Dick, Since 1955, I have saved a lot of cracked and broken cast iron
things,
from stove grates to various brackets and housings, and even fixed a sausage
stuffing machine for a relative one time ........ and have altered a whole
bunch of
exhaust manifolds for swaps, etc. I always used my torch and brass rod and
my
trusty old Brazo brazing flux and had excellent results, but one of my old
dragging buddies from the 60s brought me his 440 Mopar block from one of his
street machines, with a crack about 15 inches long on each side of the block,
just above the pan rail ........ typical result from lack of antifreeze in a
car sitting
outside in our northeast winters . I told him to get another block, but he
gave me
a sob story about it being recently bored and the new pistons and all, so he
talked me into taking a shot at it, and we decided to try a method I had not
done
before . It was on a really cold winter day, so I had him keep the wood
stove
really stoked up, and got it about 90 F. in there and let the block soak up
the
warmth, and then I preheated each crack area with the torch, and then stick
welded it with an ac welder and welding rod known as Ni rod . I did short
tacks
about 1 1/4" apart , and then tacked between the tacks, jumping from one end
to
the other to spread the heat out, until the tacks were about 1/4 " apart .
I did not try to weld these cracks to be leak proof ....... just to hold
everything together .
After a long cooling off period, my friend applied two separate layers of
fibreglass
strips and epoxy resin, cured with a heat lamp , and it seems to have worked
very well, as he still has the car more than 20 years and many fast miles
later , and I
asked him a year ago if he ever had a problem with it . He said no, but
the
engine needed another rebuild ....... which is the business he is in .
I do not like to weld or braze on cast iron ....... when you grind it,
the dust is
really nasty ...... and hope I never have to play with any more of it .
By comparison, STEEL has endless possibilities and is GREAT to work with
!!!
I have never attempted any welding on cast iron with MIG, but Jack
788
Low Low Liner says it' s worked for him, and that just goes to show there are
often many solutions to a single problem . Dick, check with your local
welding
supply house and see what they recommend ........ there are many new products
and techniques around since we sweated in that hot garage to save that
Mighty Mopar. Old techniques + modern techniques / goodies = better rodding !
Good Luck with your project !
Bruce
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