Sometimes you want to brighten the look of the furniture or bring some new color to a wall that’s begun to yellow. Before you put a paintbrush to it, you will want to know what exactly you are painting over.
The paint can be either water-based(latex) or oil paint, but you should be careful with painting over it if it is the second option. If you try to use water-based paint over oil paint, it can cause it to crack and peel. Any damage to it can make quite a mess of all your hard work.
This can end up ruining your wall, furniture, or painting, and you will have to go over it again. If you keep reading with me, I can show you how to paint over it step by step.
How do you paint over Oil Paint?
The simplest solution would be to grab oil-based paint to paint over it since water-based paint won’t adhere to it. Since this would refresh the paint and seal in color. Though this is the easiest option, it isn’t the best solution for all your needs.
After all, maybe you prefer latex to avoid the strong fumes oil-based paint releases or because it dries faster or doesn’t yellow. Perhaps you want to make sure the old paint doesn’t show through your new layer of paint.
Regardless of the reason, here are the steps to follow:
- Make any repairs if needed.
- Confirm if it is oil or water-based paint.
- Sand with fine-grit sandpaper.
- Clean the surface of any dust or grime.
- Use a Primer on the surface.
- Finally painting over the old paint with your new layer of paint.
Repair any cracks and damages
Before you paint over anything, make sure there aren’t any damages or cracks. Painting over cracks won’t make it disappear, so it can worsen the damage, and it will show.
Especially if you’re painting over something that is outside in the elements. Sometimes it might be better to replace it instead of painting over it if the damage is severe enough.
Check if your paint is water or oil-based
After confirming there are no damages to the material. The first step is to verify if you are dealing with oil or water-based paint if you didn’t paint it yourself. It’s a straightforward process.
- Get a rag
- Gently wet the rag with acetone or methylated spirit
- Rub over a small area.
- If the colors stick to the rag, it is water-based paint if it doesn’t, it is oil-based.
NOTE: If it is water-based, you could use either water-based or oil-based paint to paint over it. I would still use primer beforehand. If it's oil-based, it will need a few extra steps to make sure it goes smoothly.
If it is Oil based, You Need to Sand it
If it is oil based paint, you would want to sand a wall or furniture for the primer and paint better adhere on the surface. When you pick your sandpaper, make sure it’s a fine grit one. An Abrasive Paper with 180 to 220-grit works well for this. I like it in form of blocks like on the image below.
Don’t be too rough when sanding it, as you are just getting the surface layer gloss off. If you’re too harsh, the scratches will show through the primer and paint. You would want to avoid this, so just do enough sanding so that there isn’t any gloss over it.
NOTE: You do NOT have to sand an actual oil painting on a canvas if that's your goal, so you can safely skip this step.
Clean Sanded Surface of any Dust or Grime
Now that you sand it, there is likely a bit of dust everywhere. When you’re about to paint over something, you would want to clean the surface. So your next layer of paint and primer doesn’t collect dirt, grease, or dust.
Since this can alter the color and cause smudges in the final product. So if it’s filthy, you will want to clean it with Trisodium phosphate(TSP), which you can buy.
Here’s how to do it:
- After sanding, make sure to dust it off with a soft brush.
- Grab a bucket filled with one gallon of water, mix the solution with 1/4 cup, or use 1/2 cup of TSP if filthy. As well as have a bucket of just regular water.
- Grab a sponge and dip it into the mix, making sure to wring it out, so it’s just damp.
- Then begin to gently scrub from the bottom up to remove any dirt and grime. Try to avoid letting it dry since you wouldn’t want the TSP to dry on it.
- Then use a clean sponge to clean off the solution from the area with water, then air dry.
If it’s a painting on a canvas that you cherish, you can use a soft brush to dust the painting itself. Be gentle with it, and make sure the brush is soft to reach its crevices. The bigger the brush, the better to quickly dust it off for your touch-up.
If you feel it needs a deeper clean, you can use an olive oil-based soap to gently clean it with a damp sponge. Then very gently clean it off with a brush.
NOTE: Do not use feather dusters on your oil paint, as small bristles can scratch up your paint.
Use a Primer on the surface
Depending on what you’re using to paint over, you can use a water-based primer if you plan to use latex paint. This will allow the latex to adhere to the material with no issues. That is also the point of sanding the material to have that base.
If using oil paint, then you would want to only use an oil-based or water-based primer. The point of a primer is to help the material adhere to the surface. As well as help protect it from stains and environmental damages. For best results, make sure to do two coats of the primer and let it dry between coats.
TIP: Make sure the primer is thoroughly dried before you go on to painting with your colors. Otherwise, it might bubble or slide off, which you might have to sand it off and repaint to fix.
If you have followed every step, you can use latex over the oil paint as the primer will let it adhere to the base. With a water-based primer, you can use latex and water-based acrylic paint to paint over the oil paint. Though it might be helpful to keep in mind the location of where you are painting.
Latex has the benefit of never yellowing, so it will always retain its colors; however, it can still get scuffed by spills. While oil-based paint is more resistant to stains from spills but does yellow with time.
Also, if the paint is for the interior would be the best match to use interior paint. Same if painting outside exterior would be best.
TIP: If you're touching up a painting, it is best to use the same base paint as the original so oil painting with oil paint.
What happens if you paint over oil paint directly?
If you try to paint over oil paint directly with water-based paint, it will begin to crack and peel when it dries. As the paint won’t adhere to it, any bump will cause the water-based paint to chip off. In that situation, it would be best to peel it all off and restart the process again.
Can you directly paint over varnish?
If your canvas or furniture has vanished, you would want to use varnish remover before painting over it. The varnish will cause the same problems as oil paint, so it needs to be removed before anything. Thankfully it’s an easy process as many removers won’t damage your paint.