Will Polyurethane Keep Wood From Cracking?

Have you just experienced that frustrating moment when your beautiful project gets ruined because of the wood cracks? They are natural; what can you do?

Sure, there are ways to prevent this. Working with green wooden logs or boards is more difficult than expected. Does this mean we should try everything we read online?

I’ll admit, I’m exactly the kind of person who does this – so I know what works and what doesn’t. But will polyurethane prevent wood from cracking?

The only way to find out is to keep reading!

What is Polyurethane?

First, are you a newbie who is going to do things without looking for help? Then remember that there are many polyurethane-like wood sealants, are they interchangeable?

No, and that’s where I draw the line. Instead of explaining all types of wood seal marks, I will focus on this topic. It will help you spot the differences.

Think of this final product more like a liquid plastic – scratch resistant and resistant to drying out. Polyurethane is anti-porous. It means that air or moisture cannot get in/out.

Although such flexibility can shift its course when exposed to UV light. A change in temperature and humidity can cause a failure of the finish. But that will take several years.

Polyurethane Types

There are only two types, fellows. Some of you already know that sealants come in water or oil base. Well, it’s the same for this sealer.

1. Oil-Based

  • Highly durable
  • An ideal choice for furniture/wooden floor refinish
  • Capable of handling heat better
  • Resistant to water
  • A great option for withholding moisture within wood objects

However, despite the glossy finish you will notice a slight yellow tint. It is suitable for wood that can hide unpleasant color.

2. Water-Based

  • Easy to work with due to less odor
  • Dries faster
  • No yellowing after drying

But it lacks moisture and high temperature resilience unlike oil-based ones. So, does polyurethane prevent cracking without compromising the quality of the wood? You will find out in the next section.

Mending the Cracks: Wood Slabs

Wood panels are the simplest yet most modern way to create projects indoors or outdoors. Needless to say, there are plenty of options to haggle over just to get a corner of your house up a notch.

It doesn’t have to be an over the top kind of design. A wooden dining table top or an office desk in the room is enough. Of course, the advantage of wood boards is to make the piece easier for any project!

From worktops, live edge moldings to benches, doors, cutting boards, etc. you name it. These boards come in a variety of woods, colors and character.

And that, my friend, is enough to make your home ultra-sophisticated without having to renovate the entire interior. Quite a trick – isn’t it?

Wood Checks & Its Treatment

However, each object has its disadvantages. Wood boards are no different. Wood or wood cracks may develop years later due to high traffic, moisture evaporation and shrinkage.

Does this mean you are back to square one with your project? I won’t let that talent go to waste.

Therefore, here you will learn how to prevent cracking of wooden boards using a single polyurethane!

Follow the procedure below carefully to achieve an effective result:

  • If this is an old slab with a split formation, start with sanding.
  • Begin with 80-grit, move it up to 220-grit afterward.
  • The sanding amount is up to you, though more means a smoother finish.
  • Clean the dust particles with a vacuum or a piece of dry cloth.
  • Make sure to remove any mess, or the finish will be uneven.
  • Now take a brush and coat the slab with polyurethane
  • Let it dry well
  • Sand with 500-grit
  • Apply the coat again, let it dry, and sand again. Do this twice.
  • Finally, wet sand the area; clean the residue.
  • Dry the slab overnight.

Mending the Cracks: Wood Slices

I have seen many questions in online forums about wood slices. However, one question is the most striking – how to repair cracked wooden slices?

First, why wood cuts? They have endless artistic purposes. Some examples include coasters, side tables, wall clocks, wall decorations, jewelry holders, and more!

Obviously, this also suggests proper care to avoid creative blocks after facing many cracks in the wood.

Here is how you do that using the dedicated polyurethane:

  • Take tough grit sandpaper; sand both surface sections.
  • Use low grit sandpaper to smoothen the area.
  • Avoid sanding the barks around the edges if there are any.
  • Use a brush to coat the slice all over with polyurethane. It should be a thin layer.
  • Dry it and sand the surface.
  • Apply the coating again if the wood slice is large.
  • Let it dry and wet sand for a finer finish and crack resistance.


Will linseed oil stop wood from cracking?

Yes, boiled linseed oil is an affordable remedy that penetrates the wood fibers. It preserves moisture from the inside for at least a few weeks.

Why does the wood split?

It’s all about the movement of moisture into the grain of the wood. As moisture dries out, wood tends to shrink. It also affects growth rings. This unstable shrinkage causes the wood to split.

How many coats of polyurethane to apply?

Under normal conditions, one can apply two coats and achieve protection from moisture evaporation. If the wood is susceptible to water damage, you can increase it to three or four coats.

Final Word

So will polyurethane prevent the wood from cracking? Only if you know how and what type to apply. Offers better durability than many expensive alternatives.

Now you can protect your work from damage due to natural phenomenon. There is always a way; we humans have made sure of this with various innovative tactics.

Don’t give up yet!


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