Paul,

I worked at Owens Corning Fiberglas as an engineer in the composites group. I kind of know about this stuff.

G-10 is made of fiberglass cloth laminated with resin. G-10 and fiberglass board are usually used interchangeable and are the same thing.

G-10 is what is commonly used in circuit boards and when you buy raw fiberglass cloth board it's usually referred to G-10. It's more of a brand thing like a lot of people refer to vacuum cleaners as Hoovers.

He says his are made from G-10 (fiberglass). I don't see a problem with that. He's just specifing the material, ,fiberglass, that it is made of.