Universal undercoat buying guide

An undercoat is generally made up of a binder, resin and pigments. A universal undercoat differs to standard undercoats in that it contains a much higher percentage of adherent resins allowing it to adhere to a wide range of surfaces.

While a universal undercoat will stick to almost any surface, it will do a fairly limited job on trickier surfaces such as PVC, glass, laminate and metals. These surfaces should be tackled with a surface-specific primer for optimal adherence.

Universal undercoats come with a wide range of advantages – mainly that you can use one product for a range of tasks. However, there are a few drawbacks to using this type of undercoat.

Advantages

• Adheres to almost any surface.

• Painting tools can be cleaned with water.

• Can be used on most absorbent surfaces.

• Will render surfaces non-absorbent.

• Gives smooth surfaces better adherence.

• Evens out surfaces.

• Offers better coverage.

• Avoids buying several products.

Disadvantages

• Poor adherence on some surfaces such as glass or very smooth surfaces.

• Will seep into very porous surfaces.

The process of applying a universal undercoat is basically the same as any painting job.

Prepare and clean your surface 

Preparing your surface guarantees a neater finish. To so do, you will have to fill in any holes and cracks using filler or putty depending on the surface you're working with. After filling, you will need to sand the surface to achieve a smooth finish.

Dust down, clean and degrease the surface to ensure it is as clean as possible. Your choice of degreasing agent will depend on surface type: pine resin, white vinegar, rubbing alcohol and acetone are all good options.

Prepare your equipment

Kit yourself out with the following painting tools:

• edging brush for corners and edges;

• roller, masking tape, paint tray and grid;

• safety wear including a mask, gloves, safety goggles and overalls.

Apply your undercoat 

Just like when you apply ordinary paint, start by tackling the corners and any spots that are trickier to reach with an edging brush or small roller. You can then use a roller to cover the whole surface. Don't worry too much about the finish as the undercoat is only really intended to increase adherence – the topcoat will take care of the rest!