DOWSIL™ 732 Multi-Purpose Sealant Enables Long-term Moisture-proof Sealing for Industrial Electrical Control Equipment

An industrial equipment manufacturer specializes in the production of outdoor electrical control boxes and junction boxes. Its products operate outdoors for a long time and are challenged by large temperature differences between day and night, high humidity and salt spray corrosion. Previously, ordinary sealants suffered frequent sealing failure at equipment joints. Moisture ingress caused circuit short circuits and accelerated component aging, leading to a high rework rate. In addition, traditional sealants had poor temperature resistance and were prone to cracking and debonding under continuous high temperature generated by equipment operation.

After multiple rounds of product testing and selection, the enterprise finally adopted DOWSIL™ 732 Multi-Purpose Sealant as the dedicated sealing material for electrical control equipment housings. This is a one-part acetoxy-cure RTV silicone sealant with non-sag paste consistency. It is easy to apply and will not sag or run on vertical and overhead surfaces, which is suitable for various splicing gaps of equipment.

1. Substrate Preparation: Wipe the bonding surfaces of metal housings and plastic covers thoroughly with isopropyl alcohol to remove oil, dust and contaminants, ensuring clean and dry bonding surfaces. For some difficult-to-bond substrates, apply DOWSIL™ 1200 OS Primer as required, and let it dry for 15 to 90 minutes at room temperature.
2. Sealing Operation: Apply a continuous uniform bead of sealant along the housing joints. Finish trimming and shaping within 7 minutes after application (the skin-over time of the product is 7 minutes), and the sealant will become tack-free in about 20 minutes.
3. Curing: Cure the sealant at room temperature with 50% relative humidity. The curing depth can reach 3 mm within 24 hours. Complete the overall assembly and factory inspection after full curing.

After curing, DOWSIL™ 732 forms a tough and flexible rubber layer. The standard version maintains stable performance from -60℃ to +180℃, while the black version works stably from -60℃ to +205℃ and can withstand short-term peak temperature up to 230℃, which fully adapts to the alternating high and low temperature working conditions of electrical equipmentDow Inc.. It features excellent dielectric properties with a dielectric strength of 21.6 kV/mm, effectively ensuring electrical safety.

After 18 months of outdoor operation, routine inspection showed no cracking, debonding or water seepage at housing joints, and no moisture-induced short circuits in internal circuits. The equipment failure rate decreased significantly. The product has excellent adhesion to mainstream substrates such as metals and engineering plastics, eliminating complicated priming procedures and simplifying the production process. Complying with MIL-A-46106 standard, it meets the strict quality requirements of industrial equipment and has become the standard sealing product for mass production of the enterprise’s electrical control equipment.