Cast iron repair?

admin

I have a gray cast iron 'goose egg' motor cover for my tablesaw.  It is around 15" x 15" x 8" bowl if you will.  It looks like someone dropped it and now it has a crack from the edge 2" or so in.  It is not structural, but I want to stabilize the crack so when I paint it disappears.  I have a 120v Mig, AC arc welder, and oxy/fuel rig.What I was thinking about doing was preheating it to 400 degrees or so then brazing it with flux-coated bronze brazing rod.  Does this sound like a good idea or is there a better way.I am a beginer weldor who has messed around with MiG for a while but recently took a course in oxy/fuel and arc welding.Thanks!Chris
Reply:You got it.  Braze it.Pics?David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:you could try cast iron rod but big money.... get it really hot to braze it dave right
Reply:I would braze it too. Just make sure to grind out the crack really good first.
Reply:Brazing is your best, easiest, and least expensive option. The mig wire I use for cast iron runs $40+ per/lb, and I only use it on antique casting repairs and sticking cast iron to mild steel in cases where I can't braze.The difference between art and craft is the quality of the workmanship. I am an artist.
Reply:What MiG wire do you use for cast iron?  How many amps do you need?  Preheat as well?Chris
Reply:I use .045 Allstate CoreCast 8600, needs 98%Ar 2% O2, DCEP and lots of amps. A promig 155 will run it on max, but not for very long. Using the feeder and my engine drive (400 amp machine) I run it about 200 amps or so (not sure because no meters or numbers on it) this is on feathered thin castings, heavier castings need more heat. I preheat until it turns blue, then weld it and post heat it to red and let it air cool (ambient air temp over 80 degrees) I won't even try it under 70 degrees unless I can bring it in to the shop where I have a little better control over cooling. I only use this stuff when brazing would be difficult (horizontal and hard to get to) otherwise I braze it. Takes a little bit longer, but costs a lot less. I've never seen it in spools smaller than 10lbs (over 400 bucks) and that is several months ago. There are other cheaper wires available. This stuff is fantastic for sticking cast iron to steel (that's what I got it for) and turns out it works real well on these old castings. My business partners brother has used it for about 20 years now for building up crankshafts for natural gas compressors.The difference between art and craft is the quality of the workmanship. I am an artist.