Several years ago a EAA member was building a four place experimental with
4130 as the airframe , the gentleman either couldn't or wouldn't learn to do
GAS welding and he ask the FAA if he could braze the structure together ,
FAA said that as it was under the experimental category and they could not
prevent him from brazing his four place bird together but they would like
him to make some samples to proof test his idea , samples proved his concept
and FAA gave him a green light , I think the filler rod was Eutectic FC16 ,
I did get a couple samples of the filler and made my own samples of 5/8 X
..035 4130 , tubing bent and finally broke after great load was applied , no
failure in the filler , only adjacent to it , the problem with this material
is that it uses a Flux coating and some of it is going to get inside the
tube and the stuff will corrode.
Phil
wrote in message
...
On Dec 28, 2:57 pm, wright1902glider wrote:
the author
seems to think that 4130 cro-mo steel can't be welded with an oxy-
acetylene torch.
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Pure bull****. Indeed, for the stresses encountered in bicycles
(which is what he's talking about) there are any number of BRAZING
compounds that yield joints stronger than than normalized 4130.

O/A does just fine airframes... and for bike frames.