Oil base paint – How do I know?
The rule in painting has always been, if it was painted with an oil base/alkyd paint, you need to recoat with an oil base/alkyd paint. With the new Canadian VOC regulations regarding paints and primers, the old rules will have to change. Soon oil base/alkyd paints will no longer be available.
The problem then is two-fold: 1/ how do you know if the surface was painted with oil base / alkyd paint and now, 2/ how do you recoat it?
Generally speaking, if you can get a chip of paint from your surface then old oil base / alkyd paint will be brittle. Also, as the paint breaks down in the sun, oil base / alkyd paints tend to chalk more than latex or acrylic paints.
However, the best method to test your paint is to use a chemical wipe.
Nail polish remover with acetone or methyl hydrate will dissolve latex and acrylic paint. If you wipe the painted surface with a clean rag dipped in the chemical and the paint comes off on the rag (more than just the surface chalk) then you have acrylic / latex paint. If not, you have oil base / alkyd paint.
Knowing this difference is important; now you can determine which products to use to recoat.