A Guide to Preparing MDF Boards for Oil Painting

MDF (Medium Density Fiber Board) board is made at high temperatures and pressure by combining wood fibres, wax and resin. This low-cost engineered wood panel consists of fine fibers. Also, the MDF board does not have any wood grains or knots. Hence, it gives a smooth and suave surface for painting. The texture of the MDF board makes it suitable for oil painting.

MDF is porous and as such, it soaks up moisture naturally. So, before painting, it should be properly prepared to create a uniform substrate. Hence, the MDF boards should be primed before painting. The primers can control the texture, absorbency, and colour of the surface.

Oil Paint Brush

Preparing the MDF Boards

The quality of the MDF board varies, and as such, you must apply best practices to smooth the edges and ends.

  • By using 150-grit sandpaper, a smooth effect can be achieved. After that, a light coat of filler or joint compound can be applied. It will seal the open pores and give a smooth and consistent finish for painting. The MDF ends should be sealed as moisture results in swelling up.
  • During the production of MDF, the front and back are pressed and sanded. But it should be primed with a primer like Kilz, Bin 123 Primer, or other general finishes. The white undercoat or General Finishes Stain Blocker ensures a better effect. After that, two coats of paint are followed. MDF is less absorbent than natural wood. So, there should be a waiting period of 2 days between coats of paint or primer.
  • MDF generally tends to cast a brown colour. So, a light coat of grey paint should be used instead of primer. Only after that, white coats can be applied. It takes a minimum of 2 days before applying the next coat.

Instead of using a sanding sealer on MDF, you can also use White Undercoat or Stain Blocker for better effects.

Application of Acrylic Gesso Method

Preparing the MDF board depends on the type of finishing you want. In the following way, it must be prepared for oil painting-

  • Use a brush or a roller for applying two to three coats of acrylic gesso. For a smooth finish, sandpaper finishing of gesso is needed.
  • If anyone wants brush marks, use a stiff decorator’s brush. For smaller boards, use a 1” brush to brush in different directions.
  • The final coat finishing depends on the effect needed.
  • To give a white finish, use just gesso.
  • In the market, a limited variety of coloured gesso is available. So, for coloured ground, a mixture of acrylic paint and gesso should be made.
  • A texture paste should be used for a rougher finish. A looser feel to painting can only be attained by applying broken brushwork to the textured ground. Among the various texture pastes, a fine sand texture can be availed by using a white acrylic gesso in the coarse texture.
  • To give a tinted ground, mix the acrylic colour in a clear acrylic gesso coarse texture.
  • Also, you can use a mixture of Polyfilla powder and gesso in a 1:3 proportion. Apply it with a stiff 1” decorator’s brush. It will leave the effect of visible brush marks.
  • It is entirely up to you how short (absorbent) your ground should be. According to that, apply the second layer of texture coat and a final gesso coat on top.

Short Grounds

Short is the very basic layer of paint applied to an artwork.

  • The short ground is more absorbent and more absorbing of oil from the paint, causing the paint to dry more quickly.
  • This is ideal for Plein air or alla prima painting techniques.
  • If a particular short ground is required, then add a little chalk (whiting) to the gesso.
  • Without a ground, the premature dryness of the painting gives a dull appearance.
  • Hence, long grounds must be used to add a glossier look to the painting.

Coloured Grounds

Coloured grounds are the top layers on the short.

  • The coloured ground removes the glaring whiteness of the MDF board.
  • The glazing technique is traditionally used to create maximum luminosity. White grounds make the dark look darker.
  • Different coloured grounds can be used for different effects and to set the mood.
  • Both warm and cool colours can be used to set the mood of the grounds.
  • One rule is using warm ground with predominantly cool shades, and another is cool ground with predominantly warm shades.

So, it is a personal choice on which the coloured grounds to be select...

Wrapping Up

Here, the step-by-step procedure is described to prepare the MDF board for oil painting. Oil painting on MDF boards is quite easy. But you should apply proper techniques and procedures to prepare the surface of the board. Go to the local builder’s merchant and cut the boards according to your required sizes. After that, prepare the surfaces of the MDF boards in accordance with the above rules. Always follow the procedures to attain the best effects for oil paintings.