Question:
Why do I get "whispy things" under the fluorescence microscope instead of microtubules when polymerizing rhodamine tubulin?

Answer:
I have a few questions that might help you determine whether you are treating it correctly.

1. Do you store vials at -70°C?
2. How much MT cushion buffer (60% glycerol) do you add to the reaction to get 3 mg/ml? It seems like, from the message, that you add two volumes 4 µl to get 3 mg/ml. This would be 40% glycerol, which is way too high for proper polymerization. (This was the main problem).
3. Does the tubulin warm up before diluting? This would also make too many whispy like things.
4. What is the magnification on your microscope, are the whispy things actually MTs tangling with each other?