Mountain sheep Felt has a front and back side. This is because the felt is needled on a polyester “belt” that transports the wool. This makes the front side more open, and the back (under side) more closed in structure. This needling on a polyester belt is also why the felt contains up to 10% polyester; the polyester from the belt slightly enters the felt. The effect of this is that the front side looks more rough and the closed backside looks a bit more shiny. Designfelt can be glued with contact glue (for instance our contact glue). It is also possible to thermoform the felt by shaping it around a base shape and placing it in the microwave. Through the heat the shape will be made permanent which lends itself to a surprising set of new projects, such as hats, slippers and other thermoformed projects!