Welding Cast Iron

[StrawHat]

I have a piece of cast iron for a hand plane I need to extend approximately 1/4".

Can it be welded? Brazing may not work so I thought I'd ask about welding. Seem to recall that cast iron is a pain to weld.

Thanks

[docone31]

Brazing is the trick.
Years ago, when I worked in a garage specializing in foreign cars, when a manifold would crack we brazed it. We could also braze on parts that snapped off.
The trick is to keep the heat constant. SLOWLY let it cool.
There is cast iron rod for the electric welders also. I have no experience with that though.

[yarro]

If I remember correctly from by welding class 20 years ago, you have evenly heat up cast iron to a specific temp before you weld on it. Brazing is much easier to deal with.

-yarro

[454PB]

Brazing works fine and is easy to do, but cast iron can be arc welded using the correct rod, and preheating.

[Uncle R.]

Ditto the brazing. As strong as the iron itself and much easier to do than welding. Heat the part uniformly, cool slowly. On a rough casting I'll usually grind a small bevel on the joint to get clean metal before I begin heating.
Uncle R.

[JIMinPHX]

It sounds like the pre-heating & slow cooling part has already been covered. You need that regardless of which joining method you choose to use.

If you are going to arc weld cast iron, then you need NiRod (nickel). The stick rods usually have a black flux on them. It ain't easy to work with, but it can be done. If you want to go that route, then I recommend that you find someone that's done it before (& had good results). Let them do it. Figuring it out the first time is no 5-minute job.

The better way to join cast iron is with a TIG machine & Silicone Bronze rod. You can do cast to cast, or cast to mild steel easily with that method. The joint is even freely machinable & easy to work with later, which I can't really say for a NiRod weld. I've had good results using Silicone Bronze & a TIG on everything from tool holders in a CNC machine to heads on a 73 Harley Sportster. It's the way to go if you have a TIG machine available.

It's also possible to braze with an oxy-acetylene torch, but I'm not sure of the proper rod for that. I haven't done it that way myself.

[45caster]

It sounds like to me this piece that you want you weld would be better off brazed . I have brazed some pretty heavy carbon pieces to cast iron . Best thing to is bevel your joints tack them braze them together . You need to preheat and post heat if possible good luck

[shotman]

For what you need to do brass is the best you can work it easy to get what you need. Nirod is for something you dont need to work down. Also Ni Rod is not cheap

[Bret4207]

I'd recommend coating the plane with anti scale compound to keep the "uglies" to a minimum. Brazing, done right, should be the ticket.

A little OT- I once welded the 3 pt hitch attachment for a JD 40 crawler. This is a casting weighing about 170 pounds. Had a lovely diagonal crack running the length of it. I vee'd it out on both sides and clamped thing together with a Rube Goldberg collection of chain, Vise-Grips, C clamps, some strapping and bubble gum. I spent my childrens inheritance on Ni-rod and positioned my 3 burner Magic Chef travel trailer stove under the casting and preheated til the casting was running 200+ F. Took me days to weld it. Weld and peen, weld and peen, weld and peen then grind and chip. I think I spent a week total. Of course as soon as I got done an old timer stopped by and said he'd done the same thing and found brazing worked much better! Ah, I learned anyway.

[JSH]

Ditto to what Jim said. If this for a hand plane for wood and you are going to plane anything that is much count. I would guess you would wnat the planning surface nice and smooth.
I am no welding exspurt, but have burned a stick or two of rod and and my fair share of wire. Any exhaust manifold I ever saw welded with brazing rod broke sooner or later. If you braze or nickle, tig will be out down the road, short of cutting enough material out to get the brass or nickle out of the pores of the metal.
Some guys I have known in the past to brag on how well the can weld cast iron were, actually welding cast steel. Close to the same but it is different.
Welding true cast iron ranks right there with trying to weld cast alum. Stuff is so porous that you have to watch what you grind or clean it with, let alone get to clean metal.
As one old guy that used to weld a lot of cast steel racing heads told me, treat it like you are soldering and you will be fine.
I think I would just buy a longer plane as you have a high chance of ruining the one you have.
jeff

[DLCTEX]

I have welded lots of cast iron with mild steel rod. You have to heat the cast to a dull red, weld while it is red or reheat to keep it red, then cover and allow to cool slowly. I had a gas forge in our shop that was used to heat the iron, then the fire was turned off and the welding was quickly done, then the piece was reheated, covered, and allowed to cool. I did split exhaust manifolds for six cylinder engines. A chevy six split 4-2 with glass packs would really talk! I had read in Hot Rod magazine about using the process to weld cylinder heads for increased compression ratio and adapted it . Prior to that I had used brazing, but it would give way under the heat of running the engine. Couldn't get engine blocks hot enough, so I used Ni-rod for cracked blocks. Weld about 1/4 inch then hammer the weld till it cooled, then weld again.

[theperfessor]

I think the right method would depend on whether you were building up your extension with the added material or joining two pieces together. If you are joining two pieces together I would think that brazing would be the way to go. If you are building up the extension with your added material I would consider using a nickel rod.

Your wood plane probably is not soaked with oil and won't be used under high temperatures. Cast iron (not steel) is porous and will soak up oil. No matter which method you use when you heat it up the oil vaporizes and will keep you from making a solid joint. I have been involved with repairs where the joint was welded and chipped out several times just to remove the oil and to get down to solid weldable material.

Using brazing to join two pieces together would give you a strong and nearly invisible joint. I own several old block planes, both wood and metal. The metal ones are all painted, so assuming yours is similar a little matching paint on everything but the bottom would make the joint nearly invisible.

One time years ago I welded together all the broken pieces of a couple cast iron fence posts that had been damaged by a drunken driver's car for a homeowner in a historical preservation area. I used nickel rod, pre-heated and post-heated it, and dressed off the seam. After repainting it you would be hard pressed to know it had been damaged.

I also repaired a cast iron windmill pump that was cracked and had to have some worn areas built up for new bearings. Used nickel rod on this also, again with pre- and post-heating. The surface was ground to match the contours and the bores machined like butter.

The main problem with welding cast iron is that cast iron is brittle and has a lot of free carbon. Nickel will not hold much carbon in solution. Steel is just iron and carbon in solution; iron will hold up to 1.7%, any higher carbon content will turn steel into cast iron with free carbon in the form of balls, flakes, or graphite clumps. As nickel cools the carbon it picks up from the cast iron is squeezed out, which expands the joint, relieving a lot of the shrinking stresses that come from cooling. But it leaves a lot of carbon adjacent to the weld area, which causes brittleness (untempered martensite) if post-heating isn't performed to redistribute the carbon evenly back into the base metal.

I might note that nickel rod is so expensive that the local weld shop supplier sells it by the rod and not the pound, but it doesn't sound like you'd need that much if you decide to do a build-up weld.

If you choose this route, spend a lot of time in all your prep work. I make build-up extension welds (as opposed to build-up pad welds) by putting brass backing plates around the area to prevent a lot of extra weld material from slopping over into areas where it will just have to be removed anyway. Clamp the brass plates to shims so that you get some extra material, to be removed when you take the material down to finished size. Pre- and post-heat as necessary. And take your time.

[softpoint]

Hey, We are touching on what I do for a living for 35 years! If I were you, I'd try brazing. I finally got to the point that I turned down most cast iron welding jobs. Most cast isn't made to any particular specification, and I couldn't guarantee my customer a succesful outcome before the job was started, and some cast iron is unweldable. Now, since you are doing it yourself, and only have yourself to please, thats fine. If you do choose to weld it, either use the soft 90 to 95%nickel rods,there is another, cheaper rod that is a lot harder(and harder to work with) I'd stay away from it ,I think, for what you are doing. There are also some "cold" cast iron welding rods that require no preheat and are probably the best of all. There is also a good chance that what you are working on isn't worth very many of them. We use very few of those even on oilfield equipment here because of cost. Only a few specialty companies make them, and if you decide you want some,awelding supply house should be able to get you some of the brand they sell. Having said all that, I still think I'd try brazing with brass and flux!!:-D:drinks:

[grumpy one]

A couple of simple points. First, never grind a cast iron surface that you intend to weld or braze. File it or machine it. Grinding smears the graphite flakes over the whole surface and the resulting coating is then pretty much not removable. Second, the process you need depends on what you are going to use the finished object for. My experience suggests you should forget the idea of repairing automotive exhaust manifolds if they are to be run at full throttle - the manifold runs red-hot for extended periods, so brazing breaks down and there are metallurgical problems at the boundaries of arc welds. Nodular iron manifolds MIG-welded with special filler materials will work for a while, but essentially the thermal stresses are quite unreasonable and you get hot tears in the parent material if you don't get weld cracks. Beyond that, how difficult stick welding cast iron is, depends on how much you care whether it breaks afterward. I've had 100% failure using mild steel general purpose rods, no matter what procedure I used. I've had 100% success using name-brand rods made specifically for cast iron, provided I had a good quality, totally clean casting and a freshly-machined surface to weld, I followed the rod instructions precisely, I made the weld joint three times as thick as the parent metal, and I ran the weld out about five metal-thicknesses around the joint.

I once had a side-valve cylinder block for a very old car that I was modifying for increased power, so I had the cylinders bored out until they got porous and cloudy due to approaching the water jacket, and I milled out the intake ports until they were way into the water jacket. Then I took the resulting mess to a specialized welding firm. When it came back I assembled the engine and my family ran it for years, including some racing. No problems whatever. However I am completely confident that I could not have matched whatever they did. I know at least some of my limitations.

[softpoint]

That's the key,GrumpyOne, The quality of the cast iron has everything to do with it. Thats is why I quit taking on cast jobs. It's hard to charge people money if you can't guarantee your work.

[StrawHat]

Thank everyone, for the replies. I am not a welder and thought it was a difficult job.

I don't have a photo but the part I need to lengthen is the "Y" shaped piece that allows the iron to extend or retract through the sole of the plane. From what you are all saying, it might be easier for me to just fabricate a new one from solid stock. The plane was made by the Ohio Tool Company, long out of business and parts are hard to come by.

Thank you again for all the tips.

[Bret4207]

Ah! You aren't talking about the plane itself, but the yoke thingee. If yours works like a Stanley/Bailey pattern there's enough pressure on that that I wouldn't try messing with it with weld. Making a new one might be an option or get a different iron for the plane. Seems to me some of the "Fine Woodworking" type specialty makers offer blanks, Bridge City maybe?

[wallenba]

Freind of mine had a break in his 8n tractor block welded, so I know it can be done, call around some farm implement dealers.

[theperfessor]

If it's worth fixing you might be better off having a new piece made. Then you can always put the old piece back in place, unaltered, if you decide to put it on display or sell it to a collector.

Personally, I would not mess with the old piece.

[StrawHat]

Not messing with it means I can't use it. As a carpenter and woodworker, I don't have space for anything I don't use, so I will create a new piece.

Bret4207, thanks for the tip about Bridge City. I will check if they have something I can use. If I can't make it myself, I will order one.

Thanks for all the ideas about welding. That is one of the arts I am least familiar with.

[jwhite]

I have had really good luck with MG 200 TIG rod for cast iron, expensive but well worth it. Have welded everything from an engine block in a skidder to a small antique spoke shave with it. TIG is the way to go for cast iron, pre-heat, post-heat and take your time.
JW

[oldtoolsniper]

Shoot a pm to me with the type as in size #3, 4, 5, 6, etc and the color of the japanning and tote color. Does it say Ohio tool on the blade or the plane body? If it says Made in USA it’s fairly new. Is there a patent date on the body or casting? The part you are referring to is called the frog. I have 300 to 400 planes sitting around here; I may have the part you need. A picture would be the most useful. That is a very common break as well as cracking at the mouth. If you weld or braze it they become parts planes to me and at most a user plane.




Not messing with it means I can't use it. As a carpenter and woodworker, I don't have space for anything I don't use, so I will create a new piece.

Bret4207, thanks for the tip about Bridge City. I will check if they have something I can use. If I can't make it myself, I will order one.

Thanks for all the ideas about welding. That is one of the arts I am least familiar with.

[Bret4207]

I thought the frog was the base piece for the iron and adjustment parts? I think he's talking about the yoke that slides the iron forward into the mouth.

[oldtoolsniper]

I thought the frog was the base piece for the iron and adjustment parts? I think he's talking about the yoke that slides the iron forward into the mouth.

Go here and look at the diagram 1/3 of the way down. Item # 6

http://www.supertool.com/StanleyBG/stan1.htm

[StrawHat]

Shoot a pm to me with the type as in size #3, 4, 5, 6, etc and the color of the japanning and tote color. Does it say Ohio tool on the blade or the plane body? If it says Made in USA it’s fairly new. Is there a patent date on the body or casting? The part you are referring to is called the frog. I have 300 to 400 planes sitting around here; I may have the part you need. A picture would be the most useful. That is a very common break as well as cracking at the mouth. If you weld or braze it they become parts planes to me and at most a user plane.

On Leach's page it would correspond to Stanleys part #7, the "Y" adjusting lever.

OTS, I am sending a PM so the rest of the guys won't be bored reading about old planes instead of cast boolits!

[Freightman]

I was kinda looking forward to seeing it myself

[StrawHat]

I was kinda looking forward to seeing it myself

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[wilddog45]

I have had success welding cast with a wire welder.