The question is a common one, “Do I have to use primer first before painting?”

To answer that question you must first discover what kind of paint is on the surface of what you want to re-paint.

First, it’s vitally important to determine what kind of paint is currently on the surface you want to paint. In the past, discovering this wasn’t easy. That’s why I developed a special tool that will determine what type of paint you are dealing with. It’s called Tru-Swipe and it couldn’t be easier to use!

We hope we can deliver some information that will clear up the issue.


Back in 1979, it was ok to use lead-based paint products. But when they were banned everyone began using oil-based paint. Now, the EPA requires regulation of VOCs or volatile organic compounds. In addition, water-based paint technology grew and created an excellent product for painting, but just not on top of oil-based paint.

With our new ‘Tru-Swipe’ method, you simply use the cloth to wipe over the painted area. If it dulls the paint you know it’s water-based paint. But, if it only cleans the surface you have an oil-based surface. EASY!

10 second can save you thousands!

  • Just Tru-Swipe the painted surface back and forth 3-4 times and examine the pad to see if the paint was removed.
  • If the paint is removed where Tru-Swiped, you know you have a water-based coating that does not need to be primed before painting. Saving you time and money, while knowing you have the right paint for your project.
  • Oil-based painted surfaces will not break down or degloss when using our specially formulated Tru-Swipe. A clean reading shows the painted surface is oil-based and will requiring sanding and an oil-based topcoat, or sanding, priming, and a water-based topcoat. When water-based paints are painted over oil-based paint you end up with unsightly catastrophic failure as shown.

Check out Tru-Swipe Website or for questions or orders: (619) 586-5683

OK, now that you know what type of paint you’re dealing with you can proceed.

If you put water-based paint over oil-based paint the results are disastrous. Within just a few short days or weeks you’ll notice that the paint is starting to peel and flake away. And, you’ll end up doing the job again.

If you don’t have time to get the Tru-Swipe product you can use a bit of methylated spirits on a rag and wipe at a small section of your wall. If the cloth gets a bit of the wall color on it then you’re dealing with water-based paint. You can paint over that with another water-based paint product without an issue. Always make sure you take the time to tape off anything you don’t want to get paint on. In addition, make sure your surfaces are clean and dry.

Do I use a primer first if I discover I have oil-based paint?

If you still wish to repaint your existing oil-based wall with water-based paint, sand back the wall with sandpaper to remove the sheen. Then, apply a good primer. (Choose a primer that is best suited for your  substrate.) Next, allow it to dry, and then coat with your new water-based paint.

Local San Diego Painting

In Conclusion

It is important to know whether you are dealing with oil-based or water-based paint before starting a job. Otherwise, you could end up with a project that will then require more time and money.

If you are not sure which type of paint your walls have been painted with in the past, call us or order some Tru-Swipes! We can help identify what type of paint was used so we can provide advice on how to properly clean them or start painting them without ruining all previous work.