#PaintersParramatta – Workplace Health and Safety – Hazardous substances Part 3
Aug 25, 2014 Author Sydney Painters; bloomin
Substrate identification can be broken down into two main categories:
Previously painted substrates
Unpainted substrates will generally cause the most problems for the novice painter, and must be accurately identified and prepared correctly prior to applying undercoats or finishing coats.
Some of the more commonly encountered painted substrates include acrylic and enamel finish. “Acrylic” (water based) paint is identified by using methylated spirits to wash off contaminates, as follows:
(i) Use clean water to expose a clean dry substrate.
(ii) Use a clean rag tip soaked in methylated spirits, rubbing the surface vigorously.
(iii) If this process results in the paint being removed and forming a tacky area, one could confidently suggest it.to be an acrylic (water based) finish. If no paint is removed and it does not become “tacky”, this would suggest that it is not a water based finish.
Painting Services – Unpainted substrates
By definition, these have never been painted, and are found in numerous types of construction materials, e.g:
- Off-form and Tilt-up panels.
- Poured, troweled, concrete, e.g. paths.
- Exposed aggregate
- Applied finishes, renders, coloured concrete.
- Concrete blocks
- Clay bricks and pavers
- Natural Stone
- Hardwood or Softwood
- Natural or Treated, i.e. C.C.A.
- Composite products
- Ferrous (Iron and Steel)
- Non-ferrous (Aluminium, Cooper, Brass)
Once these substrates have been correctly identified,’ then appropriate surface preparation and product selection· can be achieved.
Prior to painting, all surfaces must be clean, dry and free from contaminates. In many cases a basic water and detergent wash is adequate, using a clean brush, or clean rags, with clean water and detergent, e.g. a Sugar Soap solution, washing down and rinsing off to remove all contaminates prior to painting.
When previously painted surfaces are peeling or perished, these old coatings need to be removed in order to present a stable and sound substrate, which is suitable for painting. This is generally achieved by manual and by mechanical sanding, using the appropriate grade of sandpaper to avoid substrate damage.
There is a range of sanding machines suitable for all substrates-
• Disc Sanders for rough sawn hardwood.
• Orbital Sanders for dressed timber and softwood.
Note: Angle Grinders are’ not recommended for machine sanding as the sanding discs are not rated to the speed of a grinder, making them unsafe.
When using chemicals or power tools in surface preparation, all safety procedures must be observed and all personal protective equipment should be used.
Painters Central Coast, Residential Painting services Parramatta
For more information about any Painting and Decorating tasks please Call Bloomin’Good Sydney Painters on 1800 204 145.