That doesn't really explain the large number of aircraft, racing cars and motorcycles whose superstructures were made of chrome-moly tubing and assembled by oxy-acetylene welding.
Perhaps the critical difference is actually the wall thickness
of the tubing. There might also be a question of which filler
rod to use. When I was doing this sort of work, we were told
that metal coat hangers were actually the best filler rods for
use with chrome-moly tubing. Perhaps that also only works well
with greater wall thickness.
Cheers,
Fred Rednor - Arlington, Virginia
> Well sort of.....
> Some old frames such as Rene Herse and Alex Singer had
> handmade lugs which were made by (I'm pretty sure anyway) gas
> welding. Tubing was cut, mitered, gas welded together, then
> reamed out and cut, and voila - a lug or bb shell. This was
> often done when custom angles or sizes were needed.
> The reason that such welding works on these parts but would
> be a dissaster on a lightweight frame is that the material is
> different. For welding, a mild steel is used. Steels with
> higher carbon content become brittle (actually when cooled,
> the damage of overheating really occurs on the cooling side
> of things).
> Mike Kone in Boulder Colorado
> -------------- Original message --------------
>
> > David Benson brings up an important point to consider - in
> the thirties it was a
> > standard process to flame weld the various types of tubing
> that were used in
> > aircraft construction. A filler rod was employed and the
> results could be very
> > nice indeed - depending on the skill of the welder, of
> course. I discovered this
> > in an old book on aircraft welding from @ the late 1930's,
> or maybe it was the
> > WW2 era. If I recall correctly, the gas of choice was a
> Hydrogen/Oxygen mix at
> > low pressures. Like many welding processes it was not easy
> to master, and the
> > problems with getting a reliable joint to survive aviation
> service is what I
> > believe led to development of the TIG process during WW2.
> >
> > Enough with welding history - but it makes me wonder if
> some of those early
> > lightweight frames Mick and Norman refer to might have been
> STEEL fillet welded
> > with a torch ? They would probably have been Reynolds HM
> (531's predecessor) or
> > Accles and Pollock (aka Accles and Bollocks)Kromo - both of
> which would have
> > worked with the process. I imagine that these frames were
> produced as a means to
> > save money on time and materials compared to a lugged
> frame, and steel filler
> > rod has always been cheaper than brass or bronze.
> >
> > It would be interesting to see if anyone remembers
> repairing or repainting any
> > of the welded/bronze welded frames in question, and if they
> recall what was used
> > to stick them together.
> >
> > Mike Fabian in San Francisco
> > who wonders what exactly holds those modern plastic things
> together ?
> >
> > _______________________________________________
>
> _______________________________________________
>
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