: For the absorbant material I use a couple of layers of paper towels.

: The other point on which I'm unclear now is how much epoxy to leave in the
: glass before laying on the vacuum apparatus. It would make sense to
: squeegee the excess out first, the same as if you weren't going with
: vacuum, it seems, but then what do you really need the absorbant material
: for, then?

: Still, I think the answers are there, and from the little experimentation
: that I've done, it's worth pursuing for the moment. It does leave a
: marvelous smooth surface, with the texture of the taffeta material.

Pete,

The absorbant top layer (bleeder/breather) serves two main functions - to absorb excess resin and to maintain vacuum across the surface. Without the breather part of the function it is possible to have the bag seal off around the vacuum ports and leave the rest of the bag at low pressure (poor vacuum).

Your observations about the clarity of vacuum compacted glass agrees with what I've noticed. I think that the best clarity is attained with a slightly resin rich lay-up from the standpoint of strength to weight. One example of this is the widespread use of surfacing viel on clear finished CF parts. The surfacing viel helps reduce print-through as well as adding a very clear resin rich finish.

Sam