If I remember correctly Xion, way back when I was an apprentice.
.050" is 18 gauge, which is 1.4mm.
If you are just cutting straight lines then try cutting the ali with a very sharp knife, like a Stanly knife and straight edge.

A bit like the perspex. After 2-3 hard cuts you should either be threw it or really close. Then just bend along the cut, keep flexing and it will brake.
Will need a quick file to clean up.