Metal cleaning and polishing – Easy-to-prepare cleaning / polishing mixtures are made by mixing a fine-grained abrasive with water, to the consistency of thick cream. Alumina is used as a hard metal abrasive, ferric oxide, chromic oxide with the formula Cr203 (not Cr03l), diatomaceous earth. Alumina is mainly used for polishing aluminum alloys. For copper, Silver and their alloys use less hard abrasives: slime chalk, calcium oxide, magnesium oxide, diatomaceous earth, and instead of pure water, it is advisable to use diluted ammonia water (1 volume of concentrated ammonia water + 2 water volume). Ammonia has a dissolving effect on the compounds covering the surface of these metals. Items are cleaned with a soft cloth with a little, often changed, with the amount of the mixture or with a spinning felt disc with the cleaning-polishing mixture applied.
Polishing pastes are prepared by incorporating an abrasive into a mixture of molten paraffin and earth wax (by weight 2:1 or 1:1). The abrasive is selected according to the above guidelines. The addition of abrasive should be 50…60% total weight of paste obtained, that is, on 40 g of wax-paraffin mixture should be added approx. 60 g of abrasive.
The pastes thus obtained have the consistency of a wax.
If a petroleum jelly paste is desired, white oil or kerosene is added to the wax-paraffin mixture, in amounts ensuring the desired consistency, while reducing the amount of paraffin and wax. After polishing, before degreasing, paraffin and wax must be removed from the metal surface, immersing the polished object into benzene for a few minutes, gasoline or trichlorethylene, constantly moving it.