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SOLDER DATA
Once I had the karat gold data, my next step was to collect thermal data on 129 commercial solder compositions produced by different manufacturers. The solders were grouped according to karat and color, and further segregated as cadmium or non-cadmium alloys.
The solidus and liquidus values were determined for each individual solder with the same testing procedures used for the karat alloys. The significant value in this case was the liquidus temperature, as we are basing the scale on the temperature difference between the solidus of the karat metal and the liquidus of the solder.
Though there were temperature range differences noted between the cadmium-free and cadmium-bearing solders, they were grouped together in the final charts: The important relationship is between the karated metal and solder used to join it, not the solder formulation.
The relationship between the liquidus temperatures of the solders when grouped by color followed that of the karated alloys. The liquidus range of the 10k yellow solders extended from 1,275°F to 1,475°F (691°C to 802°C) and fell within that of the 14k yellow solders, 1,165°F to 1,540°F (629°C to 838°C).
The 10k and 14k white solders followed the same pattern as the yellow solders, with a slight inversion. The liquidus range of the 14k white solders extended from 1,280°F to 1,570°F (693°C to 854°C) and fell within that of the 10k white solders, 1,260°F to 1,570°F (682°C to 854°C).
In the 18k solder family, the white and yellow solders fell within a similar liquidus range, extending from 1,255°F to 1,625°F (679°C to 885°C).
The next step was to combine the graph for the 10k and 14k yellow alloys with the graph for their respective solders. There is a close clustering of solders and alloys around the top of the respective temperature ranges, but only one 14k yellow solder has a liquidus temperature above 1,510°F (821°C).
On the similar graph for the white alloys, there is a wider separation between the solidus temperatures of the alloys and the liquidus temperatures of the solders. The lowest solidus temperature of this alloy group is 25°F above the highest liquidus temperature of the solders. This was the only grouping where the solder and alloy temperatures did not overlap.