Rather than hijack Wendys post about the poor quality pcb material she was using for screening, I use tin that is recovered from 4L cooking oil containers.
At least one brand Downunder comes in comes in tins roughly 5" square and about a foot high, with completely smooth sides, rounded corners and a single joining seam in one side.
Yes, a little bit of messing about cleaning them, but easily done with a bit of dishwashing detergent and hot water (before you cut it up
).
Bit of flux and a hot iron does the job easy enough.