Help - repairing a fire dog.

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My friend asked me to fix his fire dog (or andiron). This is an old, probably antique, item made out of cast iron. Please help me with ideas to weld or fix. I can stick weld, but consider myself a high level beginner. Would I cut a groove and stick weld? What rod?I have mig, but don't think that will work except maybe for fixing by using angle iron to reinforce/brace. I thought about running 1" angle to make an "H" on both sides and top and bottom. Any ideas on that?Thanks for your help. Picture show from bottom. Attached ImagesBurt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:The 'classic' electrode/filler for welding on cast iron is a nickel-based filler.Because cast iron is so high in carbon, if you use almost any steel filler/rod/electrode you end up with a weld bead that is steel and so high in carbon that it is super brittle.  Which then usually cracks with a TING! as the weld cools.So the 'classic' way the weld cast iron is to heat it ReallyDangHot (about 500-1200F, weld it with nickel filler, and then let it cool ReallySlow (as in overnight).http://www.lincolnelectric.com/en-us...on-detail.aspx  The best laid schemes ... Gang oft agley ...
Reply:Hey Moonrise.I thought it would require a nickel rod, but did not know about the preheating. I'm not equipped to preheat it. I appreciate the link - and the article mentions another method of not preheating but trying to keep it cool overall. Using that method, it says to only make short 1" welds. Since the whole thing is only 1" wide, do you think I have a chance to just weld using nickel rods at room temp? Or I could weld it outside and it would be close to the 100 degrees they recommend. I assume I need to grind a groove all the way around each end. Again, thank you for the help. Any other advice is welcome.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:My approach?  Groove it, heat it, weld it, cool it slowly.  Worth what you paid for the advice.  Heat?  You claim you have no way to preheat it.  Have a gas or charcoal BBQ grill?  You have a way to heat it.  Have a place where you can get a campfire or 'small' bonfire going?  You have a way to heat it.  You or your friend has a fireplace?  You have a way to heat it.  For cooling, put it back in the fire and let it cool as the fire dies down, or bury it in hot dry sand or  ash or such, or wrap it in a welding blanket and let it cool that way.You don't need a full-up temperature-controlled-to-the-degree inert-gas-filled heat treat oven after all.    The best laid schemes ... Gang oft agley ...
Reply:OK, trying to get my courage up to try this. I have never preheated anything to weld it. So if I can get some charcoal going and heat it up until it is red, then pull it out of the fire, won't I need to clamp it or something to keep it lined up straight? Is there an easy way to do that with red hot iron? Should I build a jig to hold it or ? Do I heat the whole thing and not just the place to weld? If just the joint, I have a little propane torch that might work but don't think it is big enough for the whole thing.Then weld both sides at once and throw it back in the fire? Man, I like welding and fire, and all, just trying to get my mind around this because I'll only have 1 chance to do it right.  <- this might be me with RED HOT IRON.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:Have you considered brazing it??
Reply:Hi, AKPolaris.I considered it, but since I don't really know how or have the equipment I went on down the list.Thanks for the comment. Still open to suggestions and education on cast iron.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:I'd recommend heating it with propane (just a weed burner and a cheap laser thermometer).  Heat it to about 800f.  Weld it with 99 nickle rod, then cool it slowly by either setting it in a camp fire and letting the fire burn down to coals and cool slowly with the fire dog in it or by covering it with sand (casting sand preferred) and letting it cool slowly with the sand to insulate against rapid heat loss.As a disclaimer, I've only done this once so far...worked fine though.  Basically, I took a bunch of advice from other people on here asking the same thing and did it that way.  Now if I had a rare cast engine block or something unreplaceable or really expensive, I'd send it off to CastWeld and have him do it.--Wintermute"No man's knowledge here can go beyond his experience." - John Lockewww.improvised-engineering.comManufacturer Agnostic:Blood----------Sweat---------Tears----|------------------|----------------|----Lincoln Red, Miller Blue, Esab Yellow
Reply:I don't want to bust your bubble but you may be very dissapointed with welding a burned up cast Iron andiron.  Ive tried to weld a few in my life and if you can get anything to even stick to them you are lucky. and then about the second time someone puts a stick on the fire they fall apart. If he is a good friend make him a pair out of railroad track, they will last forever.   Mac
Reply:Hi, Mac the Tool Maker.That was one reason why I had asked in the first post about just framing around it with 1" angle iron. I could cover the top and bottom with an "H", weld it very solid and it might be stronger than welding the cast iron. That is well within my skill and experience level, which is limited.Any thoughts on doing that?Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:I would say to do it, Its a lot better fix than trying to weld it.  Mac