On Mon, 11 Jul 2005 08:34:50 -0500, John T
wrote:

Using a laser cutter changes the temper of the aluminum along the edges
of the cut. Perhaps not a big deal in a instrument panel, if it isn't
structural, but it is on a wing rib or other structural part.

A waterjet cutter can do the same thing, but you don't have to worry
about the temper. It will leave a slight burr, but nothing that can't be
dealed with simply.

A plasma torch properly set up can cut a hole in thin metal without
scorching the adjacent paint, but it takes a good set up and lots of
practice. They are fast. this would not be my choice for a first
timer.

I've cut sheets of white painted "barn metal" with a smaller self
contained unit. After being used to a torch (not on barn metal), it
took a bit of practice to get used to the speed (moving fast enough)
to do a good job. If the paint started to feather, or discolor along
the edge of the cut I knew I was moving too slow.

On a panel you'd want to build a fixture to move the tip in a circle,
or use a wood template. Wood works just fine as the plasma will, or
should be at least a quarter to half inch away from it.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

John