FWIW, Ross was using "salt-bath brazing" for their cheap frames 25 years ago...
the process worked only with "gas pipe" quality tubing - when they tried it once with a triple-butted Tange tubset, what came out resembled a pretzel more than a bike frame. This according to Tom Kellogg, who was building their Signature frames at the time... I have a Ross brochure from 1980 that shows the "salt-bath brazing" line - looks like a foundry!
Duncan Granger
Mountville, PA