Originally Posted by
Dave Kirk
I got you - I hadn't thought of it that way.
How does the fact that there is a partial vacuum in the tube affect things? When the tube is heated the air greatly expands and comes rushing out of the small vent hole that's been drilled in the tube. The vert hole is then brazed shut while the tube is of course still very hot. That makes me think that that there is a partial vacuum in the tube.........is that right?
I've been heating up stays and blades and sealing them while hot for more than 25 years and not once have I seen any corrosion even when I've taken a 20 year old fork and cut it open. It looks the same as it did when it was brazed shut.
Cool stuff.
dave
I didn't think about the heated air expanding and leaving you with a partial vacuum. Doesn't change my argument except that the dewpoint will go down with the lower pressure. I don't have the calcs in front of me for that and am not about to look! But I will guess the dewpoint will now be well below zero F; maybe a problem if you ride in Antartica.
Ben