hi zsouthboy - here is another method you can use to build a top piece on your popcorn maker.

If you select these 2 curves:



You can then use Construct / Loft to build a surface between them:



Repeat this along the way, doing just a pair of curves at a time, and when you get to the top, select these edges:



And since that area if flat, use Construct / Planar to build a planar surface there to that outline to fill it in:



I'll also try to show you an example of a different way to construct things with thickness rather than this way.

- Michael