cast rion repair - braze/weld diy?

[kenc]

I recently bought 1944 vintage pexto 52" shear. I never noticed a crack in one of the castings. Now I need to decide how to proceed. Of course, the smart thing would be to take it to someone experienced in cast iron repair, and maybe I still will, but I don't really want to spend a lot on the shear as it only cost me $400 to buy.

If I attempt this myself, I am thinking that brazing - or strictly braze-welding is probably the best way to go for me. I've read enough online about both gas or stick/Mig/Tig welding cast iron to realize that it's a pretty involved task to avoid post weld cracking.

The only brazing I've done in the past is simple t-fillet welds in welding class years ago - am I likely to be successful or is it foolish to try?

I would drill the end of the crack to stop the crack progressing, then Vee out the crack to 90deg, then have at it with the brass.

IS there a preferred rod, or flux that might make the job easier/better?

Any and all advice appreciated before I have at this beast!

The crack terminates up at the black pen marks in the pic below.

http://www.hobartwelders.com/weldtalk/attachment.php?attachmentid=30029&stc=1&d=1258251953

[vicegrip]

I'm afraid you have purchased a puppy that has issues.

Look to about 8:30 O'clock from the crack and see the other weld.
This poor thing has seen abuse or an accident.
Doesn't mean it's hopeless but $400 ..... yeiks.

Looks like a learner project if you can't return it.
That crack is there because of a bad closure.

VG

[Rocky D]

I don't see a problem stick welding with Certanium 889. The fact that you have another weld on there is evidence that it can be welded...I don't have much faith in brazing. The trick is to allow it to cool slowly, by covering the welded area with kitty litter, Kaowool (preferred) or fireblanket. Stop drill, and Vee out the crack, and if there's oil present, you will have to preheat to boil it out. Piece o' cake.

[DonG]

Wish I could post this using someone else's name so you won't think I'm a total putz.

I have an exhaust manifold from early 30's Dodge that had a couple of small cracks in it. Since I am taking a welding class (just for fun) I brought it into class. Instructor said It would be difficult if not impossible to weld considering it was a manifold and the age of it. He offered to do it for me. I said sure. He fired up the TIG with some special rod and things did not go well. Spattered, exploded and just wouldn't stick. Then he tried brazing with a couple of different rods. Same result.

Took it back home and decided to try it myself since I had nothing to lose. Had a few different brazing rods; plain no flux, flux coated and some rods I bought several years ago from (and here is where I want to hide my name) Menards. Made by American Forge with a red flux. Package claimed it could do anything. Well, IT WORKED GREAT! Heated up the manifold with my torch, brazed it and kept heating it with a MAPP gas torch periodically for about 90 min. Cracks gone, no spidering.

So I say, give it a try.

Don

[kenc]

Thanks Guys.

I must day the shear is a bit of a pig-in-a-poke. I was careful to ensure that it worked well (which it does) and that the blades weren't worn out since the cost of replacement blades can cost as much as the shear itself.

I stripped it down today and there are a lot of braze welds in the cast iron parts. Looks like it was dropped at some point - both leg castings are had been broken in half. Plus a few other repairs here and there.

Well, I suppose it is 65 years old. And stuff costs a lot here in the SF bay area - we don't get anything cheap.

I think given my experience level, I am going to braze it. Heck if brazing can successfully hold the **** leg casting together on a 1000lb machine then it must be plenty strong, no?

[Hotfoot]

Keep us posted...Success or failure. We learn in all instances!:)

[vicegrip]

Thanks Guys.

I must day the shear is a bit of a pig-in-a-poke. I was careful to ensure that it worked well (which it does) and that the blades weren't worn out since the cost of replacement blades can cost as much as the shear itself.............

.................Heck if brazing can successfully hold the **** leg casting together on a 1000lb machine then it must be plenty strong, no?

No; not actually, but a good nickel job should.
The reason I chimed in this thread is that.........
The split I see, is nearly allways from the same cause!
An imbasile, attempting to shear multiple sheets of thin stock.
The blanks fold and tip and spread the blades .... CRACK!
The painted weld I see looks like a good weld but is from attempting
to shear too thick of metal on one end of the shear.:eek:

Good cleaning some practice and correct preheat, and nickel
will do you proud. Find a like casting and give er'.

Cheers
VG

[Hotfoot]

Keep us posted...Success or failure. We learn in all instances!:)

[vicegrip]

He does live by Canyon lake after all.:D

vg

[chibornick]

I have welded exhaust manifolds and turbo snails by v-ing and tack welding for alignment, then full weld with 7018. After it is done toss it on the cement floor ,if it breaks you have a clean break to work with,if it doesn't your done.