Dammar gum


Dammar, also called dammar gum, or damar gum, is a resin obtained from the tree family Dipterocarpaceae in India and East Asia, principally those of the genera Shorea or Hopea. Most is produced by tapping trees, however, some is collected in fossilised form on the ground. The gum varies in colour from clear to pale yellow, while the fossilised form is grey-brown. Dammar gum is a triterpenoid resin, containing many triterpenes and their oxidation products. Many of them are low molecular weight compounds, but dammar also contains a polymeric fraction, composed of polycadinene.

Uses

Dammar is used in foods, as a clouding or glazing agent, and in incense, varnish and other products. Dammar varnish, made from dammar gum dissolve in turpentine, was introduced as a picture varnish in 1826; commonly used in oil painting, both during the painting process and after the painting is finished.
Dammar crystals are also dissolved in molten paraffin wax to make batik, to prevent the wax from cracking when it is drawn onto silk or rayon.
Damar crystals are dissolved into beeswax with pigment added to harden it in order to make encaustic paints.
Dammar resins were often used in the past to caulk ships, frequently together with pitch or bitumen.
Damar gum is a common mounting material along with canada balsam for preparing biological samples for light microscopy.
The name dammar is a Malay word meaning ‘resin’ or ‘torch made from resin’.
There are two further types of dammar, besides the gum:

Physical data

The gum is stable, probably combustible and incompatible with strong oxidising agents. Its toxicity is low, but inhalation of dust may cause allergies.