I just thought I would share this find with other prop builders here.

http://www.blucigs.com/products.php

This company makes electronic cigarettes. A small heating element connected to an airflow sensor vaporizes a small amount of propylene glycol, producing a puff of water vapor. It occurs to me that an atomizer this small could be mounted in the barrel of a prop blaster to produce a small amount of smoke every time the trigger is pulled. The airflow sensor could be shorted out so that the unit produces smoke whenever power is applied, and the power source could be the battery that drives your blaster's soundboard or led. Alternatively, the airflow sensor could be utilized as-is if the prop blaster had some sort of small air pump installed, like the sort of thing you find in a $1 squirt gun. I don't have any blaster projects planned at the moment, but I thought someone else might be interested. The atomizers are sold in pairs for $10, making this a cheap prop gun upgrade. Let me know what you think.