This is a general guide on the purpose of each type of abrasive grain currently available.
Aluminium Oxide Sanding Belts Available in cloth and paper. Generally the lowest cost abrasive, aluminium oxide abrasive belts are recommended as a rule for working primarily on aluminium. They are also generally popular in a flexible material for sanding curves/contours and polishing applications (common sizes include 50x1525mm, 100x2740mm and 100x3450mm), particularly in the P120 – P400 grit range for finishing after the stock removal stage before moving onto polishing, e.g. with trizact or felt.
Other options are with a heavy cloth backing, for more aggressive stock removal applications on hard woods/metals, or with an open-coat for working on materials that clog easily (e.g. soft woods, aluminium.)
Zirconia Sanding Belts Available mostly in cloth. Zirconia abrasive belts are advised for use on both stainless steel (with a topsize), and mild/carbon steel (without topsize.) A topsize is an additional layer which keeps the workpiece cool as it grinds so is ideal for stainless steel, and other metals that are prone to burning/discoloration.
Zirconia is sharper and more durable than aluminium oxide, and works best at high pressures, as this breaks down the grain and ensures optimal performance. If used at low/medium pressures then the belt will just start to glaze over, dulling the grain and rendering it ineffective. The grit range is P120 and coarser, as above this there would just not be the pressure to get the best out of a zirconia sanding belt.
Ceramic Sanding Belts Available in cloth only. Ceramic sanding belts are recommended for working on stainless steel, or aluminium where the topsize can help to reduce clogging. This is most popular in a heavy X-weight cloth/polyester backing, but also available in J-flex, for finishing curves/contours and polishing applications.
Offering a faster cut and more durability than both zirconia and aluminium oxide, the optimal performance of ceramic abrasive belts is at low to medium pressures, so these should not glaze over in most conditions. As such ceramic is generally regarded as the most cost effective of the conventional grains, even if it does have a higher price point initially. The applicable grit range is P120 and coarser, as above this it is more cost effective to use aluminium oxide.
Silicon Carbide Sanding Belts Available in cloth primarily, silicon carbide sanding belts are most suitable for stone, glass and brass. The grain is very friable, which means that it is very sharp but also breaks down very quickly, so will not last as long as other materials. It cuts very quickly, giving a bright finish and fine scratch pattern.
The applicable grit range of silicon carbide abrasive belts is P60 – P400, followed by P600 – P1000 with a cork impregnation for finer finishing, and also in pure cork for a very high level or “mirror” finish.
Surface Conditioning Belts The recommended substrates for surface conditioning, or “scotch-brite” belts, are all metals essentially. These offer reduced clogging on soft metals in particular, and are popular for achieving a grained or satin finish and putting a scratch pattern on the workpiece.
Due to their uniform, non-woven nylon web structure, surface conditioning belts give a consistent smear-free finish, and are available in 3 grades mainly – coarse, medium and very fine.
Agglomerate Sanding Belts (Compact Grain) Also known as compact grain, agglomerate abrasive belts are suitable for use on all metals. The abrasive grains are combined to form larger, more uniform granules and in turn a much more even and consistent finish throughout the life of the belt (as opposed to conventional abrasives where the quality of the finish diminishes as the belt wears.)
These are much more durable and longer lasting than aluminium oxide, and popular for achieving a grained or satin finish and putting a scratch pattern on a workpiece. The available grits include P120 – P400, in either J-flex for curves/contours, or X-weight backing.
Trizact Sanding Belts 3M Trizact is suited to all metals, and gives a sharper and more consistent cut than conventional non-woven materials, as well as a much more uniform finish even at medium pressures. Trizact belts can last up to five times longer than conventional belts, offering precise finishing control to ensure fewer stages are needed, as well as ergonomic benefits – there is no need to apply high pressure as the Trizact material maintains its sharpness throughout its life. Available in equivalent grades from A160 (P120 approx.) to A6 (P2000 approx.)
Felt Polishing Belts Recommended for use on all metals and glass, felt belts are ideal for polishing – the final stage, for very fine finishing. These are popular after or in conjunction with trizact belts.
They must be used with polishing compounds, similarly to a polishing mop.