On Sun, 2003-01-26 at 08:32, Ken Hunter wrote:
Hi James,
Thanks for the informative post on the Capillary tube usage.
I don't know much about those things but I'd have to guess that the
capillary tubes I have are about 6-8 feet long (in a 3 inch dia
coil), maybe 1/16th inch OD and have a hole so tiny that I can't blow
air through them. I can take some photo's later but doubt that you'll
be able to see anything.
The 3 compressor units came on a frame with my 3 diffusion pumps,
valves etc. and 2 of thecapillary tubes were broken off at the point
where they were (looks like) soldered into the expansion chamber. I
haven't taken them apart to see what's inside but I imagine just a
couple inches of the capillary tube is sticking into the chamber.
Thought I could re-solder (maybe have to silver solder) the Capillary
tube back into the chamber and give it a go to see what happens. I
think I have a photo of the valves that also shows the compressors...
Yes - it is necessary to silver solder. If you just use a tin lead (or
whatever the newer version is) you run a severe risk of failure. Silver
solder done well has a tensile that is higher than your base material
where regular tin lead (I think the new version is zinc tin???) is
considerably weaker (about 5000# tensile if my information is correct
(it was for 37% Sn solder)).
I'll need to find a set of A/C gauges to give it a try. Interesting
that you said just to give it a shot of freon... I gather the idea is
to get the maximum pressure differential across the chamber while
still delivering a compressed liquid to the chamber to be expanded.
I'll try to get some measurements of the Capillary tubing and some
photo's this week if it get's warm enough to get outside to the barn.
There sure is a lot to learn.
Maybe I should introduce myself. I am a machinist with a fair amount of
welding experience that also likes to tinker. Astronomy has been
something that I have wanted to get into for a long time so I am
gathering information and we will see from there.
Has anyone here silvered a mirror and then coated it?
Just wondering how something like that would work out.
Darald
