POWDER GRINDING.
The most commonly used powder is silicon carbide sanding (SIC) Zwany Karborundem. This material is obtained by artificially, having a color from greenish to black, which comes from pollution (pure is colorless).Its hardness on the Mohs scale is about. 9,2 do 9,5 ( for comparison, the hardness of talc = 1, hardness of diamond = 10).Another abrasive powder available to amateurs for the processing of the glass is elektrorund, or equivalent synthetic corundum. Al2O3 is chemically, its hardness is less than the carborundum and the Mohs scale is ~ 9 . Elektrorund is white ( it really is transparent).Due to the lower hardness of many amateurs use it performs very end of the grinding.
Abrasive powders are sorted by the producer and the grain size fractions are numbered, usually thicker proszkom are assigned lower numbers. For example, under present some grit abrasive powder and numbers assigned to it.
No. 80 - 200-160 μm
No. 150 - 100-80 μm
No. 24th-63-50 μm
No. 320 40-28 μm
No. 500 20-14 μm
No. 800 10-7 μm
Polishing Powders.
For polishing optics are most often used cerium oxide and iron oxide. Cerium oxide is usually in various shades of beige. Iron oxide is a brown color. Faster cerium oxide polished, while many astroamatorów iron oxide is used for final polishing step, because of its slower action allows more control over the final stages figuryzacji. In fact,use of the polishing powder depends on the individual preferences of the person polishing (I usually start and finish polishing with cerium oxide).
How to handle powders.
Always avoid confusion and confusion powders. Each gradation grinding powder should be stored in a separate, well-sealed container in which to save the number of gradation. Additionally, coarse powders should hold on another shelf or in a different drawer than fine powders, Polishing powders and away from the grinding if conditions allow. If we have a cabinet with some shelves, This on top, keep polishing powders, fine powders under grinding, while the lowest grinding coarse powders. polishing in terms of amateur, coarse powders can be applied to “drought” and then add water using a hand sprayer such as potted plants. Finer powders best applied with a brush after mixing with water. At the same time for each powder should have a separate brush. It's no illusion, hoping to wash the thick brush and apply powder to a fine not suffer the consequences in the form of scratches on the mirror.
Polishing powders are also the easiest brush applied as an aqueous suspension. There probably is not necessary to mention, that the brush must be designed exclusively for poleru!