I'm attempting to make a volcano on a sheet cake....my daughter insists that it erupt.....what's the best way to do that and it not ruin the cake itself?

See if this helps!

http://www.cookingcache.com/dessert/eruptingvolcanocake.shtml?rdid=rc1

Just a thought...would it be possible to use dry ice? Of course you wouldn't get the spewing over effect but you would get the smoke. I was thinking maybe you could make a hole in the top and insert a small container inside with the dry ice and water in the container/ small bottle. Not sure you could get the boiling lava effect without messing the cake up. I would think that dry ice would be food safe as long as it isn't touching the cake but someone else might be able to advise you better. Like I said...just a thought.

Does the volcano "have" to be the cake part that is consumed? You could make a "moat" around the volcano if not for the lava to run into. While the rest of the cake around it is the part that will be eaten.

I don't have a great idea for this but when I saw the post the first thing that came to mind is white chocolate lava colored orange and red...Maybe using dry ice to create the smoke effect and having it fountain out...

I've made the volcano out of fondant covered RKT. I piped the lava down the sides and used a PVC pipe for the center so I could add dry ice. I had the whole volcano on a sheet cake.

I did a dry ice cake for my daughter last year. We used a glass in the middle of the cake. You fill the class 3/4 full with water. Then you add dry ice pellets to create the smoke. It creates a cool effect. I saw it posted on this dry ice website. They have a few different cake ideas. But I did the volcano. It turned out pretty well!

I actually looked into this a while ago because I was planning on making a volcano cake but the party it would have been for then wasn't on... Looking online dry ice in a small container in the centre seemed to be the best way of getting smoke as has been suggested.
At the time I also found an amazing cake which they had mixed in coloured marshmallow fluff with the dry ice and it did erupt and was still edible. I just did a search for dry ice and marshmallow fluff and found a site which looks like the one I might have found back then but I'm at work and the site is blocked so appologies if this link is not appropriate but with luck it might be of use to you:
http://aprilsyummystuff.blogspot.com/2008/03/erupting-volcano-cake.html

If you are in the UK dry ice seems to be only available in commercial quantities which was what my biggest challenge in trying to source all of the parts for the cake. If you are in the UK the only thing I could come up with (I didn't know anyone in a theatre, or other place they use dry ice for smoke effect, well enough to get a small quantity from) was to use a mixture of boiling water, ice cubes (those two to increase the amount of smoke/steam produced between them) and one of the orange effervessent vitamin tables in something like a shot glass in the top of the cake (if you play around with the quantities you should get something fairly satisfactory)

I know how to make it using dry ice, and completely edible...stack 2 bundt cakes on top of each other, carve a small amount around edges of the top piece, to make it look more realistic. Frost with chocolate frosting, and decorate using your imagination...crumbling up oreos to look like rocks, toy dinosaurs/palm trees, raspberry filling or jam around tip to look like lava, whatever you want. Then place a plastic disposable cup, that is large enough to be held at the top of cake by lip of cup. place a few dried ice pieces in cup and slowly pour evaporated milk mixed with red food coloring in it into the cup. It will not "explode", but it will smoke, and bubble over like crazy, oozing all over the cake. The milk only makes the cake moister...does not make it nasty or inedible. I did this for my sons "luau" themed birthday party and ever since I get requests from friends and family to do it for their sons.  He was 15yrs old at the time, and his friends to this day, 7yrs later still talk about how cool that was!

btw, I got the dry ice from our local grocer for free (they get their deliveries with it), some may charge. I would bring a small Styrofoam container to carry and keep in freezer until used...and so you know, it wont last overnight in a normal freezer! have fun trying this, my hubby had as much fun with the kids pouring down the drain and making bubbles and smoke.

And always remember: don't touch dry ice with your bare skin unless you have some reason to give yourself frostbite at the point of contact.

BTW: did anybody notice how old this thread was? I wonder how it went for the OP.