I am making a Hawaii beach theme cake with a volcano on top and my plan was to make the volcano out of rice krispies and cover with fondant and in the center of the volcano I would put a cup that could hold dry ice so it would look like smoke coming out of it. Any suggestions on the best way to do this or will it not work? If anyone has used dry ice before, how long will the smoke last for?
Thanks
it will definitely work........the bigger your chunk of dry ice is...the longer it will smoke. I'd say out of a chunk the size of a regular ice cube, you'l probably get several minutes of smoking easily. If you can get yourself a nice long/tall glass container (wal-mart has them), like a vase, then you could really fill it up with cubes and get a much longer "smoking" out of it. HTH
Oh and make sure you've got gloves and tongs for handling the dry ice, it'll give you a nasty burn!!!
You could also you a little votive candle holder to put you dry ice in and drop it down in too, I have seen that being used to, hope that helps.
I did a dry ice volcano last Feb.... When the tongs touch the dry ice, it sizzles! really cool, but make sure to use gloves. My volcano was cake, and I used pvc pipeall the way to the base . I sealed the pvc pipe, becuase to activate the dry ice, you need to use a small amount of WARM water. cold water works, but not like the warm water! . I forget just how cold it is, but its something like 200-300 degrees BELOW zero, so even trying to put it in your freeer at home will NOT make it last any longer. You will need to get your dry ice shortly before you need it. Most ice companies around here (upstate ny) dont carry it, so I had to go to a welding company! They guy looked at me funny when I told him what I wanted it for! 
I have pictures if anyone is interested...
I was under the impression that you have to use a metal object to hold the dry ice as it will crack glass and plastic because it gets so cold. Am I wrong on this?
I wouldn't use glass, but pvc worked great!
Thats a good price, I think I paid 3 something a pound... 
Yes, you will need to add quite a bit of dry ice to make it last a long time. Another good tip from dry ice, is to buy the dry ice as close to the time you are using it. It sublimates very quickly and will reduce the amount of time you can use it. But, if you are making a volcano that you need smoke for a while, I would keep adding it to the volcano as it starts to dissipate.
Been using dry ice at Holidays for over 30 years....Do not put it in the freezer. It will do no good. Keep it in an insulated small lunch size cooler wrapped many times in newspaper. If you keep it well insulated it will keep 8 to 10 hours before you use it. Put more newspaper to fill up container around the wrapped dry ice. Leave no room for air. And do not touch it. It will burn you badly. Use gloves
Quote by @%username% on %date%
%body%