I finally got up the guts to try aluminum. I can’t call it successful yet, because it’s actually still going right now. But it looks like I may have an AR 15 shaped bottle opener in a few more hours. https://youtu.be/mfR2ZrrR1z8
Looks good so far, once you have a successful Al cut under the belt you can start pushing the limits. Or be a sissy like me and just leave well enough alone…I push it in wood but just go slow and steady in metal.