oliver casting repair

[48willys]

I'm helping my dad fix his Oliver standard 80.It had froze before he got it so the base of the radiator has a crack in it.Since parts are rare on the east coast our best option is to fix it.On to the metal working,I'v never done much brazing so I though I would get some ideas.Just a run down of my plan,drill holes at the end of each crack,preheat on the forge and braze with ox-ac torch,and bury in wood stove ashes over night to cool it slowly.
Any suggestions for what brazing rod to use,flux,plain,ect?Also,how hot should I preheat?Picture below of what I'm working with

[fciron]

Sounds about right, you can bring the whole thing up to a dull red for your preheat. Makes the torch work easier. I'd be paranoid and try to heat the whole thing evenly, in my experience these big, thin forms can be fussy.

[arftist]

You will need to vee the cracks. If you want invisible repairs you will need to vee them very deeply so you can clean off the top and leave sufficient strength. There are three ways to vee cast iron for welding, with a grinder, with a cold chisel or with a die grinder with solid carbide tooling. Of the three, the hard wheel grinder is least preferable though likely most common. Using a hard wheel causes the free carbon in the cast iron to smear all over the cleaned surface, reducing the chances of a good bond. A sharp cold chisel and time and care is the best, a die grinder with carbide bur is a good compromise. Of course I have used a hard wheel many times myself, but if you want to leave nothing to chance, don't do it.

Next, you will want to prepare a surface to work on which will not steal your heat. Fire bricks are fine, a bed of dry sand will work well too. When you are finnished brazing, gently play your torch on the surrounding areas to equalize the temp of the casting before burying in the wood ash. Bury it deep, at least 5-6 " of ash. Slow cooling is extremely important.

Don't forget to butter your joints, then fill.

[Still Learnin']

If you are going to weld, arftist has done a thorough job of explaining the process. I'd like to add one thing though. In my experience with cast iron I've found that peening the weld lightly after welding and prior to post-heat is extremely important. It lets the molecules reach a state of rest, or so I've been told. My dad has welding countless castings and he would always peen the weld, as well as pre and post heat. If you don't have any nickel rod, you can use stainless rods. If however, as you stated before, are going to braze... I would do the steps you already indicated and just use good old common 1/8" flux coated brazing rod. Drill before throwing the heat to it though because those cracks DO tend to propogate !!! Maybe migrate is a better word. Besides, after you weld cast iron, you couldn't drill it for the world. I don't know the explanation but it makes it like tool steel. I wish you the best in this endeavor.

Joe

[48willys]

1. I thought I would post a update on how this came out. I almost messed it up big time when I got the area of the crack to hot, and after all that I still had a pin hole. But the wood stove ashes did the job because it stayed together. So we fixed the pin hole with a little epoxy and put everything together, and so far its holding good after running it alittle but its hard to tell what it will do after some time.
   

[BIGGUNDOCTOR]

A friend back in CA had a dozen old Olivers at one time. Not sure what model they were though. You may want to check with the old tractor groups in Northern CA.

[Frank Turley]

John Neary aka Cracked Anvil, has said that cast iron is an amalgam of sawdust, molasses, and baby caca.

[Ten Hammers]

Frank, don't forget some Beech Nut tobacco juice and perhaps a piece or 2 of quid.....

I might add that I bury stuff (deep) in a metal barrel full of oil dry and come back tomorrow. Good suggestions on the process here fellas, thanks.

Local guy has an Oliver garden tractor with an RX-7 motor ( pulling tractor ).