In this video I’ll show you the results of painting water based paint over oil based paint. There’s a simple trick anyone can use to identify water based vs oil based paint and avoid making the mistake I made on this job site that I won’t forget. I’ll show you with examples in this video.
This is the biggest mistake to avoid as a painter. Water based paint adheres poorly to oil based paint without an oil based primer and comes off with just a gentle scratch of a fingernail. Peeling on doors can start within days.
I read a horror story where a woman took the time to repaint all of the interior doors for her house. She used a water based paint over an oil based paint and had to scrape and repaint every door within a week due to immediate peeling.
The easiest way to determine whether you’re about to paint over water based paint or oil based paint is to remove a small sample.
How do you remove water based paint? Water based paint is removed remarkably easily using denatured alcohol.
How do you remove oil based paint? Oil based paint is removed using either mineral spirits, paint thinner, acetone, or paint stripper. Mineral spirits can be found in an odorless variety and does a good job of removing fresh oil based paint, but doesn’t work as well as the heavier duty noxious chemicals like acetone or paint stripper. For old, difficult to remove oil based paint, the best bet is to use acetone or paint stripper. However these will leave a sticky residue, unlike removing water based paint with denatured alcohol which leaves no residue.
How do you paint over oil based paint? Oil based paint adheres well to other oil based paints. If applying water based paint over oil based paint, an oil based primer like Kilz Original works well. Even though the primer is oil based, it’s designed to bond to water based paints.
I’ve used Kilz oil based primer in the past to paint over wall paper and varnish and polyurethane for great results.
