Well "contraflecture" who won the auction for the GIOS S/S frame might just have something a little different soon between his thighs. As Steve Willis pointed out Columbus did produce a tubing, not too long ago.. not actually stainless steel.. not actually a CRO-Mo.. but quite a witshes' brew in fact. The 1995 edition of Columbus' catalogue lists a series of tubing called "METAX", made from "Nicromox Steel" Are you with me so far? The frame decal went on to say that Metax is "corrosion proof Eco Concept" which of course explains it all clearly. Reading the technical specification for the tubing it is an austenitic / ferritic alloy with added alloying ingredients such as manganese, molybdenum and... nitrogen, the nitrogen acting as a"stabilising influence on the austenitic part of the mix.. In a handbook I have on working Columbus' tubes, the framebuilder is warned about the danger of any carbon, zinc or copper contamination in the welding process ie get you torch's flame set up spot on. TIG is a possibility. The advice recommends that the frame be painted after completion bt states that the tubes can be left bare.. so long as they are professionally polished, assuming that the construction has been "parfait" perfect.
Now I know why I never built many METAX frames.. and why not many other builders put the series in their repertoire.
Norris Lockley, Settle, UK