TIG welding cast iron?

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I just rescued two Record vises from the scrap bin a school and decided to overhaul them. disassembly was easy and cleaning too but I found a crack on the back of the sliding part right in the casting seam (couldn't take a picture, but look at the red rine on the current picture).I was tinking about drilling the crack end and grooving  then TIG welding with stainless rod. any thoughts? could it work? and if it does, will it be OK?at least it isn't in a really crutial part of the vise but I don't want the crack to expand.I know SMAW with nickel rod would be better but I don't have SMAW stuff.thanksthe best way to hurry is to take your time.
Reply:Some cast welds better than others, just have to try it. If you are going to tig weld it 309L should work well. Most people will preheat and post heat to keep the part from cracking, but some don't and don't have problems.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:In general, it took a lot of 309 to do it last time I did it, and I did have cracking issues and had to really preheat the part, and then bury it in sand.Previously, I have used the tig torch and nickel braze rod and it worked like a charm, with no fighting whatsoever.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:I'd use 312 filler. Always worked for me.Lincoln Precision Tig 185Lincoln Power Mig 256Hypertherm PM 45Everlast 140STSmith O/A
Reply:Peter (Castweld) here has done several posts where he tig welds cast iron parts using nickel filler.I've done one or two small repairs where I used some old nickel stick rod with the flux removed for tig filler..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:thanks guys... I can't remember what stainless grade I have but I'll give it a try tomorrow with a good preheat and a really slow cool down.but eh, even if I trash it, I'll learn something from it... and it was free! I'll keep you in touch with the outcome.the best way to hurry is to take your time.
Reply:I have been testing a bit of cast iron welding on a couple of old twostroke engine cylinders, basically breaking cooling fins of and either welding them back on, welding the loose pieces together with eachother or rebuilding a missing corner.I have a Henrob O/A torch and tried filler rod for mild steel, 316 stainless TIG filler rod, and cast iron piston rings from a scrapped Briggs & Stratton lawnmower engine.Mild steel filler: Miserable failure. Filler needed alot higher temperature to melt, so I could dip it in the puddle, lift it up unharmed with a drop of molten cast on it!316: better, but really bad. Plenty of bubbles in the joint, and broke easily between the joint and the base metal.Old piston rings: Good weld, about the same hardness and colour as base metal. Very few bubbles. Broke one piece both along and across the weld, and there were no obvious weak places the crack wanted to follow - it broke where I hit it.
Reply:What about brazing with silicon bronze?
Reply:Originally Posted by KelvinWhat about brazing with silicon bronze?
Reply:Not sure which part you're talking about.  Picture?If it's steel, I'd go 309 or E70S2/6, or similar.  If it's cast iron, I'd go a suitable bronze (like aluminum Bronze A2) if color match is not important, otherwise low-expansion Nickel alloy rod designed for arc weld repairing cast iron.  309 on cast is a bad idea, IME.  You're asking for cracks along the weld boundary.I just weld repaired a vice myself successfully.  I used nickel-55 rod to repair a crack where I wanted color match, and I used Aluminum bronze A2 where I just needed to build up wearing/friction pads a bit and didn't mind the gold color.  (Seems like bronze works well for friction/sliding type applications too.)  Both applied with TIG.  I didn't do anything extraordinary with regards to pre-heating or post-cooling.  Vice is now better than new.  Hope this helps.
Reply:I ended up drilling the crack end and screwing a cap just to make sure it doesn't move.the best way to hurry is to take your time.