By James Morikawa
11 January 2007
I will attempt to describe how I go about dehydrating (drying-out) the inside of the tubes. I want to "evacuate" as much of the moisture and air out of the tubes, prior to filling and sealing them with argon-gas. I will be using a vacuum pump to pull and hold a high-vacuum — a process of the Air-Conditioning/Refrigeration Repair Industry called, "Evacuating", or "Evacuation".
I've adapted some of my refrigeration tools to my framebuilding. I will "evacuate" the tubes for 1 to 2 hours. I then back-fill the vacuum with Argon gas, the same stuff I use for Tig welding.
These are the "brass sealing plugs" I will be using to seal the tube-holes. They are made from short lengths of brazing rod. I grind a taper on one end.
Immediately after a tube-hole has it's argon flow stopped and removed, a brass plug is tapped in. The plug is then silver-brazed to permanently seal it. The argon pressure in the tubes are at atmosphoric pressure.
Above are the silver-brazed plugs on the rear-triangle. The process is the same for toptube and downtube.
I got to smooth out the rough plugs:
Above is a picture of a smoothed out plug.
A note: these hole are always situated at the bottom-side of each tube and stay.
And thus, I assume I have argon-filled, and sealed tubes. As long as a tube doesn't crack, or somehow develop a leak, there shouldn't be any internal oxidation. There's a possible drawback — If a tube should lose it's sealing quality . . . it will be prone to internal-oxidation . . . something that would be very uncool.
I may no longer be doing the above. Awhile back, I began to feel the benefits were too minimal, to justify the work and labor involved. I think I can save a lot of time and labor by keeping the tubes "vented", and coating the internals with a protective coating such as "JP Weigle's Frame-Saver". A process that worked well for me in the past.
That's all I got to write. Good night.