: Hi Randy,
: Doing multiple layers is doable on large surfaces though it's
: harder to control resin content for least excess weight. Doing
: it in single layers, you can do it as soon as the epoxy of the
: first layer is 'thumbnail markable' but hard. That is usually
: before blush developes so no scrubbing and you get a chemical
: bond. Waiting a day might still get a chem bond but you'll need
: to scrub any amines/blush off first.

: Mike Savage
: South West Cork

Couple of things about two layers of 4 ounce glass vs. one layer of 6 ounce. In most weaves of glass (not all) the yarns the glass is woven from is larger in the heavier glass than it is in the lighter glass so the heavier glass tends to be more abrasion resistant than the doubled lighter glass even though they have a heavier overall weight. There's always a downside, these larger yarns of glass, a more course weave, make it much more difficult to get a smooth finish, so might take an extra fill coat to fill the weave.

Bill H.