Q. Two years ago I set aside an unfinished painting of water-soluble oil on canvas that I’d like to start working on again, but I’m concerned about possible adhesion problems between the new and old paint layers. Are there any special precautions I should take before adding more paint?
A. First, as a minor correction in terminology, I’d like to mention that the paints you’re asking about are really considered water-miscible rather than water-soluble. Water-miscible, or water-mixable, means that you can clean up or dilute the paint with water, but I don’t want artists to be misled into thinking that once the paint is dry it will be water-soluble. The dried paint film won’t be dissolved in water.
The manufacturers of water-miscible oil paints claim that they dry and age just like regular oil paints do. Unfortunately we can’t be sure about the truth of this claim because of a lack of reliable testing on this type of paint, but if the claim is true then you should be able to add paint to your 2-year-old painting without any problem. In general, however, here are a few tips on assuring good adhesion in any oil painting when you need to resume work on it after the paint has fully dried.
Before resuming work, wipe the surface of the painting thoroughly with a cloth dampened with mineral spirits, and feel free to use the odor-free kind if you’re bothered by the odor. Then allow the mineral spirits to completely dry, and just before beginning to paint apply a thin coat of what-ever fast-drying painting medium is recommended for use with the brand of paint you’ve chosen. (The manufacturers of water-miscible oils all make painting mediums to use with their paints. For a regular oil painting or an alkyd painting, use an alkyd painting medium.) Finally, wipe off any excess and then paint directly into the wet painting medium. This way, you’ll be assured of a good bond between the old and new paint.
Betsy Dillard Stroud lives in Scottsdale, Arizona. North Light Books will publish her Painting From the Inside Out: Projects to Free the Creative Spirit in April 2002.