Preparing Masonite hardboard for oil painting

I have been planning to go plein air painting this summer around my neighbourhood, and after thinking this through, I concluded that Masonite was the most suitable support for my plein air painting needs – I have also built a dry box to carry wet panels but that will be the topic of another article.

Low cost, availability of the material as well as its durability are some of the advantages for using Masonite or hardboard for oil painting support instead of canvas. Old Master’s paintings that best survived over the time were painted on wood panels. On the downside wood or Masonite panels, especially the larger panels, can get quite heavy after priming (weight being a factor to take in consideration when you want to frame and hang a painting) and difficult to carry around.

One side of the Masonite board is smooth while the other has a rough, weave like texture to it.

By the way, Masonite is the trademark brand name of a type of board made from wood fibres and resin; one side of the board is smooth while the other has a rough, weave like texture to it. Either side can be painted on, offering a different kind of surface depending on your personal preferences – Make sure to use hard pressed Masonite (above photo) – Avoid the other type of Masonite which looks, and isn’t very different than strong cardboard – It is too absorbent – its loose fibres will absorb the humidity, get unglued and the support will fall apart.

My 11 x 14 Masonite and wood panels

For my Plein air painting projects, I chose to use small 11 x 14 Masonite boards and I don’t plan to carry more than 2 paintings per session, so weight will not be an issue. I’ll also use wood panels that used to serve for cover of wine boxes (one side had angels and grapes designed on them, so I’ll prime and paint on the other side)

Sanding the Masonite board surface for more adherence and remove impurities.

I decided to use the smooth side of the Masonite panel, so before priming I’m sanding its surface. This serves two purposes: It adds adherence for the gesso I’ll be adding later, and sanding removes some impurities like oil residue or in this instance, the remaining glue from the price tag and which has left a dark stain on the Masonite – If not ridden of, such impurities can leak through the gesso and leave stains on the artwork.

The first coat of gesso gets absorbed making the suface look patchy.

Then I’m ready to apply gesso – here I have used an acrylic based gesso – with a large hog bristle brush. The first coat gets absorbed more and it kind of looks patchy (see above photo), that’s okay, I’ll add another coat of gesso on top and count it as if it was my first coat – In total, I have added 4 coats of gesso, sanding in between each, but before I started the sanding, I noticed that the first coat of gesso made the Masonite panel wrap a little. To remedies this problem, apply gesso to the other side (boards larger than 18 / 20 inches should be reinforced with stretcher bars to prevent wrapping)

A coat of black gesso on the other side of the masonite board to prevent it from wrapping.

I happened to have some black gesso around, which is what I used on the other “rough” side of my Masonite boards – that is kind of sharp looking I think – but some plain white, regular gesso will do just as well. I applied the gesso generously, to make sure to fill all the little holes in the texture.

A rough 120 sand paper to sand in between each coat of gesso.

I used a rough 120 sand paper to sand in between each coat of gesso – Very important to remove all the sanding dust before adding another coat of gesso. Wipe-off with a dry cloth and then remove remaining with a slightly wet cloth – On the last (4th) coat, I used a 280 and then even finer 320 sand paper to get a smooth surface. I have made sure to gesso and sand the sides as well to get a perfect seal.

Finished Masonite panel – I have made sure to gesso and sand the sides to get a perfect seal.

At last, I applied a ground colour to some of my masonite panels. I like using ground colour for it reduces the white gesso’s glare, which can make colours and values difficult to gauge. Ground colours can also be used to enliven or neutralize certain colours when applied transparently or in broken colour. I have read that red is commonly used as ground colour for plein air painting – apparently it helps the enliven greens and that sky blues can benefit from a reddish/violet hue – but given that I couldn’t find other information to back it up and that I have some doubts about red, which I find to be too intense, I decided to experiment with different ground colours.

Experimenting with different ground colours.

Here I have tried one using pure straight off the tube Cerulean blue, Carmin red, and a mixture of the two. Using one part paint, one part linseed oil and one part mineral spirit for the ground colour applied roughly with a large hog bristle, and wiping off the excess with a cloth.

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