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Painting oil over acrylic work


(Curtis H) #1

I have an acrylic painting that I’d like to paint over in Oil. Literally, over the acrylic.

From my surfing, this is possible with a matte medium covering the whole acrylic work after thoroughly drying.
This would allow me to see the old work as I paint with oil over it.

Are there any quick tips to increase archival strength that what Ive described.

  1. I want to see the old artwork to reference
  2. Have to have the bare minimal tooth from a matte medium for the oil to adhere to.

Any tips or alternative solutions very welcome!

Thanks!


(Curtis H) #2

I found my answer from Golden’s Just Paint blog:

http://www.justpaint.org/using-oils-with-acrylics/


(Dave Gehman) #3

That article has a lot of good insights into your problem, but seems to somewhat de-emphasize the main issue, adhesion.

If your old acrylic surfaces are shiny, you need to adopt some old house painting techniques. Back in the bad old days of oil-based house paints, each round of taste in interior decorating went back and forth - there would be a period where you wanted shiny surfaces including varnished wood, followed by a period where you wanted flat or eggshell effects.

Moving from flat to shiny wasn’t a big problem. You just used trisodium phosphate, TSP, to remove airborne contaminants and slapped the shiny coat over the matte. Matte surfaces have really good microscopic irregularities that allow the shiny paint to adhere tightly to the matte.

Moving from shiny to flat, however, required a lot of hand sanding. You had to “knock down” the shiny surface.

The idea was to create a roughened surface that would allow your new flat paint to lock onto the old, used-to-be-shiny surface. It’s a mechanical thing.

For a short while in the 1950s and 60s, before “latex” (actually acrylic) paint took over the market, paint companies offered flatting mediums because people didn’t want to take the time to sand. These mediums were aggressive (and pretty nasty) hydrocarbon solvents that ate into and softened the shiny surface. Before the solvents fully evaporated, you slapped on your new, flat-paint coat.

Unfortunately, it didn’t work vey well.

Manual sanding was the only method that really worked.

In effect, you’re trying to put flat over shiny. If you used good acrylics, no chemical is going to eat into your surfaces enough to provide tooth for your oil layer. You really have to (delicately and with the hand of a conservator) sand your acrylic layer – to the point where all shine is gone, but not to the point where you have worn off all the pigment. That is, unless it doesn’t really matter if parts of your original acrylic layer has been worn down to the substrate. In fact, that even might make an interesting effect…


(Valerie Smith) #4

I use acrylic paint and then I do the hair in oil. It seems to work for me.


(Curtis H) #5

This is pretty close to what Im doing as well.

The only new thing Im doing to promote adhesion is committing to first applying matte varnish to the underpainting of acrylic. It has been working very well. Like yourself…the hair is so much easier than the non-brush dragging acrylics.