Unfortunately, no, you cannot gesso over an oil painting. The gesso might go on cleanly, but ultimately it will simply not stick and start peeling off after a little time. The only thing that you can effectively paint over oil with no special preparation is going to be more oil paint.
Today I’ll tell you a little about painting over oil paintings. We’ll discuss how to go about painting over an oil painting, whether or not you can paint acrylic over oil, and if any water-based paint at all is suitable for painting over oils.
Oil is a little bit picky about what you safely can put over it, as you are about to see!
How do you paint over an existing oil painting?
If you want to paint over an existing oil painting, then the first step is going to be removing the varnish. You can do this with a little turpentine, dabbed onto a lint-free cloth, and you’ll want to gently rub it into the varnish in quadrants until you’ve given the entire painting a light coating and rubbed the varnish off on your cloth.
After this, to start taking down the oils, Wipe it down with half an onion first. This sounds weird, but it will loosen up the paint enough for the next step. Once you’ve onion up the paint, wipe it down with walnut or linseed oil, depending on which was used with the painting originally.
Spread the dissolving oils around a bit and wipe them up with some paper towels and after this, if you want to create an opaque surface for your new work, then paint on the canvas with a layer of burnt umber.
Stow it away to dry for 2 to 3 weeks scrape it lightly with a razor. If it’s a bit powdery, it’s ready, but if it simply strips the paint then let it dry another week and test it again. Once it’s powdery, your new paint will stick to it and you should be okay.
Can you paint acrylic over an old oil painting?
Unfortunately, this is not something that you can eawsily do. Painting acrylics over oils might like fine for a small period of time, but eventually it’s always going to flake or peel right off. You can do it the other way around, painting oils over acrylics, but acrylics over oils is simply doomed to fail.
This is because oil keep changing as time progresses. While acrylic hardens into a semi-plastic that is fairly impervious to the test of time, oil keeps going through slow chemical processes that make it unsuitable for the added acrylic. Simply put, the surface isn’t sound.
Conceivably you could sand the varnish a little to get some extra sticking power from your acrylic, but this is not really practical and even if you go the acrylic to stick, it might not look very good once you got that second coat of varnish on.
So, as a general rule the case is most going to be oil over acrylic but never acrylic over oil!
Can any water-based paint go over oil?
I did a little more checking and I’ve located a method for using water-based paints over oil. I’ll have to experiment with this a little but I’ll warn in advance, it does take a bit of preparation. The biggest problem that we have with water-based paints or acrylics over oils has to do with getting it to stick properly. If the oil painting is properly dried then it should have undergone enough chemical changes for this trick but again, it’s something I’ll need to test a little and I’m just sharing it so that you can try it on your own as well.
You want to start off with a fine-grit sandpaper, such as 180 – 220 grit, and sand down the surface of the oil painting until it is much less glossy. At this point, you’ll want to clean it with TSP, which is short for Trisodium Phosphate.
Soak some up in a sponge and make two passes over the painting, in order to clean the grit from the sanding and the painting overall. Let it dry and then you will want to prime it with a water-based primer. When the surface looks smoother out and is primed all over, then you can attempt to use your water-based paint or acrylic and it might just stick perfectly.
Give it a try and see what you think… I’ll be playing with this myself this weekend!
A quick recap before I go
Today I’ve answered the question ‘can you gesso over an oil painting’ and while that won’t work, if you want to paint with a water-based paint over oil, you might be able to get it done with a bit of sanding, cleaning with some TSP, and then priming before attempting to paint on the surface. While it’s not generally recommended to paint with water-based over oil, this little trick might help you to do just that.
If you’d like to read more about the opposite type of painting, being oil over acrylic, then you can find a wonderful 3rd party article here. It will tell you a little more about why it works and how it is done, so be sure to give it a read.
In the meantime, I need to prepare to experiment with the water-based paint over oil… it’s looking like I’ve got a fun weekend ahead!