[Farmall] OT check this out

[Matthew Gray]

http://talk.newagtalk.com/forums/thread-view.asp?tid=11971&mid=79011#M79011


----- Original Message ----- 
From: "John Hall" <jthall at worldnet.att.net>
To: "Farmall/IHC mailing list" <farmall at lists.antique-tractor.com>
Sent: Wednesday, December 27, 2006 3:43 PM
Subject: Re: [Farmall] O-12 chores


> I've seen two different guys weld cast with something besides nickel rod. 
> One welded dad's 10-20 manifold with a mig gun years ago. This was before 
> I ever started getting an education on cast. Anyway, it is still holding.
> I used to work with a guy who Tig welded heads for a machine shop and 
> guaranteed his work.
>
> Most guys do as you say by preheating the parts and then slowly cooling 
> them. One friend used tohave a cookstove in his shop for controlled 
> cooling and heating. When I welded up the fuel pump on my Titan I heated 
> it real hot and kept it that way. Careful you don't get too hot and get a 
> blow out when welding--especially if you hit an air pocket. When done I 
> buried it in a bucket of sand to provide slow cooling.
>
> Of course you need to start welding some non-critical parts first. Then 
> you get to experience first hand what happens when you missed drilling out 
> all of a crack---10 seconds with the rosebud and then.....well, lets just 
> say cast iron can take you to school, and might send you home crying.
>
> There have been some good threads on cast welding on either the AT or SEL 
> list---may have been on both. Some pretty knowledgable folks there.
>
> By the way, McMaster-Carr is a good place to get odd and end pieces of 
> matl. for machining.
>
> John
> ----- Original Message ----- 
> From: <olmstead at ridgenet.net>
> To: "Farmall/IHC mailing list" <farmall at lists.antique-tractor.com>
> Sent: Tuesday, December 26, 2006 2:45 PM
> Subject: Re: [Farmall] O-12 chores
>
>
>>I agree that I have little to lose, John.  And welding cast iron is
>> certainly a talent that I would like to have.
>>
>> What scares me is the guys who say "I've welded lots of cast iron, just
>> zapped it with the MIG, and it worked fine".  That goes against 
>> everything
>> I've ever read about what happens in the iron adjacent to the weld, which
>> gets very hot and then chilled by the base metal.  It winds up being very
>> brittle and under a lot of stress.  In order to do a lasting job on cast
>> iron, the whole part needs to be virtually red hot while you are welding,
>> and then cooled very slowly.
>>
>> Then there's the problem with porosity, contaminated metal, warpage,
>> cracking and so on.  Doing it right is not a simple matter.  I figured
>> that I might be able to learn to braze a lot quicker than to weld.
>>
>> Brazing and soldering are also magical techniques.  In order to do what
>> the experts do, you need to control the temperature of the pool so 
>> closely
>> that you can keep it in the 'mushy' stage, where it doesn't liquefy and
>> run right off the work.  I've never been good at that.
>>
>> Gotta obtain some 2" round stock before I can start making crank
>> supports....  none in my scrap pile.
>>
>> -Karl
>
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