Iron objects are usually only painted. Varnishing helps to protect iron from rusting, and wood from termite and insect attacks. In addition to this, Varnishing also helps to make your home look more ‘polished’. Iron oxide, zinc oxide and titanium oxide are used for varnishing iron, while gypsum, choke and china clay are used for increasing the thickness of the paint.
Mixing together these compounds in liquid form creates turpentine, linseed oil, etc. Also, adding litharge, red lead, zinc sulphate or manganese oxalate will increase the life of a paint job. Turpentine is used as a thinner to ensure that the paint does not stick too much to the brush. The proportion of paint and additives are decided, based upon the type of material to be painted on.
Varnish enhances the appearance and increases the life span of wood. Varnish is transparent, so it retains the natural color of wood. Painted wood can be varnished too. There are different types of varnishes including oil varnish, turpentine varnish, spirit varnish and French varnish. Select the varnish based on the type of wood.