I need a custom fit tank for my jet..Can I make myself and if so how and with what? Thanks for any help Todd

Do a search in the composites forum of RCU, you will find a lot of information on doing this.

Carve a chunk of foam to the desired shape (actually about 1/16"-1/8" undersized).
Cut it in half in such a way as to provide draft to both halves (so you can get the part off the molds).
Add a balsa back plate to one half that is about 1/16" larger than the outside edge of the foam (this will provide the lip for joining the halves later).
Cover with Econokote (or other low temp iron on covering).
Wax and polish at least 5 times with mold release wax. Spray on a coat of PVA mold release.
Lay up the part with fiberglass or kevlar with epoxy or vinyl ester resin.
Trim excess cloth, and remove parts from mold.
Glue tank fittings (which you can get from BVM) in with Hysol.
Join halves with Hysol.
Fill with fuel and go fly!

Easy!