John Butler, a process engineer in Stuller's research and development department, has 23 years of experience in multiple areas of metal fabrication. John's time in these departments is what gives him a unique insight into what is needed for a metal alloy  to be both practical and innovative. It is this insight coupled with his passion for sterling silver that led to the creation of Continuum Sterling Silver.

John's interest in sterling silver began shortly after the start of his career at Stuller. Inspired by Earnest A. Smith's book, Working in Precious Metals, and motivated by his supervisor, John started creating silver formulas with and without grain refiners and oxide inhibitors to learn all he could about what was possible. However, at this time in the industry, silver was not as popular as it is today, so John's formulas often didn't go very far.

It was his unique experience in die-striking that inspired John's idea for what characteristics a perfect sterling silver alloy would need. As part of metal fabrication, more emphasis was placed on the way metal could be manipulated. Processes like hard phases, annealing and heat-treating gave him greater first-hand knowledge on the importance of a metal's properties.

Taking his insight back to research and development, John began to fine-tune his silver formulas. Dennis Busby in Stuller's casting department challenged John to make a harder sterling formula. The duo discussed the importance of the metal's hardness and tarnish resistance. A sample cast was created and analyzed after each formula change until the recipe was just right.

The main obstacle they faced with the new alloy was retaining silver metal qualities, as only 7.5% of the composition could be other metals. This made for a small margin of error, but one John was sure they could overcome. Two formulas showed the most promise, but were still shy of the ultimate goal. Inspiration struck, and John decided to combine these two new formulas in a 40%/60% mixture that was labeled SX-8 (Sterling Experimental Eight Elements). When cast, the alloy hit every goal and preformed better than expected.

With the renewed sense of excitement, John took the new metal alloy to Stuller's metallurgist Shan Aithal, PhD, for analysis and the silver alloy now stands as the most tested metal ever produced by Stuller. Called Continuum Sterling Silver, John Butler's idea for a tarnish resistant sterling silver alloy that would cast harder was finally realized.

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