We supply decorative components and assemblies to the market place in a variety of finishes. Please see the list at the bottom to see what types of finishes we offer.
Did you want the long story? Here it is:
Zinc melts at a lower temperature than aluminum (Zinc: ~800°F vs. Aluminum: ~1200°F), which means that aluminum is exposed to more extreme temperatures than zinc. When liquid metal is pumped into a casting, the casting (AKA tool or die) has to be cold in order for the metal to cool down and take shape. When liquid aluminum goes into the casting at 1200°, it has to be cooled off very quickly. This is hard on the tool and on the surface of the actual part. The 400° difference between zinc and aluminum makes all the difference in the surface texture of the end part. An aluminum part can still be finished nicely, but often times it takes significantly more post production preparation.
Another contributing factor is the way these metals are pushed into the die. Zinc uses hot chamber casting, which is when the liquid zinc can be pressured directly from the kettle through a gooseneck and into the die. Casting with Aluminum requires cold chamber casting, which is when the liquid aluminum has to be poured into the gooseneck and then pressured into the die. The pouring process involved in cold chamber casting allows for much more gas to be entrapped in the aluminum than during hot chamber. These additional gases contribute to the comparably rough surface of aluminum castings.