On Mon, 30 Nov 2015 16:14:53 -0600, "Terry Coombs"
wrote:

Ed Huntress wrote:
On Mon, 30 Nov 2015 11:03:44 -0800 (PST), "
wrote:

On Monday, November 30, 2015 at 1:29:58 PM UTC-5, Ed Huntress wrote:

I think that welding cast iron has had enough written about it to
fill a book. But this is a subject on which I'd want to talk to an
expert, to fill in some of the questions that the books don't
answer.

--
Ed Huntress

I think one of the problems is that each welding job on cast iron
needs to be thought about and evaluated. In some cases the
contraction of the weld material will not cause a problem. And
example is when you are welding two pieces together. In other
cases the contraction will put stress on the cast iron. Like
welding a spoke that broke on a spoked gear.

Dan

I'm curious about whether there is a good non-destructive way to
measure the post-weld stress. I recall something about an exotic lab
technique, which I read about years ago, but maybe there is something
newer.

Anyway, I have to talk to the people at Lincoln pretty soon, so I'll
see if I can remember to ask about these things.

Geez , I never meant to cause all this stir ...

Hey, this is the kind of stir we're here for. d8-) Welding c.i. has
always been a really tough issue, and one that raises all kinds of
questions. I'm sure that many of us wish we knew more about it. Advice
tends to lead in all directions.

FWIW, years ago (1980s) I read about a c.i. welding job that would
make anyone sweat bullets. Harrah's automobile collection included one
of the few Bugatti Royales ever built -- there are only a few of them
in existence, and they are truly in the "priceless" category -- and it
had a cracked c.i. block. So they imported a guy from Italy who was
supposedly the best at crack repairs in classic car engines. Not only
did it have to be sound, but it had to be nearly invisible.

He used O/A (with lots of pre-heat, no doubt) and a cast iron rod.
After he welded it up, they put the engine together, started it, ran
it for a few seconds, and then shut it down, never to be run again.
Supposedly.

OK , today I did some
testing . My neighbor gave me a broken CI door from an old stove , so I cut
it up ... I cut some strips about 1/8 square and used some of that to run
some test beads on a piece of the door . I also ran some test beads on the
same piece with the NILO CF42 for comparison . Photos of the test piece will
be posted to photobucket when I get a few minutes to resize and select .
After trying both out on the scrap of CI I welded up the broken faucet
head , with mixed results . I decided to do it without preheat ... started
with the CI strips , ran into problems on the inside corner (those still
give me problems with TIG) and decided to finish with the NILO . I should
have preheated I think , there is what appears to be a hairline crack thru
part of the repair . Photos of that repair (before and after) will also be
posted when I get time to process them . The results of my tests are that if
I need to build up a CI edge or lip I'll use either one , but for crack
repair the NILO seems to give a better looking repair and is easier to use .
I will be using preheat and light peening as the welds cool when I repair
the stove grate . Decision of which filler will be made when I see the part
.