Dave Tesch writes:
> monkeylad@mac.com writes:
>
> >If you've seen lots of crashed and/or fatigue-cracked
> >frames, [snipped]
>
> Sounds like someone is desperate to validate silver brazing,
Sounds like someone isn't paying attention. The Monkeydude didn't write the above quote, I did. And the whole gist of my long-winded spiel was that silver *isn't* necessarily better just because it's lower temperature. I was pointing out it's not that simple, and came right out and said a good brass joint is better than a bad silver joint.
The fact that steel frames more often fail a little ways away from the lug
edge instead of right at the lug edge is an advantage, a bonus - not a slam
at your chosen lifestyle.
> [...] it is totally entertaining to read this nonsense.
Admit it, you didn't really read it, right? Just sorta skimmed it? Cuz it wasn't that entertaining. It's ok to sleep in class if the lecture is too boring (and you took this class already, long ago...), but don't wake up mad about something you dreamt and take it out on me.
I brazed thousands of lugs with brass and they didn't break. I like brass. I just like silver a little more. There's sure nothing wrong with brass though and I never said there was. Quite the contrary. When I came back to brazing lugs with brass for a living after three years of making mostly Ti, it was really fun and easy, I was pleased to see I hadn't forgotten how!
At one shop I worked in we did calibrated crush testing of sample lug joints. This was in '85 I think, thus almost on-topic for this group ;) We borrowed Charlie Cunningham's frame crusher, which simulates a front-end collision, and brazed a couple dozen headtube-downtube joints with different tubing, and silver and brass. We had multiple samples of each combination, Reynolds/silver, Reynolds/brass, Columbus/silver, etc. The brazing was timed so all samples got a similar heat cycle. All samples were brazed by the same guy (me). I had 7 years pretty much full-time brass brazing experience at that point; a good bit less silver lug brazing experience. All the samples were very well brazed though, with short heat cycle (about 2 minutes) and low temps.
It wasn't exactly double-blind, but I was only interested in finding out, not in skewing the results any particular way. In fact we changed our way of building because the results surprised us a little.
Prior to the test we had started making frames out of Prestige, silver brazed. We thought Prestige had to be silver brazed because it was heat-treated. Though the silvered crush victims consistently came out a little stronger than the brassed ones, it was little enough that largely as a result of those tests, we switched to brass brazing - which conventional wisdom said you weren't supposed to do with heat-treated tubing. But we liked the mellower way the steel frames crumpled, not right at the lug edge like with silver; and it seemed like the steel joints, though a tad weaker, were absorbing more energy as they bent than the silver ones did - a property known as toughness by the materials science people, very good to have in a bike frame.
My reasons for preferring silver (slightly) are mostly personal, you might say de gustibus. It's not because brass sucks. I don't need to "validate" silver or brass because both were perfectly valid long before I came along. It seems to me that the people I've run into who think one is *way* better, usually don't have enough experience with the other to base their judgment on.
Well there I go rambling again and Dave's probably nodded off again and rightly so, it's time for me to do the same.
Mark Bulgier
Seattle, Wa
USA