Mike you are quite correct in that assumption about mild steel being the safest thing-period. Also, another note on this, KOF as for on topic.I am quite certain without asking him that Peter Moon tig welds his stainless steel lugs(to construct the lugs).But the preparation would be virtually identical to what Herse and all would have done with mild steel. Only the welding,would differ because you don't have to have a tig machine to weld mild steel(correctly),clean coat hangars are fine.We have all done that a few times.But I wouldn't go so far as to say that they are better than the filler rods you buy from a welding store,cheaper though.Especially if you have a job with your name on your shirt.
Glad my name is on my shirt for welding rods and memory sake, Harris Spracher Waynesboro Va. hersefan@comcast.net wrote: Your comments bring back some memories... When I first became interested in frames, I encountered a few folks who were quite knowledgable of welding and brazing who were quite surprised that bicycle builders were quite worried about overheating. It seems that welding 4130 was quite common in the world outside bicycles. My guess is that perhaps in other welding applications maybe the wall thicknesses were heavier and a fatique failure from embrittlement is less likely. In the bicycle world, though, it seems that overheating really is something to be concerned with, at least to some extent. My thought, though, is that when welding the use of mild steel is the safest, such as for making lugs and bb's. If I'm wrong on this, please let me know. Mike Kone in Boulder CO
> 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
>
> --- hersefan@comcast.net wrote:
> > 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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