I've been gathering brass plumbing fittings for casting, but I was wondering about the differences between old plumbing, and modern lead-free brass. The old stuff is standard 85-5-5-5 I believe, but modern lead free brass uses bismuth (in addition to zinc and tin) to replace the lead. This effects torch soldering for pipes (new stuff doesn't conduct heat as well so takes a little more care with the torch), but how would it effect casting? Is it possible to tell the difference in color? I've heard of yellow versus red brass, but this isn't ornamental stuff so I wouldn't think the cheap brass is usable in plumbing. Is it fine to mix? I would think the end product would just split the lead content with bisthmuth in amounts depending on how many of each kind I have.