The most popular means for cleaning and polishing jewelry is GOI (green stone) paste. The abbreviation "GOI" means the name of the developer of the tool - it is the State Optical Institute.
What are the types of GOI pasta
There are four types of GOI paste:
1. No. 4 is used for rough cleaning. Removing scratches after grinding with abrasives.
2. No. 3 - for medium cleaning and obtaining an even matte shine.
3. No. 2 and No. 1 - for polishing to a mirror surface.
Composition of the product: chromium oxide, styarin, fat, silica gel, kerosene. The percentage of the constituents determines the number of the type of paste.
GOI paste can be of various consistencies: liquid, pasty and solid, reminiscent of a brittle stone (hence the name "green stone"). Also GOI paste comes in the form of felt, impregnated polishing wheels. But, as a rule, it is a bar of turquoise-green color based on chromium oxide.
The color of the paste can be of different shades, depending on the constituent components: binders, auxiliary substances, various activating additives and the percentage of chromium oxide. The coarse variety is light green in color. The middle variety is slightly darker. Thin pastes are dark green or black with a green sheen.
On sale there are usually either thin or medium grades of GOI pasta. Therefore, you can hear many complaints that lapping with paste does not work. This is because the order of application of the varieties is not followed. And not every seller can explain what kind of pasta he has on sale. It happens that after grinding with an abrasive, you immediately want to get a mirror shine. But you can see a positive result only after lengthy lapping and adherence to the sequence of using the varieties. Starting, naturally, from # 4. For convenience, the paste can be diluted with kerosene or a similar solvent.
When fine-tuning, the devices on which the paste is applied are of no small importance. These can be wooden blocks wrapped in a pile cloth, curly, specially prepared tools for accessing recesses, holes and hard-to-reach places of the objects being processed. In no case should GOI paste be applied to the object to be polished; if this happens after a long process of fine-tuning, it will be unforgivable to start all over again.
It should be noted that chromium oxide, which is part of the GOI paste, is toxic. Contact with skin can cause dermatitis. And if it gets into the stomach, it can cause poisoning. Also, toxic impurities are often included in the paste.
After polishing, you need to wipe the treated object with vegetable oil, and then with a dry cloth. Then the product should be washed with water and detergent or liquid soap.