Re: [CR] Ciocc headtube rebuild

(Example: Framebuilding:Brazing Technique)

From: "Scott L. Minneman" <minneman@onomy.com>
To: 'Bianca Pratorius' <biankita@comcast.net>, <classicrendezvous@bikelist.org>
References: <fc94d043da4dd2705d95fe70233afd8c@comcast.net>
In-Reply-To:
Date: Wed, 21 Oct 2009 13:47:30 -0700
Thread-Index: AcpSgda2tFDOjbX3STimkZZLhN1y3QABi7+g
Subject: Re: [CR] Ciocc headtube rebuild


He certainly wasn't going slowly or being super-careful, but you *do* have to get the whole of the joint into a liquid state (and, as Brian points out, the remelt temperatures are higher than the original brazing temps (because the filler material's melting point depressants have dissipated during/after the initial brazing)). The bright red I was seeing looked like the high end of the red range (1500-1600 degrees), but it's hard to tell without being there. Reynolds says 1562-1742 maximum for 531-class tubings. The part of the tube that got really hot was near the end, so it'll be 1) in the thicker, butted part of the tube, and 2) be back inside a lug after the repair.

A fair amount of flux on the repair sites is pretty evident at 1:08 into the video.

I wonder how/where the original head tube was damaged.

Scott Minneman San Francisco, CA, USA

-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of Bianca Pratorius Sent: Monday, October 19, 2009 1:03 AM To: classicrendezvous@bikelist.org Subject: [CR] Ciocc headtube rebuild

In this video, it sure takes a lot of heat to get the old headtube out. Does that amount of heat exceed the amount that was needed to braze the original? The top tube was totally glowing red hot when he was done, Did the frame get damaged in the process?

http://www.youtube.com/watch?v=SJHwPqn2jY0

Garth Libre in Miami Fl USA