welding cast iron gas burners

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hi, so if you've seen my other posts you know i'm fairly new to welding. probably only about 20hrs weld time and i just picked up a 210 MVP. with that said i have a project at home. my dad has a restaurant with big gas grills. well each grill is about 5' x 4' and has 4 cast iron burners. eventually the burners crack and have to be replaced so we just replaced 4 of them which means i have 4 broken ones at home that i would like to fix. how would i go about doing this? i've read that you can pre-heat it and weld it together, would this work? these dont have to be incredibly strong but they are only supported on the ends and not the center and each weighs about 30lbs. any ideas would be much appreciated.if i'm missing any information please let me know. thank you
Reply:I am curious to see what the very experienced guys say here. I suspect that the heat cycle and weight that the grills under go will prevent successful repair.                                            Regards,Ed
Reply:The things that could go wrong with a repair like this outweigh the value of the part. I recommend that you throw it away and keep replacing them as needed.Two turn tables and a microphone.
Reply:pics would be nice of the burners in the grill and of the broken ones.225NT bobcatAEAD200LEScott 125mm175, mm252 w 30A, PT225mm211, TA 181iHyper Therm 380, cut master 529100X & XX, Digital Elite6 Victor setssmith little torch, meco midget kalamazoo band sawsteel max saw evoulution circular saw
Reply:thanks i'll try to get those as soon as i can. i know the heat cycling will def. affect it the most and i'm replacing the broken ones but i have these at home so i can experiment haha
Reply:you say they are not supported in the middle, only on the ends. where are the cracks occurring? in the middle? the reason i asked, if thenew ones could be supported in the middle by a bracket you could fab it might relieve stress that's causing the failure.Last edited by jbmprods; 01-12-2012 at 01:08 PM.225NT bobcatAEAD200LEScott 125mm175, mm252 w 30A, PT225mm211, TA 181iHyper Therm 380, cut master 529100X & XX, Digital Elite6 Victor setssmith little torch, meco midget kalamazoo band sawsteel max saw evoulution circular saw
Reply:yes, in the middle. there is a support bar in the front and back that i replaced. i have to do this about once a year because the heat causes it to bend in the middle leaving the burner unsupported. i've thought about welding a support in the middle but the entire grill is stainless so i don't know if i can weld a steel bar to that.
Reply:so drill it and bolt or screw it.225NT bobcatAEAD200LEScott 125mm175, mm252 w 30A, PT225mm211, TA 181iHyper Therm 380, cut master 529100X & XX, Digital Elite6 Victor setssmith little torch, meco midget kalamazoo band sawsteel max saw evoulution circular saw
Reply:Originally Posted by superwelderyes, in the middle. there is a support bar in the front and back that i replaced. i have to do this about once a year because the heat causes it to bend in the middle leaving the burner unsupported. i've thought about welding a support in the middle but the entire grill is stainless so i don't know if i can weld a steel bar to that.
Reply:Originally Posted by jbmprodsso drill it and bolt or screw it.
Reply:Originally Posted by BistineauThis is a Welding Forum, not a Drill, Bolt & Screw Forum, see my last comment.
Reply:Originally Posted by superwelderyes, in the middle. there is a support bar in the front and back that i replaced. i have to do this about once a year because the heat causes it to bend in the middle leaving the burner unsupported. i've thought about welding a support in the middle but the entire grill is stainless so i don't know if i can weld a steel bar to that.
Reply:i'll get pics as soon as i can. a screw would never hold up in this grill. the body is sheet stainless and a screw would not be strong enough. right now the 2 bars that are welded to it are 1x1 square steel and it is welded to the body and is very strong. i wanted to weld the burners together and maybe keep them as back ups just in case one breaks so bad that it can't be used, this way i won't have a long down time.
Reply:You should be able to weld them back together. I preferr the UTP rods for cast iron, with the 85FN the best for this. You won't need any pre heat or post heat with them. It is, however, critical to grind a "U" groove and not a "V" groove. Weld an inch and beat the flux off. The flux is tough and by the time you have it beat off you will have relieved the stress you imparted into the metal. Weld another inch and so on. If it is dirty cast the first pass will likely be full of pin holes and you won't get much penetration. Grind it out and start over. The third or fourth pass and it will look perfect.
Reply:BooYah! Weld 'em up. Kick the cat out of the sandbox, get some preheat into them parts, then weld 'em. Put some post heat into 'em, then bury them in dry sand over night. {Shade tree WPS. }Preheat to 800* F., over the entire project. They can be stick welded, or oxyacetylene welded. (Your MVP is not really going to work here.) Then keeping the heat up over the entire project, bury it in dry sand for 12 hours to slow-cool. It's worth a shot, and practice will help you get it right eventually. Try it out on some scrap iron first to get an idea of how it handles.That is what I have been taught.I have a wood stove that I want to take a shot at, once I get my 'round tuit.Last edited by tanglediver; 01-12-2012 at 10:55 PM.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Because of the heat you don't want dissimilar metals. Nickel and stainless filers are out.  You would have to use a cast iron filler which requires preheat and more importantly, a controlled post heat.How about fabbing up some new burners out of a more heat resistant material like 309, 321, or 347 stainless?  If they're small, material costs could be reasonable.
Reply:never thought about making new ones. but i don't think it would be worth it honestly. so, i think i'll start looking for a oxy setup, had to get one anyway, now i have a reason.
Reply:You say you have some old broken burners.  Cut filler metal out of one or some of those to gas or TIG weld the othersGordie -- "I believe you understand what you think I said, but I'm not sure you realize that what you heard is not what I meant."
Reply:I've came across some of these burners that were impossible to weld because of the type of casting elements. If after doing all the right things and using proper methods it doesn't want to weld dont waste any more time on it.Certain type of casting cant be welded.
Reply:The heat cycles are killing your parts.  Welding them will put different stress on them making them crack again.  Do it anyhow and see.  Where are the pics?Real world weldin.  When I grow up I want to be a tig weldor.
Reply:even if he does succeed in welding them up and he tries to use them in the stove and they crack or worse yet break and a cook is injured from misdirected flames, the cook will own the restaurant after the liability suit. this is why i suggested making a mount to prevent new burners from failing in the future. be it welded to the thin pan or welded to sandwiched plates bolted to the pan, it seems the better way of dealing with the future problem with not much chance of a lawyer getting involved.225NT bobcatAEAD200LEScott 125mm175, mm252 w 30A, PT225mm211, TA 181iHyper Therm 380, cut master 529100X & XX, Digital Elite6 Victor setssmith little torch, meco midget kalamazoo band sawsteel max saw evoulution circular saw
Reply:heres the pics, sorry i forgot to mention before but these burners are not fueled under pressure. there a injector that shoots a stream of NG in there and it just floods the burner and burns through the holes. yes one burner has a section that is broken off completely, i have the piece but i think i'll practice on that one.also, you'll notice that one has a small hole in it. thats from a stand that broke off. not really necessary because there are 4 more and they just hold the grease guard up.thanks Attached Images
Reply:I'm not sure about CA health dept. rules, but anything added to the stove will probally have to be stainless, resturant grade. Welding the burners is a waste of time. If you have access to oxy/acety. you can braze them. Nothing will hold it better. Cool it slowly sand works great, but not every body has a sand box around. You can wrap it in a couple of  layers of heavy fire blanket. if this is not done when they are heated up on the stove they will crack again just outside your weld good luck.
Reply:I dont know how much these cost to replace but the cost of Ni rod is about $ 40.00 a lb last I bought any which was about 10 yrs ago........Thats alot of cash for what I bet is a $25.00 grate. One pound of 1/8" rods equals about 13 rods......cant repair many grates with 13 rods. My opinion.........buy new. The idea of adding support braces is a good one depending on the design of the cooker.A young green pipe welder asked an old salt one day...How can I make the weld on the bottom of the pipe look like the top.......The old salt replied....Screw up the top......
Reply:Just solve the issue that is causing them to break in the first place. You will not be able to successfully weld those burners, You may be able to get them stuck together, but all the thermal cycling in those has burned the metal right out of them. There is nothing left but a crystalline looking stuff that is extremely fragile and it will break right next to where you stuck it together. The only thing a new welder can learn from trying to weld this type of thing is frustration and disappointment. Also, if they are getting hot enough to do that, then brazing will not work either. It may get them stuck together, but will soften and the burner will sag and break quickly. You don't say what the burners cost, but you could make a replacement out of steel pipe fairly quickly. Also, you are going to continue to have these sorts of issues until you get the appliance tuned properly. Most likely you are not running an appliance regulator for it, so it is running at too high  pressure. Second most likely is that the air shutters are mostly closed causing yellow flames, which soot up everything above the burner, causing the flame to sink lower in the BBQ cavity, heating up the burner.thanks for that insight. i'm def. going to look into welding in a center support as soon as i can. as for the burners, they're 250 each 5 per grill x 4 grills.
Reply:Hey superwelder, IMO, if you're welding it for the hell of it, then go ahead, just realize there will be costs for your experiments. But hey, many people weld as a hobby, so just treat it like that. But if you're thinking of using them in the future, you should probably think about it a little more. I just started welding (MIG). It will be a long time before I weld anything that might be used for something important, I might even take a class. But good luck, have fun, and be careful.