Bituminous varnish

Bituminous varnish is a black or dark brown medium viscosity liquid with a characteristic oil odor. Pre-drying time 1.5–2 hours, complete drying - up to 24 hours. Upon drying or excessive thickening, it may be diluted with white spirit or any other volatile hydrocarbon non-polar solvent.

Bituminous varnish can not be mixed with any type of alcohol, oil, turpentine, alkyd and other varnishes and paints.

One of the advantages of bituminous varnish is its low cost.

Coverage

A thin layer of bituminous varnish has a brown color, thick - deep black. The coating formed by varnish is highly hydrophobic , the fresh coating is almost impermeable to moisture, but over time, with the access of air and especially in the light, the coating oxidizes, which impairs its aesthetic and waterproof properties. Bituminous varnish is not resistant to solvents, especially non-polar, very easily soluble in hydrocarbons. The disadvantages of bituminous varnish can also be attributed to the relatively high residual stickiness and even coating marbling, especially at elevated ambient temperatures (from +25 to +30 ° C).

Stains from bituminous varnish on fabric or leather are easily removed with white spirit or gasoline , somewhat worse with turpentine.

The most common bituminous varnish labeled BT-577. There are also paints based on bituminous varnish: BT-177 (with aluminum powder , “silver”) and BT-184 with waste from the production of polyvinyl butyral, which increases the weather resistance.

It is used for temporary waterproofing and aesthetic finishing of metal, wood, brick, concrete. Bituminous varnish well wets the surface, including rust, penetrating even into small pores, which allows, if necessary, to apply it without a primer in several layers with a short intermediate drying time.

Bitumen lacquer: characteristics and composition (Neopr.) . Paint industry .