ive seen these before and thought about trying them instead of ice in a tube... thoughts? http://www.thinkgeek.com/product/ba37/ you can get them in a variety of sizes and some with rounded edges.
i actually have whiskey stones like those that my girlfriend gifted to me for the exact reason to use with my water piece. i had come across them in the store and pointed them out, saying that they reminded me of Steele Concept's glycerine cubes. turns out that she bought them for me for christmas. i've used them a few times here and there with my straight tube and they definitely help with cooling the vapor down. i'll try to use them tomorrow and keep track of how long they stay cold for. i would safely bet 30-60 minutes but that has a lot of factors like the ones that Steve mentioned on his thread.
Initially I was thinking of using whiskey stones in my design. After extensive testing they simply do not compare to the glycerin cubes. They do not get as cold, nor hold cold nearly as long as the glycerin cubes seem to. This is unfortunate as they are cut all over the U.S. and very affordable. My gf had a smaller prototype of my tube I had made and we used the stones in that one. She definitely noticed a big difference when going from stones to cubes, as did I when using her unit. Brookstone also sells these cubes as drink chillers. If you have one locally you can also try there.
just used my whiskey stones with my Left Coast straight tube. i'll definitely concur with Steve that they do not get cold enough. you can sense that the vapor is slightly colder but after using ice with smoking bongs in the past, it's not as cold as i feel it should be. when i've used ice with bongs, back when i smoked more regularly, it was like hitting cold winter air. even on the very first hit, the whiskey stones provide kinda cool vapor. i'm sure the SC glycerin cubes would be able to cool vapor down much more effectively. also, the fact that i'm putting four 'stones' down my glass tube makes me just a little uneasy. no matter how gently i put them in. still a nice gift from my girlfriend though lol.
