Perhaps the most popular polishing agent can be called GOI paste, since it can be used on a variety of surfaces, ranging from rough metals to glass and soft plastic displays of mobile phones.
The name of the paste is deciphered as follows: State Optical Institute, where they developed this useful product in the 30s of the last century.
GOI paste: appearance and composition
GOI paste is made in the form of sticks from pale to dark green, depending on the content of chromium oxide powder in it (it can vary from 65 to 85 percent), which forms the basis of the paste. In addition to chromium oxide, it also contains organic (fatty) binders and excipients (activating and intensifying additives), such as solvents and chemicals like stearin, kerosene, silica gel (silicon dioxide, white porous mass with absorbing (adsorption) ability) and other
GOI paste is produced both in the form of paste and in the form of soaked felt soft polishing wheels.
What surfaces is GOI paste used for?
Use this tool for polishing and grinding steel alloys (including thermally hardened) non-ferrous metals, glass (including optical), hard polymers and plastics, ceramic materials. GOI paste is applied easily and holds well on polishing wheels.
GOI paste: classification and varieties
Polishing with GOI paste can be carried out using 3 grades of paste: coarse, medium and thin.
Coarse paste in its composition has about 81 parts of chromium oxide, 5 - fat, 10 - stearin, 2 - kerosene and 2 - silica gel. It has a light green tint, it is most effective in terms of the volume of material being removed, giving a matte surface. This type of paste removes small scratches remaining on the surfaces after processing them with various abrasive materials (for example, after grinding).
The average paste consists of 76 parts of chromium oxide, 2 - silica gel, 10 - fat, 10 - stearin, 2 - kerosene; It has a pure green color and makes it possible to achieve a clean surface and even gloss.
Thin paste is made at the rate of 74 parts of chromium oxide, 2 - kerosene, 1.8 - silica gel, 10 - stearin, 0.2 - drinking soda (bicarbonate), it has dark green and black-green shades and is used for finishing (fine lapping), giving a mirror shine.
In addition to this classification, GOI paste is also divided by numbers, depending on the size of the abrasive particles: No. 4 - coarse, to remove scratches and impart a matte surface, No. 3 - medium, for a clean surface without strokes; No. 1 and 2 - thin, for clean polishing, dressing, mirror shine and fine-tuning of various tools for woodcarving.
The most widely used paste is No. 2, as it is perfect for polishing jewelry or other surfaces made of non-ferrous metals, glass, hard polymers and plastics.
GOI paste: application
Few know how to properly use this tool. Next, I give instructions that will help to cope with polishing with GOI paste without any problems.
A small amount of the product is applied to the polishing cloth (soft cloth, flannel is ideal) or to the polishing wheel. Do not apply the paste directly to the surface you are about to polish.
Next, the paste that was applied to the cloth is rubbed on any piece of metal. This is done to remove large pieces of paste that can scratch the surface.
Before applying the product, you can rinse the cloth in kerosene or gasoline for lighters. This will greatly improve the dissolution of this paste.
Then drip a couple of droplets of “spindle” (industrial liquid oil) onto the polished surface and begin polishing the desired surface.
Periodically, you need to drip oil on the product. And when polishing, do not make sudden movements with your hands, do not press the surface too hard, because this can not only not remove existing scratches, but also add new ones. Polish to the desired gloss.
At the end of work, rinse the product well, preferably in kerosene. If not, remove the remaining GOI paste with water.
Here is such an effective and easy to use tool.