So you have some oil-based paint that you need to paint over? This article will help you make what seems like a daunting task extremely easy.
Sometimes people think that just because their trim hasn't been painted for twenty years that they are dealing with an oil-based paint. This may not be the case, which is why you should test the area you are painting to see if it is oil or latex based.
How to test to see if your paint is oil-based
Pour some denatured or rubbing alcohol on a rag and wipe the surface to be painted. If you can see the paint on the rag, the paint is latex base. If you rub and rub and nothing comes off, the paint is oil-based. If your paint is white and your rag is also white, get some sort of cloth or old t-shirt that is a different color than white so you can see if the paint comes off.
If the paint is latex you can simply paint over it with another latex paint. If it is oil-based you will need to either repaint with an oil-based paint or prime the surface first.
Which primer to use?
You can use a latex-based primer to go over an oil-based paint. So which one should you chose? Generally a primer such as 1-2-3 from Zinsser will do the trick. This primer can be used inside and outside, has superior adhesion to almost any surface and is a stain killer. After the surface is primed you can top coat it with the finish coat of your choice.