Hi Norris, and other interested framebuilders.
Interesting stuff re; fillet brazing........embarrassingly I can't say I have studied the work by the Taylor brothers in detail, I myself choose to use a flux coated rod [Eutectic 185XC] and yes it is possible to get the joint as smooth as possible, but I prefer to do it in one passage, without reheating, I use a No 7 nozzle. However I always finish off by sanding the joint, it really gives a finer sleek look to the frame.
And regarding jigs.........never used them, not at Bob Jacksons, or Woodrup's, and now at Thorn's I use a flat surface plate with some custom made attachments to hold the frame whilst it is tacked before fully brazing with no enforced pressure..............Oh and as for music, some of my best work as been done to the sound of 'Black Sabbath, Led Zep etc'
Cheers
Kevin Sayles Bridgwater Somerset UK
>
> As Dale has pointed out off-List to John, fillet-brazing, or
> bronze-welding
> as it is known over in the UK, is a technique that, like many other skills
> , needs practice to make good. There are however other considerations and
> p
> reparations that should be made before the torch and rod are even
> approache
> d to the frame's joints. Preparation makes perfect!
>
> I was lucky in being taught to braze and bronze-weld by the chief
> instructo
> r at the British Oxygen Company in London. Other than that his main claim
> t
> o fame was that he developed the manufacture of the "black box" flight
> reco
> rder containers, by welding them up in osmium. His party piece for his
> trai
> nees was to tear in half the aluminium foil container from an apple or
> plum
> pie - just think how thin those things are - and weld it back together.
>
> For the neatest bronze-welding we were taught not to use the standard
> brazi
> ng flux such as SIF-BRONZE, but to apply a special "antiporosity" one. No
> f
> lux would be applied to the cleaned up joint, but it would be applied
> durin
> g the welding process by dipping the end of the rod into the tin of flux.
> This type of flux helped to control the sideways spread of the bead, kep
> t the outer margins very straight and true, and limited the amount of zinc
> that would be boiled out of the molten weld material, in the event of the
> t
> orch's flame not being precisely set up. ie the oxygen/acetylene balance.
> W
> ith reasonable care and accurate settings of the gauges and the gas mix at
> the torch, very accurate and neat beads, with evenly spaced ripples, will
> result.
>
> To then convert the ripples into a smooth finish as Norman used to do, it
> i
> s necessary to take a small nozzle - I use a No1 - and to set up the flame
> very accurately. With as small a gas-balanced flame as possible - this
> show
> s as quite a tiny one with a miniscule blue inner cone, the flame is
> focuss
> ed on the weld with the tip of the cone almost but not quite touching the
> b
> ronze. The process is not a fast one..but once started it is and must be a
> continuous one if a smooth surface is to be the outcome.
> Once the parent weld metal has started to melt and a small molten pool
> is available at the tip of the flame, the flame is played and stroked f
> rom side to side and onwards over the bead. Because the pool, or "onion"
> of molten metal is so small, it is easily controllable. A steady hand and
> a
> good eye, and a reasonable amount of patience and practice will produce
> the required smooth and shiney bead.
>
> Remember always - you are in control of that torch and the molten metal at
> its tip...It's a very rewarding feeling.
>
> Oh....! and I always find that I get the best results if I have a piece o
> f peaceful non-intrusive music such as Beethoven's Pastoral Symphony,
> Elgar
> 's Enigma Variations..or even the lyrical Songs of the Auvergne playing in
> the background. And don't forget to wear you welder's tan leather
> skull-cap
> either...I understand from my recent research that many French frame=bui
> lders, particularly the constructeurs, used to wear the traditional Breton
> beret as they welded up their frames. If you are a smoker, try lighting up
> a Gauloise or Gitane cigarette as these particular brands are known to
> prod
> uce very long ash residues sometimes up to three centimetres in
> length,that
> cling to the end of the cigarette. The longer the ash,,,,the smoother t
> he finished bead.
>
> Norris Lockley, Settle UK
>
> Norris Lockley, Settle UK
>
>
>
> =0A=0A=0A