In this post we explore the benefits provided by silicone sealants and break down a few of the best products on the market which offer their advantages reliably.
Silicone sealants have been used for many years in the automotive, aerospace, chemical and electrical industries for equipment maintenance and general bonding purposes. They are also used exclusively for certain application which must comply with standards related to contact with food or water, as well as those which must meet strict military specifications. Silicone offers many benefits over other materials when used as a sealant, as listed in the section below.
Main advantages of Silicone Sealants
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Excellent flexibility over large a temperature range (-100°C to 250°C).
Superb weathering resistance due to low chemical reactivity.
High resistance to UV light.
Low flammability due to resistance to oxygen, making it ideal for glazing seals and anti-fire measures.
Ability to form watertight seals as it is hydrophobic.
Great adhesion to a wide range of substrates.
Good dielectric properties, suitable for either electrical insulation or conduction depending on the material’s configuration.
DOWSIL™ Silicone Sealants
DOWSIL™, previously known as Dow Corning, offers the most reliable silicone sealants in the market using their near 70 years of in-depth experience and proven performance. Having more than 25,000 global customers, DOWSIL™ produce silicone sealants that are extremely durable and stable. Additionally, they have the bonus effect of increasing the lifespans of the components that they are used on through their protective properties which prevent moisture, dust or leaks to cause any damage to the components.
Below are listed some of the products offered in the latest DOWSIL™ range of silicone sealants, alongside their features and advantages.
A multi-purpose, one-component, flowable sealant, DOWSIL™ 734 is easy to apply and cures at room temperature within 24 hours. Though able to achieve strong adhesion to many substrates, the 732 is particularly suitable for bonding with other silicone rubbers; which is useful when making repairs on equipment where a silicone encapsulant needs to be replaced. It also offers a fast tack-free time of 13 minutes.
One of the most commonly used DOWSIL™ sealants, the 732 is a general purpose, one-component adhesive which is also easily applied and cures at room temperature within 24 hours. It cures to a tough, flexible rubber though it also offers great adhesion to many different substrates. This sealant is available in black, white, clear and aluminium colours, which makes it suitable for use in multiple applications. It is non-sagging with a paste consistency.
A heat resistant, one-component silicone sealant designed to uphold strong adhesion in applications exposed to temperatures as high as 315°C, DOWSIL™ 736 offers unique features over other sealants. Due to being resistant to high temperatures, it has applications in challenging environments such as aerospace gasketing, industrial oven belts, bag filters on smoke stacks, and many more. It is non-sagging and may be applied overhead or on side walls.
Surface Preparation Tips for DOWSIL™ Sealants
At the very least, ensure that all surfaces have been degreased to start with to remove all contaminants which could hinder adhesion; for which we recommend using a solvent wipe such as Wipemaster Wipe 9. For further effectiveness, roughen rubber surfaces with sandpaper and wipe them again with the solvent wipe before applying the solvent. For optimal bonding, we recommend using DOWSIL™ 1200 OS Primer by brushing, spraying or dipping it on the surfaces that are to be bonded. Once this primer is left to dry for 15-90 minutes at room temperature and a relative humidity of 50% or higher, the DOWSIL™ sealants can be applied for maximum adhesion.
For further information regarding surface preparations, read: What you need to know on bonding plastics.