Here are some quick pointers about Primers, Caulking and Paints.
Primers are formulated to penetrate, seal, and provide a good surface for the top coats to stick to. Use them over bare wood, Spackle, and epoxy, or over paint with a chalky, porous deteriorated surface.
Acrylic primers can be used on most surfaces like drywall, but are not recommend on any wood substrate especially on cedar or redwood. That is where oil-based coatings are a must because they lock in these woods’ reddish-brown sap which will leach out over time and leave behind rusty colored stains called “tannin” if the wood is primed with a water-based product.
Pro Painters like Danbury Painting tint primer close to the color of your top coat.
When the primer is dry, Most painters use silicone acrylic caulking—paint won’t stick to straight silicone that is why Danbury Painting uses a more expensive urethane acrylic caulking for greater flexibility and longevity it is also dense and stickier than the cheap stuff, Hey don’t expect a 25-year caulk to last 25 years, but it should last longer than a cheaper 10-year caulk.
Acrylic paint offers superior performance, they don’t harden with age, the way oils do, and they move and breathe with the house, they don’t easily mildew, and they emit fewer V.O.C. which complies with air quality regulations. Acrylic Paints work over both oil and water-based primers.
Oil paint has a place on high end wood siding and in high-traffic areas such as wood steps and certain porch floors because of its superior wear resistance and hardening capacity use oil on steel and cast-iron railings, which benefits from oil’s water repellent properties.