The purpose of this research was to study the effect of alternative fillers use such as palm shell charcoal and coal briquette ash to the vulcanization characteristics of rubber compound and physical properties of vulcanized rubber. This research was carried out in three stages, namely 1) the manufacture of dry blanket as raw rubber material for the solid compound, 2) preparation of alternative fillers, and 3) the making of rubber compound. The use of palm shell charcoal and briquette coal ash was mixed with carbon black fillers each around 20 phr in the compound making. Parameters observed such as technical quality, vulcanization characteristics and physical properties of vulcanized. The research results generally showed the alternative fillers palm shell charcoal (compound B) able to produce rubber vulcanized with better physical properties than coal briquette ash (compound A). Compound B in combination with of 20 phr palm shell charcoal and 20 phr carbon black produced vulcanized rubber with tensile strength approximately 134 kg/cm2, elongation at break 710%, specific gravity 1.134 g/cm3 and and tear resistance around 429 mm2/kg. Vulcanized rubber of compound A has hardness values (47 Shore A) and tear resistance (21.1 KN/m) which was larger and the optimum vulcanization time faster than palm shell charcoal
