RE:GREY COPPER - OMGWhy do you not just reach out to Alex with your questions? He's very approachable and usually responds quite quickly. As far as the XRF goes its not really useful in this application (have my XRF cert). It's only going to tell you what the test surface only material composition is, at a single point no larger than say 6-8mm circle. Gun also has a difficult time with iron's and carbon so you'll get a dilution effect of other elements. Only true way to know material composition is to assay it.