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  • Checking for Contaminants and Lead Testing

Checking for Contaminants and Lead Testing

Checking for Contaminants

Contaminants sit on the surface of the substrate (or previous paint coating) and can include:

  • Dirt
  • Dust
  • Salt
  • Oil
  • Grease
  • Mould
  • Cleaning residue
  • Surface moisture
All surfaces must be clean and dry before painting. If contaminants are present, the surface must be washed with a suitable cleaning agent to remove the contaminant. It is then necessary to rinse or wipe the surface again to remove any residue left by the cleaning product. 

Expert Tip: Cleaning products such as Sugar Soap are highly alkaline (high pH) and residue left on the surface will affect adhesion of the new coating. Selley's branded Sugar Soap has a pH of 11, and even the best acrylic topcoats shouldn't be applied where the surface pH is greater than 10 (a pH of 11 is ten times more alkaline than pH of 10). Oil-based paints should not be applied to surfaces with a pH level greater than 9. This is also true for cheaper water-based paints containing vinyl resin, as opposed to acrylic resin. The less expensive vinyl resin has a lower resistance to alkalinity.

Cleaning contaminants is one of the most important steps in paint project preparation.

Lead Testing

What is Lead?

Lead is a soft metal element that was used in paints for a very long time as an additive. Lead is highly poisonous. If you are renovating or maintaining a home built before 1969, you’ll need to be extremely careful about the presence of lead paint. Pre-1969, white lead paint was largely used on exterior surfaces, interior doors and architraves. Undercoats and primers frequently contained up to 20% lead. Exposure to lead affects every organ and system in the human body. Lead poisoning can cause brain damage, infertility, immune deficiency and delayed puberty. The use of lead in decorative house paints was banned in Australia in 1969.

How to Test for Lead?

You can conduct your own lead tests using a kit that is available from some of our stores.

We strongly recommend speaking to our expert staff before attempting any project that may involve lead.