Making a cone/ vase for my vase (the inside)

Hi.
There are two approaches
1. Remove this geometry you created and make the mesh double-sided
2. Use Solidify modifier to add the other side
Heres an example: i created a curve, used Screw modifier to make it look like a vase, then added thickness with Solidify. Now I can apply both, starting from the first, then select and remove areas inside the vase that are not visible


Also, for your information, you do not have to use Blender 2.7. If you prefer this interface, use 2.79 instead. If you'd rather work on the newest one, get 3.6. Bear in mind that you need s4s beta for it, not the community tested version