Check with your local community college. Most of them have metal shop
classes and all the ones I've seen can handle the 8' edge of a 4x8 sheet.

If push comes to shove and they won't let you have an hour or so on it, just
register for the class and punch out the first week of classes; you get all
your money back.

If you can't find one, I know Sierra College in Rocklin has one and I'm
faculty there.

Jim