The last contractor I worked for had a Panasonic 15.6v saw. The saw worked really well when the blade was new. It didn't grab the metal at the end of the cut like cutting by hand does. The smell of burning/melting plastic was the only bad side effect, but it didn't last very long. Otherwise, a hacksaw with a 32 tpi blade, holding the sealtight as close and solid as possible to the cut.
