mastics used for gluing of rolled materials on various surfaces and gluing strips of rolled materials in multi-layer coatings.
used and how obmazochnye materials, as well as protective coatings. There are asphalt and wood tar mastic. Bitumen is used for sticking glassine and roofing, tarry - roofing and roofing skin. Pastes can be hot and cold various brands: hot bitumen roofing - MBK-G-55, G-IBC-65, MBK-G-75, G-MBC and MBC-85-G-100; tarry - MDC-T-50, MDC-T and MDC-60-G-70. The figures indicate the melting point. Prepare mastics from binders (bitumen, tar, sand) and dry fillers: peat crumbs, chalk, fine or asbestos №6 №7, ground slag or limestone, wood flour, sifted through a fine sieve. Fillers reduce brittleness pastes at low temperatures, increase its heat resistance, reduced consumption of bitumen at low temperatures. It is best to apply the fibrous fillers - asbestos and wood flour.
to fire the boiler or the tank, which is preparing mastic recommended immurated brick and strengthen over them heavy tight-fitting lid. Extraneous with molten bitumen remove mesh stretched over a wire or a tin can with holes punched in the bottom and fastened to a long handle. For a quick melting bitumen and pitch is recommended to lay the tank into small pieces.
Preparation of hot bitumen mastic. To prepare 10 kg of mastic requires 8.5 kg of bitumen oil N-70/30 (grade 4) and 1.5-1.7 kg filler. Loaded in a bowl 3/4 of its volume of bitumen is heated to melting. When it begins to foam, to remove surface impurities surfaced. Heat the bitumen is necessary as long as it stops foaming and will not become dehydrated. Bay fire water in bitumen add dry filler and thoroughly mixed. Cooking mastic should be 2-3 hours before the start of the work and apply only in the hot state.
Preparation cold mastic. To prepare 10 kg of mastic is necessary to 5 kg of bitumen BN 90/10 (grade 5), 3 kg of green oil, or exactly the same amount of kerosene and 2 kg of fine filler (better or asbestos №6 №7). Prepare mastic follows. The dish is charged with bitumen melt it until it stops foaming, remove impurities, pour water and fire with constant stirring pour into the bitumen in small portions green oil or kerosene, and then (also in small portions) - filler. The whole was mixed. Cooked paste is poured into a hermetically closed container.
Preparation of wood tar mastic. To prepare 10 kg of mastic needed: 5 kg of coal tar, 3 - coal sand and filler 2 kg. The dish is charged with tar, heat it and add in small portions to coal tar pitch. All this melt and mixed until until no further effervescence. Take off surfaced impurities, extinguish the fire, the filler is added in small portions, carefully all mixing. Wood tar mastic used only in hot form.