A&B: You might want to check to see if your blast media is contaminated. Also give us the color, cure temp and time.
C: Faraday cage effect is when you spray charged powder into a corner and the charge repells back because you have two positives in contact with each other resulting in no coverage in that area. Think of it like this...oposites attract.
D:
Looking to purchase pro type gun from caswell have questions
I like this system alot as you can tell. I have an early released system which is not as good as the current system, but it's still a great system. There are other pro-level cup guns out there but for a small shop looking for a good gun at a reasonable cost I recommend the Alpha.
E: I degrease them then bake em or send them to a local parts store to have them hot tanked.
F: I do not ever buy powder from ebay. If you buy from a reputable supplier like Caswell your purchase is garanteed. Powder will last a long time...If it's stored properly. If you buy it from ebay how do you know who is selling you powder or where it comes from? As for type it really depends on the task at hand. I suggest you go to the home page and hit the powder coating link and check the lower right of the page and read the write ups on the powder types. The advantages and disadvantages should give you the info you need.