Dark Aluminum / Pyro Aluminum / Dark Powder Aluminum: It is a very fine powder and dark gray in color. Nominal mesh size is 200 but it contains particles of 2µ. There is a wide variety of uses for dark aluminum, for example: flash powders, star compositions, fountains, waterfalls, torches, flares, etc. For all this purposes it is generally used as a fuel.
Many powders sold as “dark” are not really dark aluminum powder but the atomized type (often 63µ) and although the color of the former may vary it has to be dark gray and not light gray or even whitish gray (some of the best dark aluminum comes from Star Molecule and this powder is nearly black in color). Dark aluminum is generally the most expensive of all the aluminum powders.
Atomized Aluminum: It is increasingly used in fireworks although there are only limited uses for it (this is because spherical or spindle shaped particles are more difficult to ignite than a flake). In practice no material coarser than 120 mesh can be used and commercial atomized powders are generally 300+ mesh and light gray to gray in color. It is needed for glitter effects and other special stars, to give an example only.
Flake Aluminum: There are mainly three different types of flake aluminum. The first is “bronze” also known as paint grade aluminum. This fluffy powder is used for making paint and the particle size is very fine (sometimes less than 2µ). Paint aluminum generally contains grease or stearin (the content varies from one to four percent by weight) which decreases its reactivity. This type of aluminum powder is also used in rocket fuel.
Nevertheless aluminum bronze is easily obtained from an artist supply and produces quite good silver effects. It can be used wherever “bright” aluminum is mentioned in a composition. Generally it´s a dirty business to work with fatty aluminum. It only passes the mesh when accompanied by another material. The second flake aluminum is the real “bright” or “brilliant” powder we can substitute with bronze for most purposes.
Bright aluminum usually passes 120 mesh (nominal mesh size 120-200) and like “bronze” is very fluffy and leafing mass. The main difference to the latter is that brilliant powders contain less grease/stearin (0,5% by weight max) or are coated with another material which means that they are not as fatty to handle as bronze grades. They are used as a fuel for many purposes and to obtain silver effects.
The third flake grade is called “flitter” which means flake powders of a larger mesh size than bright aluminum. It is sold as “fine”, “middle” and “coarse” flake/flitter. Some people think that using flitter larger mesh variations are allowed. Sometimes this might be true but corresponding to the correct mesh size often makes the critical difference. As a rule of thumb fine flitter is: 80-120 mesh, middle flitter is: 30-80 mesh and coarse flitter (=coarse flake) is 10-30 mesh.
Referral to the aluminum powder msds sheet for any extended technical data.