if the pipe is painted though you would need to get rid of that. Most cast
iron is not that smooth, so you would need some kind of non shrinking filler
as mentioned.

A word of warning though. Are you absolutely sure there are no other cracks
in the pipe? It tends to happen to cast iron if under any stress for a long
time that cracks grow and propagate, depending on where the minute flaws
are. It might be that in the end a new plastic pipe is less of a hassle.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Ian Jackson" wrote in message
...
In message , Lobster
writes
Investigating the cause of a damp patch on an internal wall, I discovered
a
crack in a cast-iron downpipe; looking at it more closely I found that the
crack actually runs the entire circumference of the pipe, and it's
possible
to raise the upper section and see daylight between it andthe lower
section.

********.

I know it would be a relatively trivial matter to replace the downpipe
with
a 'nice new' plastic item; however, I'm rather attached to my original
100-
year-old cast-iron rainwater goods, and I'd really prefer to hang on to it
and repair it instead.

What would be the panel's reccommended method?

Thanks

I'd be tempted to fashion a sleeve - possibly from a bit of plastic pipe
of similar diameter or slightly larger diameter. Cut the plastic pipe in
half - into two 'shells' - that can be offered up to each side of the cast
iron pipe. To get a good fit, a hot air gun can be used to soften and
slightly re-shape the plastic pipe.

The actual gap in between the two halves of the pipe could be bridged by
self-amalgamating tape (although this might not be necessary)

Butter-up the inner sides of the two halves of the shells with car body
filler (preferably the plastic type of Plastic Padding), and place on each
side of the cast iron pipe to form the sleeve. Hold in place with wire or
very large cable ties - or something much more businesslike - like say
several large Jubilee clips ('in series', as required).
--
Ian