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RE: annealing Primaries and Copper Tubing - a correction
Subject: RE: annealing Primaries and Copper Tubing - a correction
Date: Thu, 24 Apr 97 05:48:39 UT
From: "William Noble" <William_B_Noble-at-msn-dot-com>
To: "Tesla List" <tesla-at-pupman-dot-com>
one error - there is no need to let copper, silver, or gold cool slowly
after
annealing - only steel requires this (because of the carbon atoms in the
iron
matrix). according to my 1939 edition of the handbook of chem and
physics,
copper melts at 1083 C and boils at 2310 C (and it says it cost 35 cents
per
pound in 1917 but only 11 cents per pound in 1939) I was trying to look
up
the annealing tempeture for you and I can't find it anywhere.
anyway, while looking in the handbook, I found a table of spark gap
voltages
(ON pg 1517 if you have the same book) - the table goes from 5 to 300KV,
and
shows the gap voltage for needle points, and spherical electrodes of
2.5, 5,
10, and 25 cm. of possible interest here, :
KV 2.5 ball 5 ball needle
5 0.13 0.15 0.42cm length of spark gap
10 0.27 0.29 0.85cm
20 0.58 0.60 1.75
30 0.95 0.94 2.69
50 2.000 1.71 5.20
100 4.77 15.5
300 54.7
according to another table, lowering air temp increases the gap length,
as
does increasing air pressure.