How To Weld Cast Iron

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I have this old concrete mixer that just broke the cast iron 'bearing' thing. I wonder if I - a novice, novice, clumsy, stupid welder, should attempt to fix it? I have the vague idea that welding cast iron is difficult - or there's many types or something. Anyway, here's the job, I'll appreciate any thoughts on the subject:  mmm.... that image insert didn't work when I looked at this after posting. So I'll post the direct link to the pics on photobucket here:http://s307.photobucket.com/albums/n...crete%20mixer/Last edited by abrogard; 09-20-2011 at 06:37 PM.
Reply:Great looking mixer.  I think my Dad had one just like that when I was a kid.  He used that old mixer a lot back then and couldn't of done without it. Cast can be welded I'm sure, but in my nearly 35 years experience of welding for living I can say that cast is a difficult metal to weld. lol.  It will crack as it cools off as the weld metal draws up.Way back when a boss I once had told a guy with a cracked engine block "I can fix that".  After he turned a 3" long crack into a 12" long crack about 4" wide he told the guy it couldn't be fixed.    Well, the truth was - it couldn't be fixed NOW!!!!   Him and his cast rods messed up this guys block.  One time back around 1992 a local farmer friend of mine dropped by with 2 old broken cheap cast vices.  He said, you fix them and I'll give you one.  When I had time I welded both vices then called him up.  He came by and ask me to pick which one I wanted.  I told him to pic.  I still have that old repaired vice and I've even had it on my rig trucks all this time since that day.  I've hauled this old vice around all these years and it is a conversation piece (probably why I still have it) and I've had it all over the country.  And it still works and I do use it whenever I need a vice.I found this out many years ago about welding cast while trying to fix a bellhousing which had be broken into 7 pieces for a company I was hired out to at the time.  Use LoHi 7018 rods and weld an inch at a time, chip it, then brush it, when weld an inch again.  With that technique I fixed that bellhousing that day and it was on a 871 Detroit V8 diesel compressor engine.  I used that same inch technique any time I haft to weld cast and it has always works for me every time,  and those welds will hold I have no doubts.If I weld more than that 1" the metal gets too hot and will crack.  Same for less.  If I don't get into the right rhythm of chipping and brushing it cools too much or doesn't cool enough and will crack.  But with the right timing I can put on huge lohi 7018 welds on cast without any cracking. Just a thought.Good luck man, and enjoy the mixer.  Those were good ones for sure.{edit}  Just ran out to the truck and took a couple pics of that old vice,  18 years after the fix.   And yes, that was 1/8" LoHi 7018 rods welded with a 1980 SA200 on probably 150 and 45 (if I could remember that is   (all the 7018 I had laying around in the garage at the time). Attached ImagesLast edited by slowhand; 09-20-2011 at 07:51 PM.
Reply:wow, that old relic brings back memories! - the mixer, not the vice.ɹǝʌo ǝɯ lloɹ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı
Reply:Wow Slowhand, Im gonna remember that one trick. I remember in school last year when we first learned about 7018s for the first time, the teacher mentioning that they could weld *some*cast.Thanks for sharin, man [Account Abandoned 8/8/16 Please Do Not Attempt Contact Or Expect A Reply]. See you on YouTube! -ChuckE2009
Reply:Yes, thanks a lot for that post. It was great. Wouldn't it be good if all forum posts were that good? We've never stop reading forums......Well I've given the job  to local professionals....  you make me think they well may screw it up themselves, it's so hard, potentially - who knows what cast iron mix it was when that mixer was built.But if they screw it up they can quickly fabricate me something to do the same job out of whatever they like that's strong enough.  It is not really a bearing, is it. Just a retaining hole or something.The 'yoke' of the mixer turns 180 degrees in it when pouring, then comes back and that's all 'till the next load. Should be easy to make something to handle that workload. I'll try a bit of cast iron welding when I find a bit of cast iron. Try and chase up those rods you mention. Don't know how many USA rods we can get here in Aus.
Reply:http://www.lincolnelectric.ca/knowle...ronpreheat.asphttp://www.lincolnelectric.ca/knowle...rackrepair.asphttp://www.lincolnelectric.ca/knowle...electrodes.aspHmm, just noticed that I was somehow on the Canadian Lincoln website.  Eh.    Not that it really makes any difference.Two main ways to weld cast iron, as mentioned in the fiirst link above.  Hot, or cool.  I lean more towards the 'Do it Hot' school of thought.  And the 'classic' welding filler/rod for welding on cast iron is a nickel rod.  Nickel filler doesn't really have 'issues' with all the carbon in cast iron, bit it is DarnExpensive.  Although other fillers/rods might be used, you run a very-very-very high chance of ending up with some very-very-very hard and brittle weld (due to the high carbon content of the cast iron mixing with the steel filler and ending up with a very-very-very hard and brittle martensitic weld bead that cracks or the contracting/cooling weld bead pulls the brittle cast iron apart and PING! upon cooling after the weld).  The best laid schemes ... Gang oft agley ...
Reply:You could braze that piece back together with an O/A torch and some brazing rod.  I brazed a vice sliding jaw back together way back when I was a teenager and just learning to weld.  That vice is still in use today, 40 years later."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Think they hit the critical stuff.But you must also have a good quality probably grey casting to start with. Crap stuff ain't going to weld. Cut a vee down into it to expose good metal if possible, surface weld ain't going to do much depending on the part. The impurities move out to the surface areas in the casting process.I used to do it on a wood stove. Jig up the parts on the stove top, fire it up good and hot. Let it get good and preheated, I used the rods listed as for welding cast from Harbor Freight, they worked.Once welded, I left it on the stove with a good fire that burned out. After everything cooled down, then it was removed. Did some pretty thin stuff that way.Had a neighbor that was the chief tool and die maker at a company that did powered metals. They had cast parts used in production dies that would break. They always brazed them. Apparently that is the preferred way of getting a fix.
Reply:I welded the cracked wheel for my bandsaw recently ...threw it in the kitchen oven turned all the way up for a while, welded it with some stick electrodes made by hobart called normacast that i bought at a hardware store..Immediately threw it back in the oven after welding, turning the temp down a little bit every 20 mins or so..It worked this time
Reply:Very interesting these posts, I think.    What happened with my job? He brazed it. Very coincidental, eh?  Here's the pics:  And here's the URL again, like last time, lest the 'insert image' thing doesn't work again. http://s307.photobucket.com/albums/n...crete%20mixer/