Varnishes, Plaster & Distempers

Varnishes

Varnishes are more or less transparent liquids which are used to provide a protective surface coating in much the same way as paints do” At the same time they allow the original surface to show but add a lustrous and glossy finish to it.

All varnishes have basically the same components as paints.

Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent.

Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss sheens by the addition of "flatting" agents.

Types of varnishes

1. Natural resin varnishes:

Body made from natural resin obtained from certain trees. Natural resin obtained from living trees or from fossils(which are superior) Vehicle in varnish is the same as used in oil-based paint. Resins dissolved in oil ►mixture heated to temperature (500-600OF) depending on the amount of gloss required. Oil and natural resin varnish ►OLEO RESINOUS varnish. Thinner and dryers used in varnish are the same as used in oil based paints

2. Modified natural-resin varnishes:

Made from natural resin ►altered by chemical action. Common resin is heat treated with glycerin to form a gum. This gum is treated as the body for the varnish. Less expensive varnish than the oleo resinous varnish

3. Synthetic resin varnish:

Synthetic varnish produced by plastic industry

Chemicals used include nitrocellulose, amino resins, silicon etc

Vehicle most often the same as for oleo resinous varnish

Coal tar derivatives may be used as thinners

Dryer is also the same as for other types of varnishes