Sanding is a vital process in woodworking projects as it allows you to remove the imperfections of the wood and create a smooth surface that makes it look much better than a surface that hasn’t been sanded.
While sanding the surface of the wood before painting, after painting, before staining, before finishing, and after finishing is a common practice most of the time, we have noticed a lot of questions about the specific case of sanding between coats of stain and whether it’s necessary or not.
So, is it always necessary to sand between coats of stain?
While it’s not completely necessary to sand between coats of stain, doing so will improve the bond between coats of stain and produce a better-looking finish, especially if you are using a water-based stain.
As oil-based stains don’t cause grain raising (the swelling of wood fibers) like water-based stains do, sanding between coats of stain is less significant for the quality of the finish but still recommended.
Next up, we will be diving into why we recommend sanding between coats even when it’s not necessary, the tips and tricks you can use to sand your wood between coats of stain, and the stain types where sanding between coats is an absolute necessity.
Why Should You Sand Between Coats of Stain?
Despite being a vital process for almost all woodworking projects, sanding most likely isn’t your favorite activity as a woodworking enthusiast as it may get slightly tedious over time due to the amount of effort it requires.
While we completely understand if you would like to avoid sanding as much as possible, sanding between coats of stain even when it’s not necessary can have incredible benefits for the finish of your project.
The first and most visible benefit of sanding between coats is how much better it makes the stain look.
While the staining process can create some unwanted bubbles and bumps on the surface of the wood, you can quickly get rid of these imperfections by sanding between coats of stain and create a smooth surface for the final coat.
The second benefit of sanding between coats is that it significantly improves the strength of the bonds between coats of stain.
Stronger bonds between coats of stain mean that they are more likely to stick to each other and hold, preventing them from easily coming off the wood.
How to Sand Between Coats of Stain?
While sanding between coats of stain is beneficial when done right, doing it wrong will cause the stain to become damaged.
Choosing the correct technique, sanding tool, and sandpaper grit are all vital factors for this process to go smoothly, which is why we will be talking about everything you require to complete this journey successfully.
First off, let’s take a quick look at the list of materials you will need.
- 220 or 240 grit sandpaper
- Hand sander (optional)
Here are the steps for sanding between coats of stain.
- Start by loading your hand sander with 220 or 240 grit sandpaper. If you aren’t planning on using a hand sander, you can skip this step. Using your bare hands for sanding is completely fine for this process.
- Sand the surface very lightly to avoid damaging the stain. Remember that the goal is to remove imperfections such as bubbles and bumps, not to sand the wood down. If you sand too harshly, you will take too much of the stain off.
- Lightly wipe the surface with a rag to get rid of any leftovers that appear on the surface as a result of the sanding process. These leftovers usually show up in the form of white powder that you can easily clean off.
- Apply the next stain coat and wait for it to dry, then repeat steps 2 and 3 until you apply the final coat. It’s vital to wait for the current coat to dry before sanding and applying the next one – as the current coat will remain wet for a long time if you don’t.
Which Stain Types Require Sanding Between Coats?
Whether sanding between coats is a necessity or not depends on the type of stain you’re using, as these stain types are more prone to creating imperfections.
Let’s quickly go over all types of stains and see whether they require sanding between coats or not.
As water-based stains cause grain raising, which is wood fibers swelling due to coming into contact with water, using a water-based stain requires you to sand between coats to remove these imperfections and produce an aesthetically pleasing finish.
Oil-based stains do not require sanding between coats as they don’t cause the problem of grain raising as water-based stains do.
Simply wiping the current coat of an oil-based stain with a piece of cloth before applying the next coat is more than enough to prepare it for application.
While polyurethane stains can be both oil-based and water-based, neither of these variants require sanding between coats.
As the main strength of polyurethane is that it dries extremely quickly, wiping off the excess with a piece of cloth, similar to how you do with an oil-based stain, is enough to prepare it for the next coat.
There are many mixed opinions in the case of gel stains, with some advocating for simply wiping the excess stain off; and others thinking that sanding between coats is necessary.
Our opinion is that sanding between coats is certainly necessary to achieve a high-quality finish with gel stains.
As always, if you are in doubt, remember to follow the instructions of the manufacturer.
Lacquer and Varnish Stains
Both lacquer and varnish stains don’t require sanding between coats, as every coat of lacquer and varnish stains dissolves into the previous layer.
Simply put, you can think of the successive application of coats of lacquer and varnish stains as a single coat that gets thicker with every application.
The bottom line is that sanding between coats is necessary for water-based stains and gel stains; and optional for oil-based stains, polyurethane (both oil and water-based) stains, lacquer stains, and varnish stains.
Can You Sand Again After Staining?
Sanding after applying the last coat of stain is not necessary, especially if you have sanded between coats, and is usually not recommended due to its effects on the color of the stain.
That being said, you can very lightly sand the last coat with extra fine sandpaper (minimum 320 grit or higher) if you feel that the finish requires further smoothing. On the other hand, as you can easily damage the stain if you aren’t careful, it’s best to steer clear of sanding the last stain coat if you don’t have experience with it.
It can also be helpful to read the instructions of the stain you are using to learn about what the manufacturer suggests, as you can usually find instructions related specifically to sanding to guide you in the correct path.
Even though sanding between coats of stain is only necessary for some stain types, we highly recommend doing so with any stain as it has incredible benefits for your project.
Regardless of the type of stain you use, the difference between a surface where you have sanded between coats and one that you haven’t is easily noticeable from the quality of the finish and the lack of imperfections.
If you have a project that you want to be absolutely perfect, you definitely won’t want to miss out on sanding between coats of stain to take it to the next level.