ABSTRACT
A jewelry maker discovered that adding copper to gold reduces the melt point of the resulting mixture. This led to a breakthrough in goldsmithing, because small decorations could be soldered to a main element of pure gold with a copper-rich alloy. The copper blended in with no noticeable loss of luster in the finished piece. This is a fully replicated design on the pure metals and their binary blend. If the blends are simply retested for melt point without reformulation, the only variation is due to testing, not the entire process, and error will be underestimated. The coefficients for the main effects are the responses for the purest “blends” for A and B. The negative coefficient on AB indicates that a combination of the two components produces a response that is less than what industrial experimenters would expect from linear blending.
