The surface must be clean and free from oil and grease. Proper cleaning occurs with the use of isopropyl alcohol. Dust and stray particles need to be removed. Remains of paint, cement and other particles (such as silicones and sealants, if present in the substrate) must be removed as well.
Some varieties of plastics, paints, coatings or other types of surface treatment have difficulties with adhesion to silicone, so we recommend to carry out preliminary adhesion tests before final application. For most substrates, such as concrete, masonry, ceramics, wood, among others, it is recommended to carry out a pre-test of adhesion before applying unusual materials.
The silicone application must be done at once and continuously. Firmly apply the silicone using the proper tool, ensuring there is full contact with the edges of the area to be applied. Case it is necessary to obtain well-defined and clean joint lines, use masking tape for protection, then, while the silicone is still fresh, remove the tape, doing so will ensure an optimal finish. In order to do the superficial finish of the silicone, use a wet spatula with neutral detergent. The insertion of air bubbles during sealant application should be avoided. The optimal performance of the silicone is directly related to its good application and finishing.
The HARD ALL-PURPOSE SN 525 does not adhere when applied when is applied over other sealant or elastomer and cannot be painted.