Sorries Gabriel, was pretty busy yesterday so I didn't get around to taking any pics. I have two different types of impellers, one for the 2" PVC where the 3/16" tubing slips right in. For the other tubing, I just used the metal rod from the MaxiJet impeller assembly to line up both the tubing and the propeller and glued them together with thick superglue gel. To prevent the metal rod from being glued also, I simply moved it around every few minutes to prevent the glue from bonding the rod and the propeller together. I know this is a pretty poor way of doing things but I was just concerned with getting a test propeller together. Ultimately I plan on using the 2" PVC propellers anyways, which the 3/16" tubing will fit perfectly inside.
Something to keep in mind if you're still looking for the 1/8" tubing, the inner diameter of the 1/8" tubing may be too small to fit your propeller rod through.