Sock Doping
Paint braze
This bike caught my eye the other day. It's a Canadian built (according to the stickers) low end Peugeot mountain bike. I'm guessing a 1990s vintage. Any body know what the joining process is here? I assume it's brazed, but I've never seen a sweat braze on the main tubes before. Is there an internal lug maybe? All the main tube joints look like this.
Martin Tweedy
Administrator
Re: Paint braze
It's brazed from within using some sweated smelter brass ring thingy that a furnace melts when the joint is at temperature. With enough volume they can calculate the amount of filler, the heat cycle, and the time needed.Originally Posted by Martin T
Sock Doping
Re: Paint braze
So presumably there's a good sized fillet inside the tube and the tubes are probably relatively heavy gauge. I'd like to take one apart and look inside.
Martin Tweedy
Rolls with style
Steher 10000
Re: Paint braze
That's how Brompton makes part of their main triangle.
As they can miter the tubing square in respect to the hinge, it saves lots of time. They still braze the rest of the frame, which is remarkable for a mass-produced bike.
Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London
"Caron, non ti crucciare:
vuolsi così colà dove si puote
ciò che si vuole, e più non dimandare"
In the drops
Re: Paint braze
I repaired one like that recently - TT snapped at the HT. The HT had a spigot on it, which the TT fitted over then was brazed, and the spigot snapped off. Not the best construction method, but cheap.
The Brompton hinge joint is a bit different - with that, the main tube is socketed into the hinge, it's basically a big lug.
Double Butted
Re: Paint braze
Eric alluded to the Peugot's. I had one of those, bought it new in '83 and rode the crap out of it until I was hit by a car whilst riding it in '91. As a result of the crash, the main triangle was bent quite severely, but the joints held fast , to my surprise.
Alistair.
Steher 10000
Re: Paint braze
Actually, my crappy single-speed (hipster-mocker) was based on a Peugeot frame of that kind
Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London
"Caron, non ti crucciare:
vuolsi così colà dove si puote
ciò che si vuole, e più non dimandare"
Sock Doping
Re: Paint braze
OT... but my first "real" bicycle was in that catalog. I bought the Galaxie with the money from my first job and rode the hell out of it for 2 years, till it started creaking at the BB and got traded in under the recall for the triathlon. Sigh. Still kinda miss that flexi frame... Sold the Tri in the around 2000. Don't miss it much.
dave
My name is David Moeny
Sock Doping
Re: Paint braze
Wow, that's impressive, the tubes are cherry red a good three inches from the BB. Tim Isaac told me of the automated brazing they did at Trek. Must be very similar to what they have pictured here.
Martin Tweedy
Rolls with style
Re: Paint braze
Some of the big Japanese firms did this sort of brazing with internal pre-fills and lugs, too. Pretty cool.
In the drops
Re: Paint braze
Raleigh did too - the old Bicycle series by York films shows it beautifully. Tubes with brass rings plugged into the lugs, the whole BB shell or head tube put into a brazing hearth, all melts together.
Then a surface table and a big bloke with a scaffolding pole to make it straight ;-)
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