For larger paper sizes, and also when using something other than a plain full-size rectangular deckle, we recommend our ribbed moulds. These fit the same deckles as our plain (non-ribbed) moulds.
These moulds have a second frame which holds a series of ribs against the underside of the mould screen, spaced about 2″ (5cm) apart, to support the screen. This means that the screen will remain tight to the deckle so pulp will not run between the deckle and screen, and also allows more pressure when couching off the sheet as well as helping to keep the top of you post from forming a domed shape.
The second frame is held on with Philips-head screws and the ribs are not stitched to the screening so the ribs and frame can be removed for thorough cleaning of the back of the screen.