Chronology | Current Month | Current Thread | Current Date |
[Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
On Mon, 3 Jun 2002, John S. Denker wrote:
And there's no need. Most things that formerly were done
with mercury can be done these days in other ways, just as
nicely or even better:
-- mercury switch --> reed switch + magnet
or optical switch + interrupter
-- Hg diffusion pump --> silicone diffusion pump
or turbopump or ion pump
-- various explosive compounds --> other explosive compounds
In the past, people have repeated the Faraday Disk demonstration by using
electric heaters and Bismuth or Indium solder (Rose Metal, Wood's metal,
etc.) If you need a pool of liquid conductor, and if electrolytes aren't
conductive enough, then molten tin/lead can be used.
Unfortunately this alloy is fairly expensive, but a university lab might
be able to make up a batch. Also, beware of some of the low temperature
solder recipes which contain Cadmium.
http://www.belmontmetals.com/products/low-melting.cfm
I have a data sheet from Belmont Metals. It shows an alloy that melts at
136F (hot water), which is 49% bismuth, 21% indium, 18% lead, and 12% tin.
The lowest temperature fusible alloy I've seen mentioned will supposedly
melt at 30C (86F), but I don't know what it contains. That stuff would
be liquid during a hot day! I bet it's full of cadmium though.
Here are some alloy recipes:
Rocket Web Library: alloys
http://arocket.mid-south.net/library/Structures/Metalwork/alloys.html
Here's a place to buy small amounts of "Field's Metal" 144F alloy:
https://host2.4ua.com/scitoys/cgi-bin/shop.exe?page=store.html
Note that bismuth can be had from "environmental green" shotgun shells
which use bismuth pellets rather than lead.
(((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb@eskimo.com http://amasci.com
EE/programmer/sci-exhibits science projects, tesla, weird science
Seattle, WA 206-789-0775 sciclub-list freenrg-L vortex-L webhead-L