"_" wrote in message
...
On Fri, 13 Mar 2009 20:49:11 +0900, K Ludger wrote:

"_" wrote in message
...
On Fri, 13 Mar 2009 00:56:44 GMT, _ wrote:

Won the battle to remove motorcycle header pipes from the "slip-on"
(yeah
right) 2-1 collector - multiple applications of penetrating oil,
electrolytic derusting, fitted wooden clamping blocks, finally used a
propane flame to get the outside pipe red hot and then they shifted.

Two of the header pipes have not-so-small dents in them. Right now
they
are outside, filled with water, and it's supposed to drop below -10
centigrade tonight.

I'll have a look in the morning and let you know what, if anything,
happened.

The dents are gone - fabulous.

One of the pipes has a crack in it now, on the outside bend of the 90
degree elbow. Perhaps next time it would be better to avoid so much
putting water in it - the dent wasn't in that part.

Oh well, after it melts the crack can be welded shut again - easier to
fix
than the dents would have been.


great - out of interest did you cap the ends in any way?

No - capping was something I read about, but people also said they had
done
this without, so as that was easier I tried it first. Apparently what
happens is the ends of the water tube freeze first, forming caps in situ.


That makes sense.


Brazing the crack might be a tidier fix - will the plater be able to put
chrome on a brazed joint?


I don't know, but brass is often plated - the gurus here will know.....

I imagine MIG/TIG and grindback & anneal may be better in terms of strength
& longevity.