As per Rylan request, I have started this new thread to show my progress in testing Variable Capacitance as a viable means of real time Z axis feed back.

The variable Capacitor I used was made out of a length of 1/2" PVC pipe with a strip of Aluminium tape on the outside then wrapped with electrical tape to prevent shorting, the tape was then sealed with several layers of spray paint, the cathode is made up of 1/4" steel rod that has been covered with heat shrink tubing again to prvent shorting. the whole thing is held together by two custom made end caps made out of Poly-Styrene.

the experiment shown in the video consists of:
-6 Dixie cups with 50 ml of water
-3 of the cups had water that was left out for one and a half weeks to evaporate any Chlorine and to allow any disolved solids to settle
-the other 3 cups had water that was drawn straight from the tap just prior to the experiment only allowing enough time for it to reach room temperature
-each set of 3 cups had one cup refrigerated for an hour and a half, one cup that was microwaved for 40 seconds, and one that was kept at room temperature
-Each sample was tested for two minutes each (video has been sped up 2x to decrease video run time)

the purpose of this experiment was to show that simply making a variable capacitor will not make a reliable Z axis feedback system, however over the course of time I plan to build a sensor array that will allow the system to compensate for all the variables, making it 100% reliable