On Fri, Dec 27, 2024 at 01:26 AM, Richard Kelly wrote:
understand the potential issue with the silver deposit ceramic strips and have
electronic solder to hand that is 95% Tin, 3.8% Silver and 0.7% Copper
According to Tektronix (back in the day)...
The solder they used... for the metalized ceramic strips (the notches were metalized with silver.. and dip coated with the solder)
The solder they used was 60% tin, 37% lead, and 3% silver.
The flux used was rosin.
Solder with 60% tin, 37% lead, and 3% silver has a melting range of approximately 179–183°C (354–361°F).
This composition is close to the eutectic solder alloy of 63% tin and 37% lead, which melts at a fixed temperature of 183°C
Eutectic solder... or near Eutectic solder... melts more fully... and solidifies more fully, in a shorter temperature... and time... range than non-eutectic solder.
That's good for a couple of reasons.
With 63/37 the silver can dissolve, to a small extent.
Most of the silver loving part of the solder is the tin.
More silver would get 'dissolved' at higher soldering temperatures... and times
So lead free, " 95% Tin, 3.8% Silver and 0.7% Copper" solder would not be 'ideal.' ... more on that later.
Anyway... I reckon the concern was dissolving the silver... sufficiently... from the ceramic strip notches... causing mechanical instability... in the soldered joint... supported by the notch... of the ceramic strip.
So, when using these old 500 series... with the ceramic strips... shipboard... or airborne... the military types would have scrutinized that... for reliability.
Anyway... I reckon further... that unless you are gona take your ceramic strip series 500... for a ride on New Sheppard... or with you and Elon (hopefully) to Mars...
I wouldn't worry about it.
--
Roy Thistle
