At times a skinny pliable plastic film backing on the fabric is applied to support the vacuum perform a lot more effectively. Two factors appeared to be at get the job done. Pigments in paints and stains safeguard towards UV harm, even though UV-absorbers are added to polyurethane and other varnishes (in specific "spar" varnish) to work against UV hurt. Polyurethane components are commonly formulated as paints and varnishes for finishing coats to shield or seal wooden. The two holes in the foam at the leading of the photograph are for the headrest posts. A complete, completely assembled seat protect is placed in the mould and held in area by vacuum drawn by modest holes in the mold. The metallic seat frame is placed into the mildew and the mould shut. At this stage the mildew has what could be visualized as a "hollow seat", a seat fabric held in the right situation by the vacuum and that contains a room with the metallic frame in location.