Advice needed on modeling project

snipped-for-privacy@aol.com spake thus:

I'd set up a jig to clamp the tubing flat on the work surface, something like wooden board with two pieces of 1/8" masonite, one on either side of the tube to secure it. Nail or screw one piece securely, lay the tube next to it, then push the other piece against the other side and screw it tightly against the tube (drywall screws ought to work well here). This should hold the tube from moving.

Now you can use a good sharp razor saw to cut the slot. Work slowly and carefully; you ought to be able to cut a very straight slot. You'll only be able to use the top inch or so of the saw. Hint: use candle wax on the blade to lubricate it so it doesn't bind.

There is a technique I learned from model rocketry. To make a lengthwise mark on a round rube, you put the tube in a drawer front. Actually all you need is a suitable piece of angle. In your case get a piece of styreen (or brass) angle (it will need to be real small). Then score your slot with a sharp hobby knife -- probably a new blade. It might be easiest to create a jig with some pieces of 1/8" brass bar stock, with a couple of pieces just under 1/16".