Fixing cast iron part

My neighbor called me this evening about welding a cast part on the steering mechanism of his tractor. It was dark, so I haven't been able to go out and
look at it. I shall look at it on my way out tomorrow on my way to Vegas. He's going to check on the cost and availability of the part tomorrow, also, then Friday, we'll pow wow and decide to try to fix or get a new one.
I have welded cast before, but never correctly. What I welded were dissimilar metals, as in spindle tops on ornamental metal, which cracked off easily when he kids hit them with sticks, or I bumped them during installation I have never preheated, welded with Ni rod, and post heated.
I believe that if I clean this part, grind bevel the surfaces to get good root penetration, preheat correctly, then postheat correctly, clamp to allow for warpage, that I have a good chance of fixing it. How long it holds is another matter.
Any pointers on: root prep, preheating temperature and length of time, arc technique including length of arc, comparing this rod to any other rod that may burn similarly, postheating and length of time. Is there any benefit of gussetting the area for additional strength? What specific rod should I get? How do I match rod diameter to work piece thickness? I have a laser temperature gauge, but I believe this will be beyond the parameters of that sensor. What temperature Tempilstick should I get?
I'll know more tomorrow when I see it, and will post a pic so you can have an idea. He says the part is relatively easy to remove, and that would give me the ability to clamp it on the bench and weld it in the flat position.
This will be a first for me, and a big deal if I can save my friend some time and/or money. He's a great neighbor, and does tractor work for me for fuel costs.
I do have some gas welding tips, and would this part be better gas welded than arc? If I do that, what Ni filler rod should I get? Or can I get electric rod, and use it for both types of repairs. A little voice tells me no, but I'll ask anyway.
In the meantime, I can use just hypothetical advice until I get the pictures, and a little better handle on this. If I can get all the info pulled together, it looks like doing the actual welding Friday or Saturday. Quick replies appreciated, as I'm going to pull the trigger on this Friday or Saturday.
And is there any such thing as putting down the first pass the first day, letting it cool overnight, buffing it, and then putting a beefy cover pass the second day?
TIA
Steve
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Clean clean clean

No specific time, but at least 500 degF, but 800 is better.

A relatively short arc. Low amps, stitch areas, then stop and peen the weld to stretch it as it cools. You want to apply the nickel to the surface, NOT mix it with the cast iron. You don't want dissolution into the base metal.

Nickel rods are their own creature.

Slow cooling is critical. like 100 degF per hour.
Burying the part in powdered lime works well, now that vermiculite is banned. (damn you EPA)

Have to see what the structure is.

The 55% nickel rods are more machinable, but the 75% or higher rods are a bit stronger.

3/32" rod for 1/4" or thinner, 1/8" rod for everything heavier.

Something in the 600 - 800 degF range.

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wrote:

Unless it's your state law, vermiculite isn't banned, Ernie. EPA never banned it. It's available from a garden shop near me in NJ.
None of the Libby Mine vermiculite is on the market anymore (it was closed in 1990), and the EPA says that their samples from other parts of the country and from foreign sources do not contain dangerous amounts of asbestos. They've tried to make that point several times over the past 10 or 15 years.
--
Ed Huntress


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On Thu, 14 Apr 2011 02:24:28 -0400, "Ed Huntress"

A technique I have discovered that works VERY well is to preheat to a dull cherry red and then TIG with stainless steel wire. If the part is CLEAN when you start, and you properly "V" out the joint, I have not had a single repair fail.
I've done (or had done) exhaust manifolds, lift quadrant and other John Deere tractor parts, decorative cast, and all kinds of machine parts this way - and it WORKS.
The stainless alloys with the cast making the metal around the joint stronger and less brittle than the original metal, and more ductile - so it doesn't crack as it cools. (don'r quench or quick-cool, obviously)
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On Wed, 13 Apr 2011 22:15:14 -0700, "Steve B"

I'd use oxy-acetylene, railroad rod and Ferro-flux. I don't know where you'd find either railroad rod or ferro-flux these days, but I've mended many broken cast iron pieces with gas, railroad rod and ferroflux.
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On Wed, 13 Apr 2011 22:15:14 -0700, "Steve B"

==================Have you considered brazing or silver soldering? Any reason that it must be welded?
-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).
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wrote:

What he SHOULD be considering, is consulting with an attorney.
--



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On Thu, 14 Apr 2011 03:26:48 -0500, F. George McDuffee wrote:

Brazing can work very well on some cast iron parts if you can build up a heavy collar of brass all around the fracture. I repaired a broken lathe control lever, about 3/4" diameter round bar where it fractured, and one of the lathe legs, about a 3" x 3" angle x 1/2" thick at the fracture. Both collars were about an inch long and 3/16 to 1/4 thick. Requires a lot of brazing rod (cheap), room for a collar of extra material with more cross sectional area than the fracture, and the ability to deposit a thick layer of braze, which as I recall took a bit of practice.
Whatever method, preheat must be enough to burn out the oil that cast iron machine parts inevitably absorb. Grind clean then heat to blue works.
OA welding with matching cast iron rod can deliver good results too. I recall someone making a 6 cylinder head with big valves and ports by gas welding 2 sawed off pieces of V8 heads together using rod made by melting and pouring bits of the sawed off head ends into the groove of angle iron. He cleaned up in his drag racing class with it. Hot preheat and really good distortion control technique required.
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SNIP
Unless it's a real oddball these folks probably will have a used or new part, for a good price. http://www.valu-bilt.com / Steering parts are usually under a LOT of stress. Unless it's a museum machine or something where only 5 were ever built I would replace the part.
If you are going to repair it I suggest, CLEAN the part well. If it has held oil use an oven to bake the part and drive the oil out of the casting. Then clean it. Then grind a good bevel on both areas of the break. Preheat the part (I use a modified BBQ grill for small parts) You want it at least 500 or so (hotter is better to a point) Now weld it. You can use a stick with nickel rod or if you have TIG use it with nickel filler. Preheat, weld a small section, hammer it some to relieve stress and toss it back on the heat. Continue until the weld is finished. Now let the part cool SLOW, The ideal way would be in a temp controlled oven where you can ramp the temps down slowly. (I have an ancient electric oven I use for this (also gets used for powder coating and plastic forming, as well as the occasional snack...) You could also put a layer of lime or vermiculite or even sand in a metal pot/box/whatever, lay the hot pat in there and cover it over. Then let it cools down.
--
Steve W.

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wrote:

It is the part that goes from the tie rod to the front wheel. The piece that pulls and pushes the wheel, and it has a LOT of force put on it.
Steve
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"Steve B"

Then it definately is _not_ cast iron! And brazing this will not hold. You must weld it, I'll bet it is high strength cast steel. phil k.
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What Phil said: NOT cast iron, no brazing, weld only, use a high strength alloy rod/filler.
On 4/15/2011 8:29 AM, Phil Kangas wrote:

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On Thu, 14 Apr 2011 22:39:20 -0700, "Steve B"

be correct when he wrote On Thu, 14 Apr 2011 08:58:34 -0700 <snip>

<snip>
Given the potential for product liability if this breaks, the smart thing appears to replace the part rather than attempting a repair, particularly as it has failed once, and ==>the part should be stronger than new for a good repair.<== Even if you get a "hold harmless" agrement, if a third party is injured or killed you may still be "on the hook." If commercial shops have refused to repair the part this should be a red flag.
The old axiom "just because a thing can be done, is no justification for doing it" appears to apply here.
-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).
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appears to

That was my first thought. After a couple of days of analysis, my neighbor has decided to take it to the shop and have a new one put on it, as well as some other work needed that he was "going to have done one of these days."
I told him that I could not guarantee the work, and it could last 20 seconds or 20 years. There's quite a bit of disassembly required to just get the part where one could weld it, and if it's all apart that much, it would be easier to just slap another in there. If it failed, it would be back to square one, and all the disassembly again. So, the problem has resolved itself.
I know in other lives, people fixed anything on the farm themselves, shops and money being in short supply.
Thanks for the info, everyone.
Steve
Heart surgery pending? www.cabgbypasssurgery.com Heart Surgery Survival Guide
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Steve B wrote:

If it is the drag link itself it is a forged steel part. If it is the sector link (part that attaches to the steering box and moves like a lever) Then it is cast steel. About the only cast iron in the steering would be the steering box, the front axle and hubs and the bolster.
Being this is the drag link then I would suggest welding it, BUT first find a section of steel tubing that will fit over it. Then weld it up good and grind it so the steel tube can slide over the repair. Then weld the tube in place on both ends.
--
Steve W.

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On Fri, 15 Apr 2011 14:45:06 -0400, Steve W. wrote:

Before welding a fractured part it is always a good idea to find out why it failed. If the part is well within its normal service life expectancy and failed due to a one-time severe overload from something like driving into a tree, then it might be worth welding, especially if the replacement is expensive or hard to get. On the other hand if the part was well into its normal service life and failed in normal service then it has likely suffered metal fatigue damage in all stressed areas, which welding cannot fix, and the welded part will most likely soon fail somewhere else. In this case a weld repair should be considered a temporary emergency fix while waiting on a replacement.
Glen
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My thought was to sleeve it, or weld bracing on it. Trouble is, it's about 1/2" from a bolt, and can't get a lot of weld on that short of an area.
But he has decided to take it to the shop anyway and have it replaced.
Steve
Heart surgery pending? www.cabgbypasssurgery.com Heart Surgery Survival Guide
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wrote:

Did he describe the drag link or the steering arm?? I envision the steering arm, which bolts to the steering knuckle or the king-pin, depending on the tractor design. What make and model is this tractor anyway ? Might make a BIG difference on whether to repair, replace with used part, or fabricate a new one.
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It's a Massey 1246, and it is the piece that goes from the tie rod to the front axle, and it turns the wheel. HTH.
Steve
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You probably mean the steering arm that connects the tie rod to the spindle.
http://shop.ebay.com/i.html?_nkw=massey+steering+arm
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