Limitations Of Silicone Sealant

All types of silicone sealants are subject to the following limitations: 1. They are unsuitable for application in areas subject to prolonged water immersion; 2. They are incompatible with materials that exude oils, plasticizers, or solvents; 3. They cannot bond to frosted or damp surfaces; 4. They cannot cure in completely enclosed spaces (as curing requires atmospheric moisture); 5. They are ineffective on unclean or structurally unsound substrate surfaces.

Acid-cure silicone sealants are subject to additional limitations:
Acid-cure silicone sealants can corrode or fail to bond with copper, brass (and other copper-containing alloys), magnesium, zinc, and plated metals (and other zinc-containing alloys). Their use is not recommended on masonry materials or iron-based substrates. Furthermore, using this product on materials such as methyl methacrylate (Plexiglas), polycarbonate, polypropylene, polyethylene, and Teflon (PTFE) will not yield satisfactory adhesion or compatibility. Acid-cure sealants are unsuitable for joints where movement exceeds 25% of the joint width, and standard acid-cure sealants should generally not be used for structural glazing (with the exception of specialized acid-cure structural sealants). Additionally, they should not be used in areas subject to abrasion or where significant adverse effects might occur. Application is not recommended when the substrate surface temperature exceeds 40°C.