Best rod for cast iron

[Froneck]

I have a set-true type lathe chuck that the adjustment tabs are worn so that no adjustment can be made. Spot in the photo is about 5/16" wide and about 3/4" long. A tapered screw moves the tab to adjust the chuck. Screw simply pushes on the slot. I can braze it but don't want the heat! Material is Cast Iron. I do have a few different cast iron rods but they seem to bubble and leave pin holes. After welding I can turn the well tops flat in the late the chuck fits. I do have Eutetic cold spray torch, also hot spray but was thinking of putting the cold spray material in the hot spray torch. Simply put I want to fill the slot yet not get the plate very hot.

 

[guythatbrews]

I have a set-true type lathe chuck that the adjustment tabs are worn so that no adjustment can be made. Spot in the photo is about 5/16" wide and about 3/4" long. A tapered screw moves the tab to adjust the chuck. Screw simply pushes on the slot. I can braze it but don't want the heat! Material is Cast Iron. I do have a few different cast iron rods but they seem to bubble and leave pin holes. After welding I can turn the well tops flat in the late the chuck fits. I do have Eutetic cold spray torch, also hot spray but was thinking of putting the cold spray material in the hot spray torch. Simply put I want to fill the slot yet not get the plate very hot.View attachment 398319

That really doesn't look excessively worn.

 

[gbent]

From your picture I don't understand the problem, so I can't recommend a proper weld or braze filler. I have had good success using braze to pad the outside of cast iron parts to fill areas that have lost material. Arc welding can also be used, but tends to wash out sharp corners. As for pin holes, so what? Its not a pressure vessel, nor a structural weld.

 

[Freedommachine]

Tig brazing works quite well.

 

[magneticanomaly]

I am not aware of any metallic cast-iron joining or buildup process that does not involve, indeed require, substantial heating of the substrate. Heat is necessary to get a metallurgical bond, to prevent cracking due to differential expansion, and to force slow cooling to avoid hardening.

 

[Clive603]

Cast iron specific rods simply don't behave without proper preheating to an appropriate temperature, which can vary with rod compositions. Exactly what goes wrong, from blowholes to super hard surface that laughs at angle grinders, seems to be in the lap of the gods. But its never pretty.

However there is a field expedient technique using ordinary rods that works pretty well if done with care and appreciation for the limits of the joint.

Basic technique for joining broken parts is to generously Vee out the joint and build up thin layers of weld at minimum current to isolate the cast iron before final joining using no more than half the current and rod size that you'd normally use for that size material. During both phases of the job the weld should be peened with the chipping hammer immediately after completing each pass two stretch the weld layer and largely remove any cooldown stresses. Need to allow sufficient time between passes for everything to cool down properly so it doesn't get hot enough for dimensional changes leading to stresses at normal temperatures.

Obviously a slow old job. Given the choice use a versatile rod producing ductile joints. Cheap DIY types can be surprisingly good here. Had a white box of no-name, no specification number import rods that were very good at this and other envelope stretching jobs.

Last job I did was to stick some Victorian decorative cast ironwork back together. Horrible stuff with stupid amounts of free carbon left in the casting. Preheat that and it would probably have caught fire! Ended up looking like coal miner and scrapped the protective covering over the auto-dark shield. But teh customer was happy 'cos it worked.

Clive

 

[metalmagpie]

Unless a casting is quite small, the entire casting needs to be preheated to somewhere in the 800-1000F range before welding. After, it is very slowly cooled.

The best rod for cast iron is made of - cast iron. Nobody makes cast iron rod in this country any more. There is one company in Texas you can buy it from. It's good quality rod although it is made in India. I don't remember the name of that company but they repair valves.

metalmagpie

 

[Ries]

Least amount of heat is tig with a silicon bronze filler rod. If you need a stronger finished repair, nickel rod tig welding works without preheating the entire piece. Nickel rod is very expensive, though. Maybe fifty bucks a pound.

 

[magneticanomaly]

98% of the cast iron welding i do is with 55% nickel stick electrodes with 500 to 1000 deg Fpreheat, interpass, peen bead while hot, skip around, and slow cool.

Real cast iron rod, special cast-iron flux and oxyacetylene will work for some castings where SMAW will not, generally castings that have a lot of heat-history like old tractor manifolds or grate-bars.

I have also welded small simple iron castings with coat-hangers. It is finicky getting started because the cast iron's melting-point is much lower that the steel wire, b ut you get a gradient of lower and lower carbon,

 

[john.k]

I used to get busted Singer Sewing machine castings to repair where the boys had broken them.......best cast iron Ive ever seen.

 

[MrWhoopee]

I've had surprising success with 309L stainless TIG rod. YMMV

 

[Ultradog MN]

I have a CI project coming up.
Have to weld a crack in a drill press base that looks like it was dropped.
A friend of mine gave me this stuff to use.
I used some of this to weld the bell housing on a tractor a few years ago. It lays in a wobbly, lumpy looking bead but does a great job.
My old AC/DC buzzbox puked a diode on the DC side recently but I found a replacement for it.
I think? I used DC on that tractor but will be able to experiment with both sides to see which works better.
Am looking forward to it.

 

[john.k]

Stainless does weld cast iron.....the strength difference between the metals means very short beads are best ......long beads will deposit well ,but pull away on cooling........one of the better rods Ive used was phosphor bronze ......I dont know if such rods are made any more..........Ive used quite a bit of the various nickle rods ..........But ,always rods bought from clearing auctions ..........the shelf price of these rods is astronomical,and welding cast iron really uses them up in a hurry.

 

[CarbonArc]

Unless a casting is quite small, the entire casting needs to be preheated to somewhere in the 800-1000F range before welding. After, it is very slowly cooled.

The best rod for cast iron is made of - cast iron. Nobody makes cast iron rod in this country any more. There is one company in Texas you can buy it from. It's good quality rod although it is made in India. I don't remember the name of that company but they repair valves.

metalmagpie

Eutectic castolin also carries RCI-B (nodular iron) and weld fabulous carries RCI (grey iron) filler. I really like both of these fillers, easy to make sound welds with on good material.

 

[tylersteez]

As others have said, you will never get a nice cast iron weld without proper preheat. Once you get the piece at the right temperature, all of the wormhole issues go away completely and the weld pool behaves similar to a normal steel weld pool, but not fully. There's just really no other substitute aside from silicon bronze brazing

 

[john.k]

An amazing cast iron weld Ive seen was on the engine block of a flathead Continental .....the top machined head gasket face ..all the corroded area around the water spaces was replaced with a white filler .....I dont think it was pure nickle ,as there was no green colour......the deposit was an even 1/2" wide around each water hole in the casting

 

[CarbonArc]

An amazing cast iron weld Ive seen was on the engine block of a flathead Continental .....the top machined head gasket face ..all the corroded area around the water spaces was replaced with a white filler .....I dont think it was pure nickle ,as there was no green colour......the deposit was an even 1/2" wide around each water hole in the casting

More than likely it was cast iron filler. Big pieces like that are often furnace welded, I know because I do it.

 

[john.k]

It was white filler metal ,and not corroded by water.......I think maybe one of the spray metals.

 

[CarbonArc]

It was white filler metal ,and not corroded by water.......I think maybe one of the spray metals.

Spray on cast iron is usually nickel alloy as well (I do that too). When you say white, is it like a cream white??

The only other thing I can think of is nickel silver brazing rod, which would appear lighter than the cast iron I believe.

 

[john.k]

It was a motor in a forklift ,not something you expect to see in a low value environment.