Sometimes stains appear on building stones , which are mostly light to dark yellow in color, after a few months to years of installation. These stains reduce the appearance beauty of the building.
On the other hand, white stones, such as Aligudarz and Azna porcelain or Abbas Abad stones, show more yellowness due to their color, so more sensitivity must be used in the implementation of these stones.
There are many reasons that may affect on the yellowing of stones, these reasons include:
1-Yellowing of stones due to epoxy;
2-Yellowing of stones due to 123 glue ;
3-Yellowing of stones due to the presence of metal impurities;
4-Yellowing of stones due to foreign metals;
5-Yellowing of stones due to water salts;
6-Yellowing of stones due to acid rain.
Stone stains caused by accelerators or spray adhesives are depended on two factors: oxidation and sulfation.
Glue yellow stains on stone
Yellow stains are caused by the sulfated adhesive accelerator spray 123 glue on the stone. These stains penetrate deeply into the stone and cannot be removed with thinner and acetone.
Glue green stains on Stone
Green stains are caused by the oxidation of the one two three glue accelerator spray on the stone. Like glue yellow stains, these stains cannot be removed with thinner solvents alone.
Yellowing of Stone Due to Epoxy:
One of the main causes of yellowing of stone is the use of lower quality epoxies during the initial processing of the stone, and also if the epoxy resin or hardener is exposed to oxygen or open air, they oxidize and the epoxy resin turns yellow and changes color. At first, this color becomes opaque and gradually changes to cream and then yellow.
Yellowing of stone due to 123 glue :
Some people use one-two-three glue to install the stone and to perform the work faster. Although this glue sometimes helps to do the work better, if the yellowing is insignificant and the stone is used on the facade or inside the yard, after a while it will fade significantly or completely disappear due to sunlight, but sometimes it will stain the stone and create an inappropriate appearance. As you know, 123 glue has a spray that can accelerate the drying speed of the glue.This spray becomes sulfated after a while and sometimes penetrates into the pores of the stone. Signs of improper use of 123 glue are that you will see green, yellow to brown halos around your stone and at the joints.
It should be noted that:
If the yellowing of the stone is due to the nature of the stone itself, meaning that parts of the stone are yellow when it is extracted from the mine. It cannot be removed.
Using various solvents such as thinner and acetone, etc., not only does not remove the stain, but also causes the stain to deepen on the stone.
