Re: cast iron block

["Graydon D. Stuckey" <graydon@apollo.kettering.edu>]

On Tue, 17 Aug 1999, Mike Mulholland wrote:

> re welding cast iron...
>         cast iron is a very poor medium to weld. if its a fine grain
> investment casting it's ok but, an engine block is a big dirty casting. what
> works best imho (btdt)  is bronze brazing. i have tried oxy/acetylene, arc,
> and tig. use low temp, low fuming bronze and apply a liberal coat of paste
> flux (or powdered flux added to water) because you're heating a huge
> heatsink be patient and heat slowly and carefully to avoid hot spots which
> could burn the flux and ruin the job.

Sounds like good advice.

I welded my 5KCSTQ exhaust manifold a while back.  I used stick welding
rod for cast iron, but I chipped the flux off of it, and used it as filler
rod for my TIG welder (Lincoln Squarewave 175 - nice machine.) I heated
the manifold up a little first, and I drilled small holes at the ends of
the cracks to prepare it.  Then I also made a healthy groove along the
cracks so I had nice clean metal to weld.  It worked like a charm, and as
far as I know, is still holding together. 

When I was done, I sanded the mounting face on a 3' dia sanding disc to 
make it flat.

Later,
Graydon D. Stuckey
'91 V8 Quattro 5-speed		'86 Mazda RX7 TII+2
I have a new exhaust systems webpage - check it out at...
http://www.geocities.com/MotorCity/Factory/8023/index.html