Why is primer necessary?

Boredom at its finest: sitting around and watching paint dry.

But if you understood the fascinating process that happens as paint transitions from liquid to a smooth, glossy coat, you'd be intrigued.

This transformation owes a lot to primer. Without it, the surface beneath the paint may not allow it to dry properly. The result could be blotchy, uneven sheen, brush marks, or peeling. Primer ensures a smooth and even base, helping the paint adhere and dry perfectly.

Think of the comparison between clothing and underwear. While clothes cover us for modesty and warmth, they also express our style, personality, and color. Paint can serve the same purpose. Underwear, however, works as a layer between the skin and clothing. Just as underwear shapes the body to make clothes fit better, primer smooths out imperfections on surfaces so the paint looks and lasts better.

Now that you understand the importance of primer, the next question is: how do you choose the right one? It all comes down to the type of paint you plan to use.

Prime This

Paint consists of three main components: pigments that give it color, binders that hold everything together when the paint dries, and liquid solvents or 'carriers' (such as water or oil) that make it fluid enough to spread or spray. As the solvents evaporate, the binders, pigments, and other additives like thickeners and fungicides remain behind.

In the past, oil-based solvent paints were regarded as the best and most durable. However, environmental concerns have led to a decline in their use, while advances in latex paint technology have made water-based paints more popular. Water-based paint releases fewer toxic fumes, dries quickly, is more flexible (with less cracking), and, importantly, can be cleaned with water.

Some professional house painters and artists still prefer oil-based paints and primers. Dan Gallagher, a decorative painter in Los Angeles, noted, 'I would not use water-based primers over raw wood unless I absolutely had to. Manufacturers have reformulated water-based primers in the last five years, and while they claim to block stains and prevent wood knot bleeding, I haven’t seen it work effectively yet.'

Gallagher also mentioned that oil-based primers are best for high-traffic areas like doors, windows, and cabinets. Water-based primers are suitable for areas with less wear, like crown molding. He added that water-based paint can usually be applied over oil-based primer, but it's always best to follow the manufacturer's instructions. In short, read the label.

Here's another way primer is like underwear: there are times when it’s not necessary. For example, when you’re applying the same type of new paint over a solid, existing layer of paint, using primer may not be crucial.

Always use primer on the following surfaces:

Despite the wealth of information on paints and primers, seasoned painters still often consult experts at high-quality paint stores. You might want to do the same. In the meantime, you can find even more helpful details through the links on the next page.