I might add, use Muffler Cement and not regular epoxy.? Epoxy
can't handle much heat.? The muffler cement used will be the last
time the cap will ever come loose again.
Lee, w0vt
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Similar to Lee, but I just use my normal solder. ?
Never had an issue after but¡ I never had a tube that hot (I
guess).
? ? ?Frank Krozel
? ? ? ? ? ?KG9H
Life Member, ARRL
? ? (630) 924-1600
On Jan 30, 2025, at 4:54?PM, Leland L. Bahr via
groups.io
<w5drc@...> wrote:
First off, I glue the cap back on the tube with
Muffler Cement sold in a toothpaste tube at a local
Auto parts store.? Then I use normal electrical
solder.? I have never had my re-soldering on a tube
melt.
Lee, w0vt
On 1/30/2025 3:48 PM,
Michael Smith via groups.io wrote:
I¡¯m looking for anyone¡¯s experience in
successfully soldering an anode high voltage
cap-contact on a final tube. ?Particularly, being
that the typical maximum bulb temperature of the
tube is 500 degrees F, most commonly available
modern solder alloys have a melting temperature
around 430 degrees F, that is the non-leaded
alloys; I expect adding lead would decrease the
melting temperature further. ?Industry defines a
96.5% Sn - 3% Ag - ?0.5 % Cu alloy as ¡°High
Temperature Solder.¡± ?With the anode in direct
contact with the bulb sitting centrally just above
the heater, and heat rising, I would expect this
solder would melt during normal operation due to
the heat being constantly added. ?The tube
manufacturers used some kind of solder to
electrically bond the anode wire that penetrates
the glass bulb to the HV cap-contact: what alloy,
I know not. ?What has been your experience in
re-soldering the anode HV contact on these final
tubes? ?Successful to date?
?
Thank you.
?
73, Michael Smith, N4KZO
