[MENTION=104721]CuttersRidge[/MENTION]

Inexternal brazing is a euphemistic phrase for production furnace brazing, a process that has been used on bike frames, metal furniture and myriad of other consumer products for many years. It's a cheap manufacturing process but it usually works satisfactorily.

In the early 80's Motobecane, Peugeot and Gitane introduced a lot of "lugless" lower priced models to compete against Asian made lugged frame models coming into the European market.

By 1983, all of Motobecane's models in the US catalog had lugless frames except the Grad Touring and the Team Champion.

"Preforms" made of brazing material are placed inside and outside of the tubes. The tubes are either furnace brazed or held in an automated fixture and machine brazed; the brazing material melts and forms a lugless bond.

First picture is Motobecanes Inexternal process, second is Peugeot's




For me, those kinds of lugless frames have lost any semblance of a hand crafted product. The frames are not much more than Huffys or other department store bikes with Columbus tubing rather than gas pipes.

I've never seen a failure in one of those 1980's French lugless frames but I'd heard that Trek had problems with some of the Gitane bikes they were marketing back then.

verktyg

Chas.