Creative reaction for a volcano

[mattL]

I am trying to make a fissure vent volcano instead of the normal mountain. Thought it would be a neat idea to have a container of CaO in a thin plastic container, add water and produce some steam. The heat would hopefully melt the plastic a little and drip into a container to produce the (hopefully more exciting) vinegar/baking soda reaction for magma. I think that the CaOH2 that would form would not produce the gas I would need to foam a soapy vinegar solution, though. Any ideas? Would adding washing or baking soda to the water that combines with CaO make it happen? Better ideas? I've been out of chemistry for a while. So I'm making sure there are no dangerous/pointless steps happening. Thanks!

[hypervalent_iodine]

It won’t produce any gas AFIK, just calcium hydroxide and then calcium acetate. What’s wrong with just using baking soda and vinegar? You could add dry ice if you wanted a nice smokey  effect.