Originally Posted by scsmith
Bleeder: polyester quilt batting works pretty well. polyester flannel will work fine, you probably want to use several layers.
Photo illustrates what Steve said about using several layers of flannel. Depending on how wet the layups are, it's possible to squeeze a lot of epoxy into the bleeder ply. The shiny areas are fully saturated bleeder ply flannel. I think this was two layers thick.
For sure you don't want it sucking up into your vacuum pump, so at minimum, stack up multiple layers where the hose will attach.