Vacuum forming wet layups usually use a peel ply and bleeder ply inside the bag incontact with the layup. The peel ply, is usually something like polyester that the epoxy won't stick to that is perforated to allow epoxy through but not the layup. The bleeder ply is the transport to move the excess epoxy thats pushed through the peel ply by the vacuum (yup thats right
![Smile](images/smilies/smile.png)
). Excess epoxy is removed without passing the layup or in this case the aggregate.
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