: BTW, anyone know where I can pick up a used small blueprint machine on the
: cheap?

Why not build one?

You need a roll supply for the blueprint paper which is baffled so it is not exposed to light. That's not too hard to do. You can cut sheets of material from this before exposing them.

You can make a large, flat, exposure area from a sheet of 1/4 inch plate glass.
Suspend UV rich halogen bulbs above this for your exposure. Or you can get photoflood bulbs from a camera store.

Some people use a 4 foot flourescent fixture and UV rich bulbs in that.

For the "dry" process you use a "diazo" material which uses a light-sensitive nitrogen dye that is processed in in the fumes from ammonia. This is a positive to positive process (like a xerox photocopy) which would probably be good for reproducing your plans and drawings. Get good ventilation.

The "wet" process uses either silver or iron based compounds. The iron based materials are cheaper and are developed in plain water. You could use a tray for soaking preglued wallpaper and slosh it through, or make a large flat tray from plywood, fiberglass, and epoxy resin. Should be a nice simple stitch and glue project

You can make your own blueprint paper for this process, too. Only two chemicals to mix in water. You just paint this on sheets of paper with a foam brush or roller and let it dry in a dark place. If you want, I'll post or e-mail the recipe. The image is quite a nice blue -- and very permanent -- so try to avoid dripping the mix on anything expensive.

PGJ