Why does the glass require polishing?
Well-known school examples about the different thicknesses of the top and bottom of the window glass that has served for many decades. Since in the manufacture of sheet glass welded mass is rolled out by special machines, on its surface are formed the smallest irregularities and defects that repeat the profiles of working surfaces and rolls.
To eliminate such technological defects, to make the surface of the sheet smooth and smooth, glass is polished. This is a primary, coarser treatment, as a result of which "large" defects are eliminated( scraped off).This does not end the surface treatment.
The technology of its production, except for grinding, necessarily provides for thin polishing of glass, as the final operation that imparts the required qualities of transparency and brilliance. By the way, some four hundred years ago, the formatted glass in the windows was a sign of a fairly high level of prosperity, and up to now the expression "Venetian mirror" has come to us, as a characteristic of the high quality of the glass surface of a large area.
Such mirrors were large in size, ideally smooth surface and very expensive. Today they can be seen in the Hermitage.
Industrial glass polishing
In industrial production, special conveyor belts and lines are used for grinding and polishing glass, appropriate abrasive tools and compounds( glass polish) are used at each stage of processing. These can be metal disks that perform an initial two-stage grinding and soft polishing devices, with felt or cloth surfaces.
Often a special fine-abrasive paste for polishing glass is used. Technologies can provide treatment with the use of a large amount of water - hydroabrasive techniques. In addition to mechanical processing, chemical methods of polishing are also known in the manufacture. Such polishing can be carried out with a mixture of hydrofluoric and concentrated sulfuric acids.
As a result of the reaction, the joints formed in the top layer make the surfaces smooth and smooth .Thus, in one technological operation, grinding of glass and its polishing is combined.
Polishing glass at home
The need for glass surface treatment often arises to eliminate scratches or minor defects. To talk about the use of chemical methods, apparently, does not make sense. At home, it is better to recall the experience of previous generations in how to polish glass. For this, the mechanical method is the most suitable.
Although small scratches can be masked with the help of various wax-like transparent materials of natural or artificial origin, this is undoubtedly a temporary measure and does not give a qualitative result. Therefore, nothing else, like polishing glass, does not remain. These works can be performed using power tools.
Completely suitable conventional electric drill or surface grinder. Of course, you will need both abrasives and pastes for polishing glass. Depending on the defect, for example, the depth of scratches, appropriate preparation for polishing is required. As already mentioned, polishing is the final and final stage of surface treatment. Therefore, in the beginning, the place of the defect is subjected to careful treatment with abrasives of a larger granularity.
In this case, the granularity of the abrasive powder is reduced at each grinding step( and this is precisely the operation).Of course, the work is not on a dry one. Water or grease is used, and it is better to use special sets of abrasive pastes.
After the scratch is removed, the glass is polished by hand. First, the "thin" paste is applied, at the end the surface is polished only with felt and cloth nozzles. It should be remembered that the execution of local grinding of the site with a scratch removes the microlayer in this area. Therefore, the polished area should be much larger than the grinding area.