Marty,
I suggest that you go onto Amazon - books and purchase a copy of David Ellsworth book. First off, it is just a really good book. Second, there is a lot about hollowing, tool making and the like. Along with a good description about how to hollow a vessel. Cost is about $20 on Amazon.

I hollow a lot of vessels and I have made most of my own tools. Way back when....when I first met David at the Davis, CA AAW symposium - he told me he would sell me a set of tools and then proceeded to tell me how to make my own. He explains how in his book. These are hand held hollowing tools.

Next suggestion is to start reasonable small.....maybe 6-7 inches in diameter....and not too tall. The closer to a sphere you make, the easier it is. Start with a reasonable opening and work on making them smaller as time goes on. You need an air compressor to clean out the sawdust. You can do it by hand...but a compressor is much nicer. Stop and clean out the sawdust often.

If you do not want to buy David's book...you local club may have a copy (should have) in the library.

Use green wood - try dry wood later if you want ...but start with green wood.

Hugh