Need HELP with cast iron

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So an antique cast iron sign holder got dropped off at my shop today for repair.   It was much bigger than what I had imagined.  I'm guessing it weighs about 700lbs , they said it takes 6 guys to move it.  It apparently fell over and broke into 3 pieces.  The sign holderAttachment 872281One breakAttachment 872291The other 2 breaksAttachment 872301My issue is that I've only ever read about welding cast iron and never actually welded it.  This is an antique from Argentina, thankfully the owner doesn't care what it looks like so long as it's one piece instead of 3. My thoughts were to drill holes and place some 3/8" pins at the two big breaks to add some structural support.   Grind it out and weld it with some nickel rod, short runs and peening it and letting it cool between runs.  Not sure if preheating or cool welding is better for this.  I honestly have no clue, but we all got to learn some time and I guess I'm going to learn with this.  Any help is much appreciated!
Reply:Getting an Invalid Attachment message on the pictures.
Reply:Get a UTP(United Technologies) book on their rods and read it. Every thing you need to know is there. They are the world experts on cast iron. I would use UTP 85FN myself. If it's been broke for long, your first and maybe second pass will bring out a lot of impurities in the form of pin holeing. Just partially grind them out and weld over.
Reply:I couldn't view the images but brazing may be a good option.
Reply:Sorry about that, see if this works...Last edited by Going nowhere; 10-13-2014 at 10:07 PM.Reason: Pics
Reply:May "The Force" be with you!Lincoln Electric:Ranger GXT 250SA-200LN-25Pro MiG 256Pro Mig 180Esab CV 251Invertec 160Victor Torches”
Reply:I wasn't sure if brazing would be enough to to hold this thing together.   It's getting shipped to LA in a few weeks so I want it to be able to survive the trip.
Reply:Wow that's a big hunk of cast. I think pinning it is a good thing. Will there be much stress on this thing. I would braze it. Welding that much cross section would be pretty difficult with the way that heavy cast will pull away the heat.
Reply:I have no idea how much stress they will put on it, but this thing seriously weighs a lot!  Took 3 of us to move each piece and my back is killing me.  I don't want it to break and crush anyone.  It's going to take a lot of work and I know it's probably the worst piece to try and learn cast welding on but I'm going to try.
Reply:I think you will want those two big breaks to contract equally as you weld them. As in... Fit it up, weld a little on one break, weld a little on the other. If you were to fit it up and go to town welding one at a time, you may hear the dreaded "PING" in a whole new spot that wasn't cracked before. I would TIG weld that if it were mine. Nickel 61 tig wire is excellent for cast iron.IAMAW Local 330Airco 300 AC/DC HeliwelderAirco Dip-Pak 200 with Profax spool gunPowr-Kraft AC225Everlast PowerArc 200stBuffalo Forge No.21 drill pressSpeedglas 9100xxAirco, Oxweld, Purox, Victor torchesLincoln Ranger 8
Reply:Just an idea from a physics perspective that may or may not work with differences in metal. If it's 4" on the flat and looks like about 2" on the deep, since it's already in 3-pieces, why don't you use a horizontal bore to drill a 3" deep, 3/8" hole into two adjoining pieces and insert a 6" x 5/8" rod 3" into each piece to take the stress off of whatever weld you do get to hold. That'll take the stress of the shear forces off the weld and transmit it to the cross sectional strength of the support rod. Then you join the two ends and weld the seam.Last edited by jlames; 10-13-2014 at 10:51 PM.
Reply:It looks to be flat on the back side.  Can you build a frame out of say 3/8" x 3 1/3" flat stock and bolt it to the back side.  Drill and tap blind holes in the cast and use flat head socket head screws to hold the two parts together.  That is a thick weld.  Maybe not weld it at all or just the little part on top.DanLast edited by DanD78; 10-14-2014 at 03:59 AM.Manipulator Of Metal
Reply:I'm curious to see how this turns out, I like the idea of Dan's backside frame, then you just need a big enough bonfire to pre-heat that sucker.SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:Id pin it with dowel pins if you have the equipment to get them lined up.Then id clamp that dude to the biggest nastiest flat steel table you could find.Braze away....Leave clamped over night on table covered in sand or multiple welding blankets.Remove and hope for the best.Miller Dynasty 200DXMiller Spectrum 250DMiller Millermatic 200Bunch of old blue dinosaurs....
Reply:Uhhhhhhhhhhhh......I'll bet that's some rudimentary cast that will respond poorly to heat or weld. Think window sash weights. So I'd say welding is out, leaving it for brazing.Pinning won't be easy, but IF it could be drilled and pinned with perfect alignment that would help greatly... because, to get a good bond with braze the fractured ends (four of 'em) will have to be "buttered" ok "tinned"  and that will take away the fractures' natural  peakNvalley alignment guide.As to heat input, I think it'd require two, if not three, torches working together. All with operators who have a feel for brazing. Maybe even a "hot box" or flimprovised furnace of some sort. After the ends had been tinned the alignment pins would be started and some sort of weight or  tensioned clamp method would need to be employed to keep drawing the parts together as the "tin" is brought to melt. You might "carbide" a "trough" for adding  filler at each fracture. That would be mostly so that from the flow you'd know for sure that the braze has completely gone to melt and will be making a strong bond.With all that said, it could be done, but I sure wouldn't recommend it for a first-time braze job. For practice, first, smash a cast iron exhaust manifold and see how fixing that goes before deciding to tackle the big one.Good LuckLast edited by denrep; 10-14-2014 at 09:20 AM.
Reply:Originally Posted by Going nowhereI wasn't sure if brazing would be enough to to hold this thing together.   It's getting shipped to LA in a few weeks so I want it to be able to survive the trip.
Reply:Originally Posted by denrepUhhhhhhhhhhhh......I'll bet that's some rudimentary cast that will respond poorly to heat or weld. Think window sash weights. So I'd say welding is out, leaving it for brazing.Pinning won't be easy, but IF it could be drilled and pinned with perfect alignment that would help greatly... because, to get a good bond with braze the fractured ends (four of 'em) will have to be "buttered" ok "tinned"  and that will take away the fractures' natural  peakNvalley alignment guide.As to heat input, I think it'd require two, if not three, torches working together. All with operators who have a feel for brazing. Maybe even a "hot box" or flimprovised furnace of some sort. After the ends had been tinned the alignment pins would be started and some sort of weight or  tensioned clamp method would need to be employed to keep drawing the parts together as the "tin" is brought to melt. You might "carbide" a "trough" for adding  filler at each fracture. That would be mostly so that from the flow you'd know for sure that the braze has completely gone to melt and will be making a strong bond.I believe it could be done, but I sure wouldn't recommend it for a first-time braze job. For practice, first, smash a cast iron exhaust manifold and see how fixing that goes.Good Luck
Reply:Yah Irish, I was getting weary just thinking about it. Probably the most practical fix would be to incorporate some well-thought-out signboard into the design, then it could become the main structural elephant, with the cast frame becoming mostly decorative, whereby some minimal repairs to the fractures will do.Plus it would add a much needed couple few hundred pounds to this flimsy thing.
Reply:I have to agree with Irish and denrep that it's probably not a good job for a beginner.   If I was going to take a run at brazing that I think the first thing I'd do is find out just how much the customer would be comfortable with spending to get it fixed.   Because I could for see easily having 10 to 12 hard, hot hours in that.   If you think it's hard to handle the individual pieces when it's cold just wait till you get it all up around 900 F. and need to flip it over (gently) as a solid unit.Last edited by HT2-4956; 10-14-2014 at 10:29 AM.
Reply:I see it laying on a flat table with the pieces propped up as necessary to get every thing lined up good with the weld prep made about 1/2 to 2/3 down into it.  That way the bottom, remaining un-prepped portion will act as an alignment guide.  Then building a temporary tunnel around it with some fire brick and using several weed burners to bring it all up evenly to around 900 -1000 degrees.   Then opening up the bricks in just the area where I was going to be working.  You'd probably need to go around and get a little braze on each broke area before you went to filling any one spot up just to insure nothing moved out of alignment on you.   Then it would be a matter of flipping it over, making your prep on that side, putting the fire brick back around it, bringing it back up to temp and doing that side.    All the time you were working in one area you'd probably have to have a weed burner or two running on low opposite you just to keep heat in it.   Because until you get the table top warm it's going to be sucking heat out of the piece.I'm talking about doing some thing like this  for getting the part hot.
Reply:I just REALLY want to hear how it turns out when you tackle it and how you tackled it.
Reply:An old 1930's book, they took large machine bases and pinned them all over before welding. I have no advice on this one! Definitely agree on the brick oven idea, if you do decide to try it. Good Luck!
Reply:Thanks for all the replies.   I've got about a week before starting in on it so keep any suggestions coming.  Unfortunately this is a Double sided sign so both sides look alike and have the twisted rope design so not sure a support frame would work, but if it were flat on one side I would definitely consider that.It measures 73" tall and 69" wide if that matters.Here are a few more pics for scale.
Reply:Getting it sand blasted to get all that paint off first would be a good idea.   Other wise you'll be breathing all those burning paint fumes when you first get it hot (and that could be lead based paint). A grinder leaves a layer of smeared carbon platelets on the surface.  That will interfere big time with the brazing alloy forming a good solid state bond with the parent metal.   You can use a grinder to rough in your prep but be sure and go back over it with a carbide burr and cut the ground surface layer off.  Once it's up close to temperature set your torch with a highly oxidizing flame and sear the faying surfaces with it.   This will help to burn off / out some more of the carbon at the surface.   This will help insure you get a good bond.   Once you've got that done adjust back to a neutral flame before you start trying to add brazing alloy.
Reply:WOW!!!!I am not much of a cast iron guy, but if it was me I would start by beveling all the edges, then pinning the broken joints, pre heat like crazy and try to tig weld with silicon-bronze. (Silicon bronze just seems to flow better for me). Last I would cover with sand so it cools as slowly as possible. Good luck!Update.So I've decided to pin and braze it because that's what I'm most comfortable with.  I used 1/2" round bar on the bottom and a 3/8" diagonal rod and 3/8" on top with 1/4" opposing rods to prevent it from pulling apart.   I'm going to trim the rods flush and braze them in as well.  The small decorative piece will just be brazed without pins.  I'm just going to bury it in sand and pray.Attachment 887801Attachment 887811I'll keep you updated when it fails in an amazingly catastrophic manner!
Reply:I finished this project awhile ago, just now updating for those that were curious. I actually tried welding it with horrible results.   There was a lot of porosity and too much temperature shock which lead to cracking.   It soaked heat up like nobody's business. Bad welding.  It got ground back out and brazed. Brazed and blendedPrimed and ready to go.Hope this is helpful to someone out there.   I had zero experience with cast iron repair and it was a challenge but it turned out great and held strong.
Reply:Looks good from where I'm at.
Reply:That looks great, GN! Good job.What type of torch(es) were utilized?Fuel? Tips? Position? Handling?
Reply:Thanks guys.  I wasn't super optimistic when I started but that's just how I am.  I'm a one man shop with occasional help from my wood working buddy.  Definitely would have helped to have extra hands but I made do.Had a Harris O/A setup with pretty fresh tanks.  I used the cutting torch because it provided better heating than a welding tip.  Bought a weed torch (flame thrower) which really throws out some heat.  Also had a couple little propane/mapp torches.I built a little furnace out of sand and slowly heated the area to about 800f when trying to weld it and about 400 - 500 when brazing.   Used a quality infared thermometer to constantly check heat.  I kept heat on it at all times and then buried it all in sand.I destroyed a good pair of leather gloves from the heat and it was pretty uncomfortable but I worked fast and had a lot of half used rods.
Reply:Flux coated rod?Nice job!SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:GN,Way to go man.  Good job.   How many hours did you have in it?
Reply:Originally Posted by Going nowhereI destroyed a good pair of leather gloves from the heat and it was pretty uncomfortable but I worked fast and had a lot of half used rods.
Reply:That thing scares me just looking at it....It reminds me of old exhaust manifolds looking at the grain in it ...Best of luck to youBacked my CATMA over your CARMA oops clusmy me  What would SATAN do ?? Miller Trailblazer 302 AirPakMiller Digital Elite  Optrel Welding HatArcair K4000Suitcase 12RC / 12 VSHypertherm PM-45Rage 3 sawRusty old Truck
Reply:Thanks for the update! Nice repair job!12v battery, jumper cables, and a 6013.I only have a facebook page. https://www.facebook.com/pages/VPT/244788508917829