Acrylic is a sheet of material that is heated and vacuum formed over a mold, creating a continous waterproof membrane. It is then reinforced with fiberglass. Gelcoat fiberglass is a polyester resin sprayed onto a mold and then reinforced with fine glass particles. One is a solid surface, the other is porous.
Catalysts are renown for longer burn times but tend to be more finicky. The technology results in cooler flue temperatures which can inhibit draft so a proper chimney is critical in achieving good performance. Secondary burns stoves do not burn quite as long as their catalytic cousins but are less dependent on chimney performance due to hotter flue gases. These higher stack temperatures result in superior draft. Both burn very clean when properly installed, however, secondary burn stoves need to burn hotter to achieve the same results, hence a shorter burn.
The following video clip demonstrates secondary technology at work. The stove is a 2cu/ft Hearthstone Shelburne, burning a load of birch, dampered down completely after ensuring a proper bed of coals and charcoaling of the fuel. Stack temperatures are 500F. Note the stove burns from the top down. This kind of burn optimizes fuel, performance and produces the lowest emissions possible. The stove should burn 8-9 hours down to a bed of coals.
