Need suggestions repairing cast iron bench

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Hey guys. I got a cast iron bench that needs repaired and looking for a few suggestions for those of you with more cast iron experience. I know normally one would pre heat the piece to 800 F or so and then weld with a nickle rod or tig some aluminum bronze etc. but I cant pre heat this piece. Its too large to feasibly preheat.   Here's the photos.   Just looking for suggestions on what to do. nickle 99 rod? Tig aluminum bronze? Braze?      I would be doing this without a preheat.   First pic is the small piece will be welded back onto the leg. Next pic is what will look like when the leg is welded on to the bench itself (looking at the underside of the bench) Dynasty 200DX   (2014)Millermatic 211 (2015)Optrel 864   (2014)Smith Medium duty MBA 30510 (Xmas 2014)Tennsmith 16ga 4ft finger brake (2015)Trailblazer 325 EFI and excel Thermal dynamics Cutmaster 82Miller maxtron 450
Reply:I would torch braze it
Reply:You could probably get away with a localized pre-heat and a nickel filler. But I'd be tempted to just braze it since I had the torch out to pre-heat it anyway.Lincolin Power Wave 450, Lincoln Powermig 255, Lincoln Pro Mig 140, Lincoln Squarewave Tig 275, Miller Big 40 G(with Hobart Hefty suitcase), Thermal Arc 95S and Esab PCM875 in an already full machine shop.
Reply:I would think brazing.Forney C5 Arc WelderLincoln Idealarc 250-250 Ac/Dc Arc WelderMiller Bobcat 225g PlusLincoln PowerMig 200Forney O/A Rig
Reply:I'd braze that. But then again, all I have is a O/A welder so my only options would be brazing or welding with cast iron filler. When all you have is a hammer, every problem looks like a nail...
Reply:I would tig braze it with aluminum bronze (a2).   would also preheat.   and throw blanket over it
Reply:oxy acet brazei.u.o.e. # 15queens, ny and sunny fla
Reply:Alright well I'm cool brazing as I won't have to go out to the lws and buy some aluminum bronze but is a localized preheat okay?? I mean this thing is too large to preheat for me and with all the paint on it, that crap would be no good preheating....  Even though the leg is small enough to do a full pre/post heat I cant really do it with the paint on it.Last edited by outdoort; 04-27-2016 at 09:00 PM.Dynasty 200DX   (2014)Millermatic 211 (2015)Optrel 864   (2014)Smith Medium duty MBA 30510 (Xmas 2014)Tennsmith 16ga 4ft finger brake (2015)Trailblazer 325 EFI and excel Thermal dynamics Cutmaster 82Miller maxtron 450
Reply:Clean area to be brazed of paint then heat and braze
Reply:Well, I brazed the thing together but after the fact wished I went and bought some nickle 99 rod.  The paint in the localized areas kept catching on fire  from the flame.    But thanks for the advice everyone, job is complete!Dynasty 200DX   (2014)Millermatic 211 (2015)Optrel 864   (2014)Smith Medium duty MBA 30510 (Xmas 2014)Tennsmith 16ga 4ft finger brake (2015)Trailblazer 325 EFI and excel Thermal dynamics Cutmaster 82Miller maxtron 450
Reply:Pix!Lets see dem welds... er..brazing.Be wary of The Numbers: Figures don't lie,. but liars can figure.Welders:2008 Lincoln 140 GMAW&FCAW2012 HF 165 'toy' GTAW&SMAW1970's Cobbled together O/A
Reply:Alright. Heres a couple pix. I could probably use some more practice brazing, but I was pretty satisfied with how it came out. Anyone know how to prevent those pores/holes in the braze? I'm thinking its cuz I was too hot.Dynasty 200DX   (2014)Millermatic 211 (2015)Optrel 864   (2014)Smith Medium duty MBA 30510 (Xmas 2014)Tennsmith 16ga 4ft finger brake (2015)Trailblazer 325 EFI and excel Thermal dynamics Cutmaster 82Miller maxtron 450
Reply:Could be from dirty cast iron. Did you V out the cracks? It's hard to tell from the pics but wondering if you have good adhesion at the edges of the braze? Usually when it's too hot you get a lot of white smoke all around it.
Reply:Originally Posted by Bls repairI would torch braze it
Reply:Originally Posted by Welder DaveCould be from dirty cast iron. Did you V out the cracks? It's hard to tell from the pics but wondering if you have good adhesion at the edges of the braze? Usually when it's too hot you get a lot of white smoke all around it.
Reply:Nirods easy money
Reply:And you don't have the difference in color.
Reply:Originally Posted by outdoortAlright. Heres a couple pix. I could probably use some more practice brazing, but I was pretty satisfied with how it came out. Anyone know how to prevent those pores/holes in the braze? I'm thinking its cuz I was too hot...........................
Reply:Originally Posted by HT2-4956outdoort,That porosity you got is most likely due to having over heated the puddle to the point where you started to boil the zinc out of the brazing alloy.And I know this is kind of after the fact but just for future reference....concerning any grooves or bevels you make for a prep...you shouldn't try and braze to a ground surface.  Grinding leaves a layer of smeared carbon platelets on the surface of the prep that interferers with the brazing alloy forming a good solid state bond with underlying crystal structure of the cast iron.   It's OK to rough out your preps with a grinding rock but you should then either file or use a carbide burr to skim cut that ground (smeared) surface layer off before starting to braze.
Reply:Immediately after welding that piece onto the bench, bury that portion of the bench with DRY sand and let it sit overnight.That willed to keep it from cracking. Good Luck. Braze with silicon bronze or stick weld with a high nickel rod. Welding stores sell rod just for cast iron. It has a black coating.AWS certified welding inspectorAWS certified welder