The following blog post will tell you why you should sand after applying primer on wood.
Hey, I’m a painter by hobbyist and I’ve been painting my wood furniture or wooden boards for quite a long time. If you question me about priming as every professional recommends. I would say, yes you must apply a primer coat. It’s an important part of a painting job essentially when there is a block of wood to paint over.
In this blog, I’ve written guides on choosing the perfect grit sandpaper as well as have published content about why you should prime a piece of wood before painting.
This is why you should sand after priming.
- After priming wood to prepare the base coat, sanding is often needed to create some holes into the top surface. By doing so, the primed area grows into a larger surface for the paint to hold onto, which results in better adhesion.
- With regards to bare wood, the purpose of sanding after priming is all about ensuring that your paint finish will not get excessively dulled but achieve aesthetically pleasing end results. As It knocks down the wood grains that otherwise can make things up when applying the topcoat.
In case, if you’re clueless about choosing the right sand grit number, use 180-220 grit paper for a primed surface to get the best results.
3 Reasons why sanding after priming is important?
- Provides a smooth flat base- A smooth and even surface can be achieved by sanding a primed surface, eliminating brush marks and extra globs. In reality, it is essential to reduce bumps and dents when you apply the paint.
- Knockdown wood fibers- When we prime bare wood, wood fibers rise up to the surface, can reduce the effectiveness of the topcoat, and make it appear blotchy. Sanding helps these grains knock down and establish a smooth finish for the topcoat.
- Create holes on a surface (when the surface is too smooth): Sometimes when priming on surfaces that already have a base coat of a stain, varnish, or a coat of paint. in fact, a surface that is already smooth. Sanding after applying primer will create holes into the surface to hold onto the topcoat.
How long after applying primer should I sand?
Without knowing the type there is no one-sentence answer to this dilemma. As it depends on the type of primer you’ve chosen. Since the drying time varies from one primer type to another.
- If your primer is water or latex-based, then expect it to be cured completely in 5-6 hours. Following that, you may be able to sand down the surface so it is smoother before applying the topcoat.
- If It is an oil-based primer. Then, you should wait for about 12-15 hours before you can sand the surface. Be sure the primer coat has completely dried by touching it.
Note: There are many exceptions to the time period, such as moisture or cold weather that would increase your waiting time. As well, how you apply coats will also have direct impacts.
HOW TO SAND WOOD WITH PRIMER ON IT
Sanding a primer’s coat is straightforward. If you have sanded anything previously, you shouldn’t have any difficulty.
- Step.1 Make sure the primer is dried to the touch. In the first step, make sure the applied primer has dried to the touch. Since it is not just about drying but also getting the paint to go deep into the wood grains, it would take extra time.
- Step.2 Use a finer sand grit 220. Using a finer sand grit 220 is ideal for many tasks based on my experience in doing such jobs. However, sometimes I use 180 grit when I need to do rough sanding.
Or if there is a larger piece to be sanded down. You have the option to go with the power sanders, orbital sander is the most preferred choice. Because it sands a surface lighter than belt sanders.
You can read here the difference between orbital sander vs belt sander.
What happens if you don’t sand?
Avoiding sanding after applying primer is one the biggest mistake most people make. That causes problems in the long run.
- Avoiding sanding will create many ups and downs in the topcoat. It happens because of the wood grains that rise up when expose to any liquid. And here, primer is the trigger. Therefore, it becomes essential to sand down.
Similarly, avoid sanding on a base coat of primer applied on an already painted surface. Something which is already stained or has a layer of the coat covering the wood grains. You still need to sand down it once you applied the primer. The reason behind this is, a surface that is too smooth can not hold the topcoat unless you use sand grit to create a rough surface: to hold the paint firmly.