Mirrors on the market usually come in three different back coatings: mercury, sterling silver and copper. Common mirror sizing after a period of time, the mirror appears speckled, this situation should be the user used acid glass glue, and acid glass glue usually reacts with the above material, causing the mirror to see speckled. Therefore, we emphasize that neutral adhesive should be selected, and neutral adhesive is divided into alcohol and ketoxime type two. If the copper mirror uses ketoxime-type neutral adhesive, the ketoxime will have slight corrosion on the copper material. After construction for a period of time, the mirror can see the traces of corrosion at the sizing place behind the mirror. If the alcohol neutral adhesive is used, this phenomenon will not occur. The above is due to the diversity of the substrate caused by improper material selection. Therefore, it is recommended that users do a compatibility test before using the glue to see whether the glue is soluble with the material. Select appropriate glass glue products to avoid unnecessary losses.