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Radial arm saw welding repair cast iron any advice apreciated ?

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Forum topic by SCOTSMAN posted 07-05-2013 07:02 PM 1033 views 0 times favorited 16 replies Add to Favorites Watch
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SCOTSMAN

5426 posts in 2273 days


07-05-2013 07:02 PM

I have a foot off my radial arm saw broken with a large piece remaining and two smaller pieces broken.I spoke to my old college lecturer and he says castweld has ( He thinks ) been superceded by anew ways of welding and is trying to put me in touch with his pal who is a great nwelder .Anyway what is the latest on welding cast iron.I wouldn’t rely on brazing and cast welding is old hat( I think ) please help me with advice.Buying a new piece is not on really as they cost four or five times the worth of what I paid for the machine ,If you copuld get one the machine is vintage 1964 back when I was 12 years old can you help with polite suggestions. LOL Alistair

-- excuse my typing as I have a form of parkinsons disease


16 replies so far

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JoeinGa

3335 posts in 695 days


#1 posted 07-05-2013 07:36 PM

Might be able to fix it with JB Weld. Pretty amazing stuff. I’ve fixed engine blocks with it before. Just build up enough JB Weld and grind it back into shape

-- Perform A Random Act Of Kindness Today ... Pay It Forward

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SCOTSMAN

5426 posts in 2273 days


#2 posted 07-05-2013 07:39 PM

what is jb weld I figure honestly this would hold just using the rear piece as it’s still abig chunk with two large bolts so if JB weld is a kind of glue it may work please explain what this is Alistair

-- excuse my typing as I have a form of parkinsons disease

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Porchfish

576 posts in 1221 days


#3 posted 07-05-2013 07:44 PM

I concur with Joe in Tennessee . After talking to my neighbor who is a master TIG welder and has welded just about everything, he cautions against trying to work with cast iron, because as he puts it, there are so many variations in iron used for casting that he doesn’t suggest fooling with it and concurs that for the repair you are considering a product like JB weld and a good grinder may well be your best alternative.

-- If it smells good, eat it ! The pig caught under the fence is the one doing all thesquealing

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JoeinGa

3335 posts in 695 days


#4 posted 07-05-2013 07:46 PM

JB Weld is like a glue, but it’s some kind of polymer(?)
You can fill holes in engine blocks to seal them.
You can use it like a glue on pretty much anything metal, it’ll adhere to most any type you put it on.
You can grind it, drill it, and you can also build up enough to actually tap threads in it.

It’s 2-part stuff that you squeeze equal amounts from both tubes and mix thoroughly (like epoxy). But play with it a bit first on a practice piece, because if you wait too long it’ll set up on you while you’re trying to work it. It’s sets up pretty quickly.

-- Perform A Random Act Of Kindness Today ... Pay It Forward

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Porchfish

576 posts in 1221 days


#5 posted 07-05-2013 07:52 PM

OK lumberjocks edit button is screwy and wouldn’t let me finish my post. I had to break to warm up my coffee, anyhow, JB Weld is a steel reinforced epoxy that is easy to use. It comes in many forms now from the original epoxy, to a steel reinforced donut stick type product…available in most home improvement stores. If you look it up on the net you will see what varieties are available and which will work best for this instance. Alistair, this should provide a quick affordable fix. Good luck mate and let us know how it works for you. don s.

-- If it smells good, eat it ! The pig caught under the fence is the one doing all thesquealing

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REO

628 posts in 762 days


#6 posted 07-05-2013 07:58 PM

I have had no trouble welding or brazing cast. I have done my fair share. I wold trust brazing over JB weld anytime. obtaining a consistant bond area temp and maintaining for a SLOW cool is the main factor.

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Planeman40

485 posts in 1449 days


#7 posted 07-06-2013 02:47 AM

I agree with Reo.

I have been gas welding for a half a century now and I can’t see why brazing (with brass) concerns you. Its only a foot of a machine and brazing, if done properly (like anything else), should be plenty strong. And as the heat required doesn’t reach the melting point of cast iron, the repair won’t be as touchy as welding cast iron. If it were me, that’s what I would do.

Planeman

-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

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crank49

3458 posts in 1659 days


#8 posted 07-06-2013 06:30 PM

JB Weld is glue.
Good glue, but still glue.
This glue might develop a couple thousand PSI tensile strength.

A brazed joint can develop 60,000 PSI tensile strength. 30 times stronger.
The original cast iron might have had a tensile from 30,000 to 60,000 PSI, so the brazing is as strong as the base metal. The glue is not any where near that.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View Joe Lyddon's profile

Joe Lyddon

7799 posts in 2740 days


#9 posted 07-07-2013 12:34 AM

JB WELD is SUPER SUPER SUPER Glue…

Great stuff… I’d sure try it!

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: http://www.WoodworkStuff.net ... My Small Gallery: http://www.ncwoodworker.net/pp/showgallery.php?ppuser=1389&cat=500"

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SCOTSMAN

5426 posts in 2273 days


#10 posted 07-08-2013 06:58 PM

I am going to use jb weld and have ordered some, and if this is not enough I will bolt some strapping flat bar from below and use countersunk headed bolts which I can fill with car body filler and make good from above .I honestly believe though the jb weld will be enough.Thanks to everyone for advice and will keep you posted Kindest regards Alistair

-- excuse my typing as I have a form of parkinsons disease

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SCOTSMAN

5426 posts in 2273 days


#11 posted 07-08-2013 08:45 PM

I should also point out a small (perhaps) error in my original posting.I don’t mean the foot of the table as in four feet bench I mean the part which is technically called the foot but is the main support for holding the upright support of the radial arm,head and all.But as said there is actually I believe enough metal (meat) to have it stand alone as is with the two boplts that currently hold it as it is designed for four bolts altogether and anything I do will only add strength to the foot support.I thank you guys so far. Alistair

-- excuse my typing as I have a form of parkinsons disease

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Charlie

1048 posts in 974 days


#12 posted 07-08-2013 09:41 PM

I used to have to weld cast iron flywheels. The machine operators…. I have no idea what they were doing, but they used to crack the flywheels right at the hub where they got bolted to a flange on the main shaft.

Anyways… getting a new flywheel meant waiting for one to be shipped from Germany. One guy tried to weld one and you could watch the weld cracking just a couple inches behind where he was still welding. My dad was a welder for many, many years. For this cast iron we had to stick the flywheel in an anealing oven (we had some you could drive forklifts into) and heat the whole piece. We had to get them really hot…. well over 1000 degrees and then weld them. I think the melt point in this particular cast iron was 2150 to 2350 or there abouts, but you had to heat them so they glowed before you welded them.

Not sure if that’s the way a master welder would do it. It’s just something my dad showed me when I was young and in this case it apparently worked. :)

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Grandpa

3182 posts in 1364 days


#13 posted 07-08-2013 09:49 PM

When I was a kid we owned a “C” Farmall tractor. This tractor has a tricycle front end. The shaft that holds the front wheels goes into a cast iron casting on the front of the engine. This bolts to the engine, a worm gear for the steering run though this part and some spur gears fit in from the bottom. The sides of this part holds the row crop cultivator on the tractor. The coolant for the engines goes through this part also as I recall. Anyway we broke this casting from on side to the other. The part was $100 back when my Dad was making $1.50 an hour. We just had enough to get by on without laying out $100. WE took it off and took it to a blacksmith shop. The man there brazed this back together and said he would guarantee it to never break in this place again because it would be stronger than the original part. Well, it later broke again but he was in the clear because it broke in a different place. totally different angle. I am sold on brazing. Now all you need is a good man on the torch. JB weld is good but brazing is great.

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REO

628 posts in 762 days


#14 posted 07-09-2013 03:02 AM

900 to 1100 is usualy the sweet spot for welding cast hotter and it affects the crystaline structure of the material in the HAZ. but the temp has to be maintained consistently and the cool down is critical. I did some punch press fly wheels and some large gearbox castings (over 500 pounds) I dug a hole in the back yard and filled it with charcoal ran a pipe with holes drilled in it from the exhaust of a vacuum cleaner to make a pit forge. To weld I laid on the ground next to the pit and stuck a rod to the end of a four foot long holder. constantly checked the temp with temp sticks and spent the better part of a day heating and welding each piece. when the welding was done I covered the bed with high temp ceramic tarps and 2 feet of fiber glass insulation on top of that. on the morning of the second day it was just getting to the point of being able to keep your hand on it. pulled it out on the third day and put it back to work. I didn’t have the capital for a furnace. chuckle. I was told how to do it by a fellow who welded diesel engine heads while he was in the service using a 55 gallon drum for a furnace. I just followed his directions.

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SCOTSMAN

5426 posts in 2273 days


#15 posted 07-20-2013 07:24 PM

Well thanks for your great input guys. I already repaired it with JB weld and it’s looking a performing as good as new .Wow that JB weld is some peiece of kit, everyone should have some in their toolshop. If it hadn’t been for you guys I would never have known about jb weld and now have four packets of it in my office for future useage I thank you all profusely. Kindest regards Alistair

-- excuse my typing as I have a form of parkinsons disease

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