Clean and sand the door first and remove any loose finish.
Kilz primer for garage door.
When applying primer just as you did with the sandpaper move in the same direction as the wood grain for best results.
Oil based primer tends to be slower to dry.
Bonding primers come in several formulas.
From hiding stains to blocking odors kilz covers it all.
All interior and exterior surfaces used kilz 2 to prime garage ceiling i just used kilz 2 premium water based acrylic not latex to prime my garage ceiling.
Primer will help protect your door and it will also create a smooth base to help you get better adhesion and truer color from your paint.
With the exception of wood or a stainable fiberglass the rest ought to come with a factory applied coat of primer to protect the door.
Prime a bare wood surface either natural wood or engineered hardboard with a good quality exterior primer such as kilz.
Learn which kilz primers paints and concrete stains are right for your job.
With primer paint solutions for most surfaces from drywall to the kitchen and bathroom kilz primers help block stains seal orders and have a mildew resistant finish.
When painting wood doors you should always use a primer first.