Cast iron grate repair

I just got a call from the guy I buy my compressed gasses from wanting me to weld up some cracks in a stove grate . I'm thinking plain phosphor bronxe
filler might not take the heat , and am looking for opinions on what to use . Looks like my choices are Ni-99 , Ni-55 , silicon bronze . or cast iron filler . Will CI or SB require peening , like the nickel does ? Or is
the grate in/on firebricks to retain the heat while I work on it or possibly bury it in dry sand . Which would you use ? I do know that whatever I use it's going to need preheat and a slow cooldown . I'm thinking a nice wood fire could handle both since I don't have anything else to preheat a piece about 11 x 13 . He won't be bringing it for a couple of weeks , so I have time to order some filler as soon as I decide which to use .
--
Snag



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wrote:


Greetings Terry, I'm not sure which of the rods mentioned above is best for your job but I do know that there is a rod available for stick welding cast iron alone or welding it to steel. I used the stuff years ago and it worked very well and I think I bought it at the hardware store.I think it was the Ni-55. In fact, I'm almost positive that's what it was. Your idea about pre-heating is a good one. When I weld cast iron I use ceramic blanket material that I buy from Seattle pottery supply. I like the stuff because it is real easy to make a form fitting oven. When I use it I lay it on the welding table, lay the part on the stuff, and I pack it around the part as close as possible. If the part is heavy I will lay fire brick on top of the blanketand lay the part on the fire brick. I then use a weed burner to heat the cast iron so that it is very hot. Then welding commences and as soon as I am finished welding I cover the part with the blanket to cool slowly. Since I started using this method I have not had any parts with cracks once cooled. A couple jobs I have done had such thin cross sections being welded I worried about strength after welding. So I welded some mild steel reinforcements to the cast iron. Eric
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On Friday, November 20, 2015 at 11:43:02 AM UTC-5, Terry Coombs wrote:

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I do not have much experience welding cast iron. But read
http://www.lincolnelectric.com/en-us/support/welding-how-to/Pages/welding-c ast-iron-detail.aspx From Lincoln Electric.
It only mentions peening when you do not preheat. When you do not preheat , the weld shrinks on cooling and the cast iron does not. So you peen the weld to make it expand. I think the NI-55 shrinks less than NI-99. and m ay have about the same thermal expansion as cast iron. I am just guessing here. ( invar36 is 36 % nickel. Invar -41 is 41 % Ni. INvar 36 has less thermal exponsion acound room temperatures , but invar 41 has less thermal expansion at higher tempertures. ) But Ni-99 is softer and will yield .
I would probably go with NI-55 as it is a lot cheaper than NI-99. But if y ou preheat you could probably use CI rod.
Dan
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On Friday, November 20, 2015 at 8:34:51 PM UTC-5, snipped-for-privacy@krl.org wrote:

Dan
I wandered around the internet and found a site ( welding tricks ...jody ) that mentioned using 312 stainless rod on cast iron.
I am pretty sure that I have some invar 36 and invar 41 tig rod and could cut some to fit in a flat rate box. But as I remember it is all 1/16 dia. Let me know if you want some.
Dan
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On 11/20/2015 11:42 AM, Terry Coombs wrote:


I know what a pain these kind of jobs can be and I wish you luck! I would truly like to see a before and after and explain your process.
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wrote:

$499 Annie (OOS, but the parts are in) $741 Roy
See 'web store' button on fluxeon page.
Gonna buy two? They're small.
--
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Gunner Asch wrote:

Propane torch and a pan of water ?
--
Snag



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wrote:

Don't forget the lazy susan base.
--
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which difficulties disappear and obstacles vanish into air.
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