In a message dated 3/12/2003 6:45:48 PM Eastern Standard Time, email@example.com writes:
<< Somewhere I read that the older Columbus tubes were limited in brazing temperatures to about 1300F (sorry if this isn't accurate; going by memory here, always dangerous); obviously, they had to be silver brazed, and there was quite a narrow range between melting the brazing alloy and overheating the joint. (I don't know if this is true of modern tubes.) Perhaps this could shed some light on the earlier discussion of frame cracking after rough use. >>
Columbus used to advertise that in their brochures but virtually all the big builders ignored those heat range recommendations and brass brazed their frames. A few, Benotto among them, advertised that they used silver but like Schwinn Paramounts*, the silver content was not high and the assembly temperatures were not much difference. The reality was that all these bikes performed similarly and obviously the touch of the builder was adequate to do the job..
*Schwinn stated that they used silver on the Paramounts, for all those reasons we hear from others (incl. Waterford later), but if you look at the brake and chain stay bridges you can tell immediately that low silver content joining material was used.. The filets are huge!