Beautiful effects can be achieved when combing oil paints with encaustic. Oil can give to encaustic greater fluidity, color diffusion, and in some techniques, precision. Encaustic gives to the oil immediate “drying” time, the muted or gloss surface effects of wax, and greater textural variety. But is this combination structurally sound? It can be, but it is important to understand the ways in which a wax paint and an oil paint are and aren’t compatible.
Chemically, oil and wax are “cousins.” If oil is stirred into melted wax, the two will readily combine. In this mixture the balance of oil with wax should be seen as a continuum. At one end of the continuum wax is added to oil to give the paint more body, but the properties and requirements of oil predominate. The paint film will still be flexible, but it will have to go through a drying phase before it sets up and becomes permanent -- in fact, the wax itself will somewhat retard the drying of the oil since it has no drying properties of its own.
At the other end of the continuum oil is added to wax, and the properties and requirements of wax predominate. The oil, however, lowers the wax’s melting temperature and makes it less hard. Artists who make their own encaustic often do so by adding tube oils to melted wax. This dilutes the strength of the pigment, resulting in a more subdued waxy finish. As long as too much oil is not added the paint film will still be hard, and it will set up and become permanent on cooling.There is a danger, archivally, in making a mixture of oil and wax that is too close to the center of this continuum, in other words, where the amount of oil and the amount of wax are equal. At that point the binding and the adhesive properties of both wax and oil are so compromised that the film they form is very unstable, since it is not able to either dry or harden.
Our Pigment Sticks are a very good example of a wax in oil paint. Because they are in stick form, they may seem to have a lot of wax. Actually they have very little wax -- less than 15% of the stick is wax. When molten wax cools, it retains the continuity it had in its liquid state and forms a uniform structure, binding the oil within it. But this wax structure is very weak, and the instant the stick is crushed by drawing it over a surface, the wax structure breaks down and becomes absorbed into the oil. Further manipulation with fingers, knife, or brush turns the consistency into that of a buttery oil paint.
This information was pulled from the resources on the R+F Handmade Paints website.
For more great resources about encaustic:
More Resources on Encaustics from R+F Handmade Paints
Encaustic Workshops at R+F Handmade Paints
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