The tool used to make the Sumi Ink Painting below is a cola pen, pictured at left. It is literally cut out of an aluminum can. These instructions are from my notes from a class I took with Lisa Engelbrecht back in 2003. She now has a fabulous book called "Modern Mark Making", in which she talks about all sorts of funky tools, including this one. You can find out more about her and her book at www.lisaengelbrecht.com.
So, without further ado, here's how to make a cola pen:
1. Cut the ends off of a pop can—or "soda/coke/cola" can, depending on where you're from! :-)
2. Cut a square out of the aluminum.
3. Fold square in half, but don't crease it sharply.
4. Draw a sort of spade shape, or a shape that looks like the outlines of a solid number 4 (without the little serif coming out on the right of the vertical stroke). The diagonal stroke of the "4" shape should be slightly curved.
5. Cut that shape out and wrap around a pencil or chopstick.
6. Wrap some masking tape around the bottom "stem" of the "4" shape, as well as around the lower center of the spade. See the dark area across the wide part of my pen. That's the masking tape. This holds the edges together, while leaving a wide area at the tip for dipping into your writing fluid.
7. Depending on how big you want your strokes, you can play with how large you cut your shape; as well as the placement of that masking tape. I've seen some wrap the tape around the top 1/3 of the wide part of the shape. ("Top" being the area closest to the stem that is wrapped around the pencil.)
8. Smooth the edges of that slightly rounded edge with some crocus cloth.
It's easier than it sounds here. Really!