The bars are the essence of the sound, and the true quality of TreeWorks' chimes is in the color of the sound. We never paint, tint, dip, anodize or plate the bars, (since this adversely affects the sound). Also rejected are stock, off-the-shelf, aluminum bars. TreeWorks uses only custom mill runs, certified to spec and quality tested. The alloy is an aluminum/titanium composition that is T-6 tempered at 350°F for 8 hours. Tempering provides a more consistent grain structure (at the molecular level) and imparts the clear, distinctive sound that is TreeWorks' alone. Next, the bars are cut and precision drilled followed by polishing that bevels the edges to minimize friction against the cord. An art unto itself, the chimes are tuned by ear, with a gradual change in pitch, one at a time, bar by bar. No preset, assembly-line cutting.