Naziv vsebine
DAMMAR handpicked, from Sumatra 500 g
Dammar is a pale, yellowish, easily brittle resin with clean edges. Dammar is found in Southeast Asia; the
name is Malay and means as much as resin or torch (torches made of dammar are very good because they do
not drip). Dammar is obtained from trees belonging to the Diptocarpaceae family.
The most important resin is the one belonging to the Shorea wiesneri, also called Diptodammar. The most common dammar on the market is obtained from Sumatra and may have a prefix according to the place of origin. Padang- or Palembangdammar are the most common types.
Dammar is obtained by cutting deep edges in the trees, in which the resin can accumulate. The resin pieces
on the market are about 3 cm big; however, larger pieces are also common. Dammar pieces, which look like
a pear or club, are obtained naturally, in which it is "sweated-out" by the trees, and not by cutting the trees.
Dammar contains about 40 % resin, dissolvable in alcohol (alpha-resin), and about 22 % resin, nondissolvable
in alcohol (beta-resin). Furthermore it contains about 23 % dammarol acid and 2.5 % water. The slight odor is obtained from the small amount of ethereal oils.
The resin is a little harder than colophony resin, starts to soften at about 90°C and melts at about 180°C.
Dammar is only partially dissolvable in alcohol and ether, and is well dissolved in turpentine oil, chloroform, carbon disulphide and petroleum ether. In a 80 % chloral hydrate solution the resin only swells
without dissolving. The acid value (A.V.) varies between 20 and 30, depending from its origin.
Dammar is indispensible for the preparation of light, clear and easily volatile varnishes. This resin is used as
a final varnish in both oil and tempera painting. In addition, it is also used in oil painting as an additive or
diluting agent which increases the drying time. During the preparation of varnishes or paints, turpentine oil
of high quality should be used (double-rectified). The resin is dissolved cold by stirring often. If stored in
dark bottles, the dammar solution is more stable than under the influence of light. Further dilution should
only be carried out with the same solvent used to dissolve the resin.
Dammar is further applied in the field of photography, to embed slide preparations, in the manufacture of
plasters and plaster casts, and as substitute for Kaurikopal in the production of linoleum.