How to Tell If Paint Is Oil

An easy test will tell you whether the existing paint is latex or oil.

When you're going to paint over a wall, you need to know if you're painting over oil-based or latex paint. If you're painting over oil-based paint, you need an oil-based primer before applying a new coat of latex. Fortunately, there's an easy test that does not involve sniffing or tasting paint chips.

Things You'll Need

• Soapy water
• Wash rag
• Towel
• Cotton ball
• Denatured alcohol

Instructions

1. Wash the wall well with mild detergent in an inconspicuous spot. Rinse it with clean water, then dry with a towel. You don't want to get a false result with a dirty wall.

2. Soak a cotton ball in denatured alcohol. Rubbing alcohol works fine.

3. Rub the cotton ball over the clean spot.

4. Look at the cotton ball. If you see paint on the cotton ball, it's latex. You can paint over it with a latex paint. If there's no paint on the cotton ball, it's oil based. You'll need to use an oil-based primer to cover the paint. You can then follow with an oil-based or latex paint.

Tips & Warnings

• You can also use an acetone-based solvent such as nail polish remover.

References

• Seattle PI: A Simple Test Tells You If That Old Paint is Latex or Oil-Based
• Westlake Ace Hardware: How Can I Tell If Something Was Painted With an Oil-Based Paint?