I am going to look into this situation that happen to me tonight. I was bead blasting with medium fine (100-130) glass beads some aluminum parts in my blasting cabinet and when I was done I decided to bead blast my custom wedding band made from high grade titanium. It was looking like the wear that 10 years of marriage can do... 
I userstood why I was seeing the sparks that were generated, but the static electricity that was generated on a fairly high humidity day was amazing! I was shocked through my rubber gloves as well as were the cabinet touch my legs... Wow didn't expect that when I was getting no effect from the aluminum.
I am sure it is nothing more than duplicating the action of a simple Van De Graaf generator... But I was truly amazed by the large static potential generated by only the titanium.
Scott
One of the worst things to do while blasting is to hold the object where you're blasting the glove with a strong stream of media. As you stated, a static build-up is created. Just keep your arm in CONSTANT contact with the blast cabinet while blasting, and you won't build up a static charge. Your body is like a giant capacitor, storing the static charge and just waiting for the potential to find a ground, and ...........ZAP!
Isn't titanium and magnesium cool to bead blast???
Some carbides do the same thing, only not so pronounced.
