Re: Soldering an Anode HV Cap-Contact Back In Place; Solder Alloy Used?
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If it were me, I might go the mechanical/non-solder approach. ?Using something like a Fahnestock (sp?) clip or other device for the connection. ?Back in the day there were several RF amp tubes that didn't use soldered caps.
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 kg9hfrank@...
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
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