Sanding Primer Before Painting Wood – A Complete Guide
Primer can be an important part of painting a product as it can help improve adhesion, cover up existing coatings, and more which we cover in our article on paint primer.However, after applying primer there are often still a lot of questions like should I sand after applying primer. This is especially true when priming wood whether it be trim, molding, or wood cabinets. Today’s guide will cover sanding wood that has had primer applied.
Why Use Primer on wood
Paint doesn’t adhere well to wood so in order for a painted coating to be applied and stay on a wood surface priming the wood first is a great idea though not always needed. The primer on wood will also help reduce the amount of topcoat paint you need for your wood project. While applying primer first is helpful, there are some reasons you may need to sand before painting primed wood.
Do I need to Sand Primer on Wood before my Topcoat
You do not necessarily have to sand wood that has had primer applied. The problem that occurs when you apply primer to wood is that the grain of the wood can rise due to paint interacting with the wood and swelling the fibers. This causes a raised grain appearance which tends to be duller appearing when the topcoat is applied. This is sometimes not a desirable appearance. Some times people do like the look of raised grain. However, if you do not want your wood to have a duller appearance (raised grain) then you will typically want to sand before you apply primer.
How to Sand wood with Primer on It
The goal of sanding wood that has primer on it is to smooth down the grain that has risen while still leaving the primer intact so you do not lose the added adhesion that the primer will provide for the top coat. To sand wood with primer on it you should consider a finer grit sandpaper (like a 220 grit sand paper). Additionally, you should consider using an orbital sander as it will not alter the appearance of the natural wood. You may find you will need an additional finer grit sandpaper. Ultimately the goal of the sanding if trying to get rid of raised grain should be a smooth wood finish. If you are looking for a better overall finish the smoother the better which can at times require sanding the wood with a primer on it with up to a 600 grit sand paper.
Sanding Wood That was Previously Painted
If your wood has been previously painted you will typically sand but not necessarily to fix issues with raised grain but to help promote adhesion. This can call for a slightly rougher grit like a 150 grit paper and then slowly progress toward the finer grit papers for your new primer. You should find that repainting the wood will not cause it to raise the grain if it was previously sanded after primer.
For your finish to be vibrant and not dull sanding after primer will ensure that the finish is not excessively dulled when you apply your paint top coat. You will typically use finer grit sandpaper and aim to achieve a smooth wood finish so that you get a fine appearing wood finish when you apply your topcoat.