I recently painted over a few old oil paintings. To my dismay, after a couple of weeks of drying, I found that I could easily scratch off the new dried paint with my fingernail. It’s been 6 months now, and the paint still scratches right off.
Paint adherance has never happened when I paint on a new canvas. The only thing I did differently was that I painted on top of older already-painted surfaces.
The surface was too smooth. Through research and testing, I found that the old paint had no tooth for the new paint to adhere. I hadn’t sanded the surface before adding the new paint. My fault. I’ll never do that again. But there’s more to the story.
Smooth Artist Panels
A few weeks later, I pulled out a couple of Ampersand artist panels that I’d had sitting in my studio; I’d never tried them. I noticed their smoothness – no tooth at all. Aha! I figured the same adherance issues would happen with these, too. But the manufacturer’s package said, ‘for oil and acrylics’ and ‘ready to use’ … So I put it to the test. I painted two lovely oil paintings on them. After drying I used the fingernail test again. I almost cried. A long line of dried paint scraped right off, all the way down to the smooth surface. I wasn’t surprised. Oil indeed paint needs something to hold onto.
I contacted Ampersand, the panel manufacturer, and asked them why they say it’s ‘ready to use’. They said it is ready for acrylics, but oils ‘sometimes’ need some prep work, like sanding. They said there’s no “texture to grab the color as there is with a woven substrate, such as canvas.” Well yea. They suggested sanding and oiling out would work.
Exactly. Then why didn’t they say that instead of ‘ready to use’? If this happened to me, it must have happened to scores of other artists.
My take-away? Don’t trust manufacturers’ instructions. And don’t paint on slick surfaces.
Time to sand and repaint all those ruined lovely paintings.