[TheForge] welding cast iron

[theforge@mailman.qth.net]

Roger R Degner wrote:

>I have just gotten a very used/abused machine vise for a mill.
>The problem is there is the start of a crack in the casting in the part were
>the lead screw tightens.  Can this be ground out and then preheated and then
>TIG welded or is it just s heavy boat anchor
>Roger R Degner
>Franklin,Minn,USA
>
>  
>
I have welded these before, preheating the entire part to a red heat, 
welding it with nickel rod and then letting it cool slowly.   I let one 
part cool buried in ashes, and the other in an old gas stove.   Since I 
got my gas outfit, I tend to braze cast iron more often.       I have 
also successfully welded a crack in the water jacket of  an engine block 
in the vehicle.   This time, I laid the bead in, and as it cooled, hit 
it with a needle scaler.   No dreaded "tink", and seemed to be fine for 
the month or so I kept the car.    I was told the needle scaler trick by 
an old timer that did a lot of these repairs.   He would often weld up a 
cast iron part, then whale on it with a ball pein hammer.  This seemes 
to stress relieve it as well.   I prefered the needle scaler, since I 
had one, it was easier in the engine bay with limited room, and I felt I 
was less lekely to create a new crack by being over zealous.    There is 
a video of cast iron welding techniques available at:
http://www.tinmantech.com/html/cast_iron_welding_with_torch_a.html

The main URL is of course: http://www.tinmantech.com