In general, Jensen recommends the highest melting presolder that can work with any given alloy. Using the highest melting presolder gives you a technical advantage, in that your pre-soldered frames will be less likely to warp or distort during oxidation and opaque firings. Generally speaking, higher melting range solders will be more resistant to creep than lower melting solders. However, some technicians (particularly those who solder infrequently) may need a larger “window” between solder liquidus and alloy solidus.
SOLDER SELECTION EXAMPLE:
The recommended pre-solder for SENTRY is PWS. SENTRY has a solidus temperature of 1190°C, PWS has a liquidus temperature of 1150°C, leaving the technician about 40 degrees between the temperature that the solder will start to flow and the temperature that the casting will start to melt. If you have difficulty getting the solder to flow, you can usually use a lower melting solder. In the case of SENTRY, you can easily use P80 SOLDER which is completely molten at 1115°C. You’ll then have a “window” of 75°C between the temperature where the solder starts to flow and the temperature where the casting starts to melt. You may give up a little theoretical creep resistance in the framework, but it’s easier to get the solder to flow.
C&B Post Ceramic Solder: 650 Fine, 615 Fine, 585 Fine, 1400
Pre Ceramic Solder: LX, CPS, PWS, P80, spirit
Specialty Solder: Satellite
Ideal for: Use the solder recommended on the technical guide or package. The solders liquidus temperature must be lower than the alloys solidus temperature..