up to about 4 inches or longer in length can be used in a wet process for making fiber glass mats and even longer fibers can be used in some dry processes like needling lapping or stitch bonding while the majority of the fibers used in the present invention are glass fibers a minor portion of non glass fibers can also be used such as cellulosic fibers including wood pulp of all kinds cotton linters cellulose derivatives such as cellulose triacetate rayon etc man made organic fibers such as nylon u2122 polyester polyethylene polypropylene etc can also be used instead of cellulose fibers in any various blends with one or more cellulosic fibers the fibers in the mats are bonded together as described earlier processes for making nonwoven fiber glass mats are well known and some of them are described in u s pat nos 4 112 174 4 681 802 and 4 810 576 which references are hereby incorporated into this disclosure by reference but any known method of making nonwoven mats can be used the preferred technique for the making of mats of the present invention is forming a dilute aqueous slurry of fibers and depositing the slurry onto an inclined moving screen forming wire to dewater the slurry and form a wet nonwoven fibrous mat on machines like a.