This is a great project and the 8 inch mirror gives you some wonderful viewing!
He used a concrete form tube and encased it in epoxy resin and fiberglass cloth. The table top mount that he uses is terrific. It makes this telescope easy to pack into the car for driving off to darker skies.
One of the terrific things about this telescope is the mirror mount. It is really neat. Notice how it squeezes the mirror to hold it in place. It doesn't have any clamps that fold over the mirror . This enables the full surface area of the mirror to be used. No part of the mirror is blocked at this stage.
Here is an open view of the assembly.