For the base I used a box with a small edge to catch the lava when we erupt our volcano. I then sellotaped a small box in the center to give the lava chamber height. I made the lava chamber by cutting a milkshake bottle in half.
We then glued loosely scrunched up newspaper around the frame and then secured it with masking tape.
We mixed some paper mache: 2 cups of flour mixed with 2 cups of water. We then used it to stick strips of newspaper all over the volcano. We covered it in 6 layers. We applied the first three layers on day 1 and left it to dry a little next to a hot radiator for a hour between applying each layer. I then left it to dry properly over night. In the morning it was completely dry and we did the same with the last 3 layers.
After painting it and allowing it to dry we took it outside to make it erupt. We filled 1/4 of the center with baking powder and then added 4oz of vinegar, and a drop of red food dye.
When the lava dried it gave the volcano a awesome effect.