Thu Jan 15, 2009 1:49 pm
Has anyone tried this stuff to repair cast iron? I've seen the "Alumaloy" TV commercials before but not this stuff.
It seems to be a type of solder or brazing alloy for cast iron.http://www.castaloy.com
Thu Jan 15, 2009 2:36 pm
Never used that material, so all my comments are just speculation. I suspect that it is a mostly-zinc alloy. The propane melting temperature is one tip-off. Probably not great for exhaust manifolds. And "stronger"? Might be referring to tensile strength of the zinc compared to cast iron. Knowing so little about the cast iron and the filler, my reference shows about the same tensile strength for certain grades of each material. The tensile strength/bond of the weld interface might well be lower. Nothing makes me want to rush to buy some. But it might be great stuff.
Last edited by Bus Driver on Thu Jan 15, 2009 6:05 pm, edited 1 time in total.
Thu Jan 15, 2009 3:14 pm
I'm with you Bus Driver.
All this hype and little substance.
When it sounds too good to be true, it is--stay clear.
Thu Jan 15, 2009 4:11 pm
Maybe I should give it a try. I have a BUNCH of old, good fer NOTHING parts laying around my garage. One of them is an old goobered up head. I wonder if using this castalloy on the head would seal up the crack well enough to use it? Would it hold water at low-to-no pressure? I am thinking of all the old discarded cracked lower bolsters (water cracks) that don't get any work stress and are not structural, but now leak like a sieve. Would patching with this kind of compound give them a new lease on life? I remember folks on this forum talking about fixing a lower bolster with JB Weld at one time and it holding like new... If this would seal in that same crack and be more similar to the cast iron and be "hidable" with paint, you could be in like Flynn....
I might have to pick me up some of this and experiment when the weather gets warmer...
Mike in La Crosse, WI
Thu Jan 15, 2009 6:08 pm
If this material has a practical application, sealing low-pressure, non-stressed, water leaks would be one of the ideal uses.
Thu Jan 15, 2009 6:30 pm
Is the crack where it can be "pinned?" I've pinned cracked castings with good results and its surprisingly easy. I would do that before using any sort of epoxy.
Thu Jan 15, 2009 6:39 pm
i saw something very similar at a rallye in lake george.the guy was repairing aluminum in the same manner. i wanted to try it but was feeling just a little to cheap.
Thu Jan 15, 2009 7:35 pm
I bought and used a similar material on aluminum with some success. Briggs 5 hp with broken place in the crankcase from broken connecting rod. Heated with oxy acetylene and hammered the crack flat, then sealed it from the inside with the similar rods. Worked well. Propane not enough heat for that larger piece.
Thu Jan 15, 2009 9:47 pm
how many propane torches would be needed to get a bottom radiator casting to 500 degrees for the Cast - a alloy to stick?
Thu Jan 15, 2009 10:01 pm
John *.?-!.* cub owner wrote:how many propane torches would be needed to get a bottom radiator casting to 500 degrees for the Cast - a alloy to stick?
Just send your wife shopping for the day and make sure the first pie out of the oven afterward goes to a bake sale in the next County
Fri Jan 16, 2009 7:53 am
This stuff looks like it's basically solder. It would have to be a pretty small part to heat to 500 deg. with a propane torch. There's no way the repair can be stronger than the original parent metal.
Fri Jan 16, 2009 8:35 am
It sounds like low tempature brazing right? Whats the tensile strength? If your just repairing a leak it maybe ok but i'm sure they have an epoxy or JB weld that can do that. Normal brazing rod is 20,000lbs tensile strength.
Nothing beats using the certanium castiron arc rod lets face it. Its very expensive but it does an excellent job. I have successfully welded dissimilair metals with this certanium castiron rod too. I welded steel gussets to a castiron motor housing once to save time in casting one to see how it acted under a stress test. It worked out well and my example/test also went into production too.
In welding anything its all about how you prep it, fixture it if it needs to be, preheat it and how you cool it that matters. Most castiron cracks can be repaired if its done right. I think the crack preperation is the biggest key to success.
2.Inspect the area to be welded
3.Prep the area to be welded. Drill two holes at the end of the crack so the crack can't continue after its welded. Its like putting up a stop sign for the crack.
4.Now carefully grind out the crack end to end to get more depth of weld into the metal. Depending on the situation i sometimes grind a 1/16" gap at the bottom of the crack so i get 100% weld into it. I actually "VEE" the crack to the surface of it.
5. Now preheat it with a torch. This will really clean it too of all oils/grease that maybe in the pores of the metal too. Once its heated weld it. Now chip it and reweld it until the desired amount of bead is on the material.
5. For cooling you need a box of sand to put the part in or if its too big you need to cover it so it cools slowly. I save my old leathers and welding gloves for this too. I cover the new weld up as much as i can so it cools slowly to room temperature. You can also draw it down with a torch slowly too if there is no other way to cool it slowly.
Arc welding castiron isn't that hard you need to follow the process closely for success.
Certanium also makes a superior 125,000lbs. tensile strenght rod too its there 707sp. You can weld it in a tee joint from one side(test). And try to break it. With regular welding rod the bead will fracture and break, but with the 707sp it work hardens to 250,000lbs. I personally tested this rod on my plow frame on my jeep tractor. I hit something while plowing that put the whole jeep in the air on the plow frame that i welded with the certanium 707sp. Nothing broke and i continued plowing. Even there mild steel rod is good for 90,000lbs tensile strength too. And yes i know most will say that normal steel A36 is 36,000lbs. tensile strength and the olde 6013 will do the job but in high stress areas i like having a big advantage in a safety factor. Working for an engineering group and some had off the wall ideas,i still slept good at night knowing my welds would hold up to any testing.
Fri Jan 16, 2009 8:56 am
sgtbull wrote:Is the crack where it can be "pinned?" I've pinned cracked castings with good results and its surprisingly easy. I would do that before using any sort of epoxy.
I've seen a method of what they call "stitching" cracks in castiron too. I seen this done in casting flaws and seams that looked like cracks. They have a drilling fixture that has 4 holes in it and they drill four holes inline across the crack. Then they use an air chisel to connect the holes with a slot. They they have a steel part that is the design of the four holes with the slot that fits tight into the holes/slot that they made. They epoxy it and bang the part in. Then they epoxy over it. Again they did drill two holes at both ends of the crack. This stitch goes across the crack to hold it closed and so it can't open up anymore. I've only seen this done on the large machine castiron castings.
I've had many jobs in machine building at different companies. I've seen one company that would scrap this part with the crack/flaw in the casting while another company would repair it.
Fri Jan 16, 2009 9:25 am
Old timers in this area used to weld cast by using cast rods, and running about 1/4 to 3/8 inch long bead, letting it cool, then again, etc. kind of slow, but I used it on a broken bearing block for a Brinley disk (tried to move it while frozen to the ground). It was still holding 4 years later when I sold the lawn tractor and equipment.
Fri Jan 16, 2009 1:52 pm
I took a freeze cracked calender to the welder and he used nickel rod. The weld did not hold and he said the cast iron just was not good enough to weld. I still need the cylinder fixed and am wondering if this stuff would be worth a try.
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