In a message dated 7/1/02 3:06:47 PM Pacific Daylight Time, chuckschmidt@earthlink.net writes:
<< Never heard of a "soft" brazed joint on a steel bike... maybe an
incompetently brazed joint, but never a soft one.
>>
Comments are reserved for old school tubing. If you get it too hot, a lot of
the strength goes away. Columbus states in their catalogue that if you keep
it to silver brazing temperature, the tubing only loses 5% of its strength. I
had a brand new Eddy Merckx. I cannot begin to tell you how little effort it
took to move the frame a lot! It wasn't the tubing. A silver brazed frame
with the same tubes was a "mofo" to move. If you heat it enough, you ruin the
steel. We could get technical and say it's from improper i.e., too rapid,
cooling or any number of other things. My understanding is it isn't
necessarily heat (within limits) but, time-at-temperature, that counts.
That's why someone really good can build a strong frame using brass. It's
hard to get that good joint quickly using brass.
Stevan Thomas
Alameda, CA