sheet on the rod: https://www.specialmetals.com/assets/smc/documents/smw/we55.pdf
If you were to do this, build the weld to only slightly above surface reinforcement, then you can grind the face off with a 40 or 60 grit wheel, then take a flapper disc (tiger paw) and gently sand & polish the weld face to be flush with the surface. https://www.amazon.com/Performance-Abrasive-Phenolic-Zirconia-Diameter/dp/B07JZMGLBY
After this, I'd ask the manufacturer for some touch up paint and the repair could be made invisible. Best of luck to you!

 

[jhellwig]

If I had a choice I would have brazed it. But working with stuff on hand it works. It isn’t structural or a working part so it is fine. It looks like the parts of it are welded to begin with. Most likely isn’t cast iron anyways just some low grade recycled metal they cast.

 

[spasm3]

Stainless steel filers are not a good choice when you want to weld cast iron. Because high amount of chromium in filler and high amount of carbon in cast iron combine together to make some carbon reached chromium carbide which is brittle.
However, it appears your particular application is purely aesthetic with no tensile, shear, vibratory, or compressive stress. It may work...If it does NOT work, that is to say, if it cracks and you wish to repair it again, step 1 will be to remove ALL the stainless filler; buy a 1/8" thick grinding wheel and "dig" a Vee, or channel or U-groove, whatever you wish to call it, cast iron electrodes will NOT "penetrate" into the base metal, there needs to be "room" for the weld bead to lay. You COULD even obtain a cast iron bar to use behind the weld as a backer if it would be out of site.
Use NiRod 55 (ENiFe-CI) or NiRod 99 (ENi-CI). A low dilution welding process would be preferred. Preheat will need to be at least 400-500 F minimum.
You can buy 5 pieces of 3/32X12" electrodes Ni55 ENiFe-C1 on Amazon for $10.99 https://www.amazon.com/Repair-Stick...ROD+welding+electrodes&qid=1604889598&sr=8-10 You're going to want to use DCEP at 50-70 amps and run down hand like you did with the stainless. Here is a technical sheet on the rod: https://www.specialmetals.com/assets/smc/documents/smw/we55.pdf
If you were to do this, build the weld to only slightly above surface reinforcement, then you can grind the face off with a 40 or 60 grit wheel, then take a flapper disc (tiger paw) and gently sand & polish the weld face to be flush with the surface. https://www.amazon.com/Performance-Abrasive-Phenolic-Zirconia-Diameter/dp/B07JZMGLBY
After this, I'd ask the manufacturer for some touch up paint and the repair could be made invisible. Best of luck to you!

Wow ! Lot of info there!

You and Tig1 really know your stuff. Thanks for the education!

 

[ABN_CBT_ENGR]

Its not be best beads i've ever done, but turned out pretty well.
question is, should i grind it down? Or just leave it for the surface strength and go ahead and paint it flat black?

Late to the party but must commend your work given what you had to work with, pretty certain it will functionally last.

Don't dress it, just cover it and go