In this question I was told that I should use silver solder to connect the heating element to the power supply.
(I was also told that a ceramic extruder head was the way to go, but I'm working with what I have)
I bought two types of silver solider from Radio Shack:
- 96/4 Silver-Bearing Solder, Lead-Free 0.62" diameter.
- 62/36/2 Silver-Bearing Solder, 0.15" diameter.
Is there any reason I should use one of these over the other to power the heading element of the J-Head extruder?
The first is not suitable. ASTM96TS Sn96Ag4 has a melting point of 221–229°C according to Wikipedia. Pb96Ag4 would be OK, but that is not lead free so doesn't seem to match your description.
Sn62Pb36Ag2 is an ordinary expensive electronics solder (but not lead free), with an even lower melting point.
You need to find a high temperature silver solder, with a melting point of about 305°C (which confusingly might be a soft silver solder), for example one of these. Hard silver solders melt at 600 degrees, that would be excessive in this application.
The nomenclature 'silver solder' came about before lead-free electronics solder was introduced, since when more alloys containing silver have become popular as general purpose solders.