Are Silicone’s Always the Best Choice?

Not a day goes by when our technical department receive a call from a customer looking for ‘silicone sealant’, but are silicones always the best choice?

Silicones tend to be suggested as the ‘all purpose sealant’, however, they are not the first choice for a whole host of applications. Like all families of sealants, silicones offer both advantages and disadvantages. The customer should be aware of both!!

Advantages of silicones:

  • Excellent resistance to UV light.
  • Good tear resistance with medium & low modulus types.
  • Very low shrinkage.

Although silicone sealants are very versatile in their applications, they do have some inherent properties which may limit their use in some applications.

Disadvantages of silicones:

  • Poor tear resistance with high modulus types.
  • Skin quickly which can be an issue in tooling.
  • Bad odour with some types.
  • Cannot be used where physical abuse or abrasion is expected to be encountered.
  • Cannot be used on galvanized metal.
  • Cannot be used in applications with prolonged water immersion.
  • May be problematic when used with building materials which might bleed oils or solvents.
  • May be problematic when used in confined spaces (silicone requires atmospheric moisture in order to fully & properly cure).
  • Should never be used in the manufacture of insulated glass units unless specified.

The quality of silicone can vary greatly. For years, the field has been wide open and specifiers and users are cautioned to be aware of the possible variations in price against quality. The best advice should accompany the best product. Contact our Technical Service Chemist for immediate advice.