Here is a video on Swirl water painting LW used a similar process but at a larger scale doing there Haze and Swirl lamps. Just remember to use a flat white primer paint first for better paint sticking and tape to mask the inside of the cap and base.
Thanks Bohdan. I have always been interested in this process, really fun and interesting video to watch. There was a guy here to was making some cool marble looking bases and caps. Wish Mathmos would do this with the Astro Baby it would look pretty nice.