Best Knot Blocking Primer

The last thing you would want is pine knots bleeding through paint on your furniture. These pesky imperfections can ruin the look of your carefully painted piece, leaving unsightly marks and discoloration. That’s why it’s super important to have the best knot blocking primer as one of your furniture painting tools and supplies.

What primer should you use to prevent knots from happening? Which one will give you the best results and save you from bleedthrough mishaps? Let’s look into the top knot blocking primer options and find the one that best suits your needs.

applying primer onto wood knots on furniture with text overlay

But why do knots always show through paint? First, knots are imperfections in the wood that are usually darker in color. This makes them highly visible and contrasting to the surrounding wood. If you simply paint over it, the darker knot can still show through, especially as the paint ages and thins out.

They are also denser, which can lead to differences in how it absorbs paint compared to the rest of the wood. Plus knots can sometimes contain sap, which can cause discoloration. All of these factors contribute to knots showing through the paint.

So what do you have to do to stop knots from ruining your paint job? Of course, you don’t want to waste time and effort on painting over knots again and again, as well as waste paint and other resources. That’s where a good knot blocking primer comes in.

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How to Stop Knots from Bleeding through Paint

We start with properly preparing furniture for painting. This means sanding down any knots or imperfections to create a smooth surface. If you skip sanding for paint prep, it will also be hard for both the primer and paint to adhere properly. This can result in peeling and flaking, making it easier for knots to pop up.

sanding and applying primer onto wood knots before painting

When you’re done with all that, it’s time to prime wood for painting! And yes, you need to use a knot blocking primer to stop knots from bleeding through your painted furniture. This type of primer is designed specifically to seal the knots, creating a barrier between the knot and the paint.

Using a regular primer may not be enough to stop knots from showing through, so it’s important to invest in this specific type of primer for painting furniture. It will save you time and frustration in the long run. Instead of having to repaint multiple times, a good quality knot blocking primer will do the job in one go.

Best Knot Blocking Primers

So what are the best knot blocking primers on the market? We have tried and tested these top picks, and while they all do a great job at sealing knots, some may have added features that make them stand out. Read on to see what you can expect from these knot blocking primers.

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BIN Shellac Based Primer

The first knot blocking primer on our list is BIN shellac based primer. This primer can be rolled on or sprayed from the spray can version, giving you flexibility in application methods. You may prefer using a roller or brush, so go for the can version, but if you want a quick and easy spray-on option, then the spray can would be perfect for you.

If you do use the spray can, be aware that the primer dries very gritty, so it’s important to sand it smooth before proceeding with painting. Of course, we want a flawless base for our paint, and sanding will give us just that. However, this added step may be a drawback for some, as it adds more time and effort to the process.

Another great feature of this BIN shellac primer is that it can be tinted to match your paint color. This makes it easier to cover the primer with your paint, especially if you’re using a lighter color.

You can also use this tinting feature to help you identify which areas have been primed already, preventing missed spots. If you want to know the step by step process of applying this primer, here’s how to use BIN shellac primer!

Pros

Can be rolled on or sprayed for application flexibility
Can be tinted to match the paint color for easier coverage
Can help identify primed areas with tinting feature

Cons

Spray can version dries gritty, requiring sanding for a smooth finish
Additional time and effort needed for the sanding step

Clear Shellac in Spray Can

The clear shellac in spray can is another awesome option for a knot blocking primer. I personally love it, as it’s quick and easy to apply with the spray version.

Plus, you don’t have to worry about sanding it smooth since it dries smoothly on its own. You get to save time and effort in the priming process, making it perfect if you’re short on time or just really want a hassle-free experience.

priming furniture with Clear Shellac in a Spray Can

Here’s our list of the best spray primer for wood to learn more about the features and benefits of this spray primer!

But one thing about clear shellac is it’s clear, so you won’t be able to see if the knots have been completely blocked. It can be quite hard to tell if the primer has done its job. If you prefer being able to visually see the knots being covered and blocked, then this clear primer may not be the option for you.

If you prefer using a brushable version of this clear shellac primer, you can also go for that. It may take longer to apply compared to the spray can, but if you’re more comfortable with using a brush, then that’s not a problem.

Pros

Quick and easy to apply with the spray version
Dries smoothly without needing sanding
Available in a brushable version for those who prefer it

Cons

Clear color makes it hard to visually see if knots have been fully blocked
Brushable version may take longer to apply compared to the spray can

Kilz Primer

The next primer on our list is Kilz Primer. It has a red can, making it easy to spot in the paint aisle. This oil based primer blocks knot stains very well, so you can be sure to get the coverage you need to stop them from showing through your paint.

However, it’s not without its drawbacks especially when compared to the knot blocking primers we’ve mentioned above.

A major drawback is that Kilz Primer doesn’t dry to a hard sandable finish as quickly as the shellac primers do. This means you may need to wait a while longer before sanding down any rough spots. If you’re in a hurry to get the painting done, this may be frustrating for you. But if time isn’t an issue, then Kilz Primer may be the reliable option you need for knot blocking.

Pros

Blocks stains very well
Easy to spot in store with its red can design

Cons

Doesn’t dry to a hard sandable finish as quickly as shellac primers
May require a longer wait time before sanding, adding to the total paint prep time

Zinsser 123 Primer in Spray Can

If you’re more comfortable using a spray can, then you will want to consider the Zinsser 123 Primer. It’s no doubt a hard worker at blocking stains from wood knots. The spray can also has an oil based formula, similar to the Kilz Primer above.

What sets the Zinsser 123 apart is its quick drying time of only 30 minutes. That’s right, you can get your project done in no time with minimal waiting around for the primer to dry. You get to start painting sooner, which is always a plus.

Pros

Available in a spray can for easy application
Quick drying time of 30 minutes

Cons

Oil based formula may have a strong odor

Waterbased Primer

If you want to avoid the strong smell and fumes of these oil based primers, then a waterbased primer is the way to go. Not only does it have a more mild odor, but it also has the added benefit of being non-toxic and environmentally friendly.

Waterbased primers do require longer waiting times between coats. It may take 4-8 hours for the primer to fully dry and be ready for another coat. So if you’re on a tight timeline, this may be hard to work with.

applying multiple coats of Dixie Belle Boss primer onto furniture

You will also need to apply multiple coats of waterbased primer to actually block the stains from wood knots. Again, this adds more time and effort to your furniture makeover. It’s not exactly a deal breaker, but if you’re looking for quick and easy, you might want to consider the oil based options.

The best waterbased primers for wood knots include Dixie Belle Boss and Zinsser 123 primer in the brushable can. Both of these primers have shown great results in covering and sealing knots, without the added strong odor. Just remember that patience is key when using them.

Pros

Mild odor compared to oil based primers
Non-toxic and environmentally friendly

Cons

Longer waiting times between coats
May require multiple coats for effective knot blocking

There are both oil based and waterbased options to work with when it comes to knot blocking primers. Each has its own set of pros and cons, so take the time to consider which would work best for you and your project.

If you’re in a hurry and want quick results, then the spray can versions of clear shellac or Zinsser 123 may be your best bet. But if you’re more concerned with avoiding strong odors and fumes, then waterbased primers may be what you need. With all these choices, there’s no excuse for those pesky knot stains to ruin your paint job now!

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Best Knot Blocking Primer

How to Stop Knots from Bleeding through Paint