Sanding Convex Surfaces / Curved Wood – In 3 Ways

Sanding curved surfaces is not something that you finish with a single tool. Depending on the curve, you’ll need custom tools for the perfect finish. That’s why we will give you some tips for sanding convex surfaces or concave surfaces.

sanding convex surfaces

What is Sanding Convex Surfaces?

A convex surface is a surface that is bent out or extending outward. You had probably faced a lot of situations where you had to sand such surface. But not knowing how to sand convex surfaces can be a real issue.

However, this is no big deal with the right tools in hand. There are many sanding tools like a belt sander, disc sander, orbital sander, etc. Some of them will sand some portion of the U-shaped surface. But you’ll need special tools for curved surfaces.

How to Sand Curved Wood Surfaces?

Sanding curved surfaces will only give you 2 different situations. One is to smooth a convex surface and another one is to smooth a concave surface. Also, it can be irregular curves and you’ll have to improvise. Let’s see some cool ideas that we can use for different exteriors and interiors.

How to Sand Convex Wood Surface

a) With a Soft Hand Sander

hand sander
Using a Soft Hand Sander and A Hand Sanding Block for Convex

Soft Hand Sander: Check on Amazon=> +Sanding Block: Check on Amazon>

First of all, you can use hand sander in this case. It’ll give you precise sanding and more control over the surface. To sand small pieces or the wooden parts that need more attention, you can use different shapes of sanding blocks. From your local hardware store, you’ll find those blocks. However, you can make your custom-shaped blocks to finish custom projects. The only problem is that this method can take a lot of time.

b) Sanding by angle grinders

angle grinders
Sanding by angle grinders +special grinder heads =>

Secondly, you can check out angle grinders. You might think it removes material and how you can use it for sanding. But isn’t sanding is all about removing materials in a controlled way? You can use special grinder heads to sand as well as remove a lot of material in a very short time. But you will have to be careful because this is a very aggressive tool.

C) Using a Random Orbital Sander with Polystyrene

Lastly, you can consider random orbital sander with a little bit of modification.

This is the best trick to sand convex surfaces in a short amount of time. Usually, you attach a sanding paper with a random orbital sander.

But in this case, you will need to add Polystyrene foam in the middle. Spraying an adhesive on both sides of the Polystyrene will keep the sandpaper attached. After that, use the orbital sander like always and the foam will adjust the curves.

That’s how you’ll be able to sand irregular surfaces that are curved outwards. But it won’t help you much with concave surfaces and we’ll show you some other tools to do that.

How to sand Concave wooden surfaces

a) Using a Tailed Sanding Apprentice
tailed sanding apprentice

The first recommendation is to use a tailed sanding apprentice. The flexible shafts will allow you to sand holding the tool like a pencil. This will allow you to sand with more attention and precision. Small wooden projects and custom jobs are the perfect situations to use such a tool.

b) Using Sanding Drums Attach to the  Drill Head

If you haven’t any Drum Sander then you can also purchase some Sanding Drums, then attach it with a Drill. Get it from the below link:

Then, you can look for the sanding drums which can only support some specific concave surfaces. The main advantages of the sanding drums are its flexible rubber drums and availability in different sizes. That’s why you can use it to sand almost all concave surfaces. The rubber drums will give you the flexibility for curved surfaces and different barrel sizes will make it fit for parts of any size.

Sanding with a Drum Sander – In the Below Image:

Smooth sanding with drum sander
28pk Sanding Drums and Sleeves Set for Drill: Check on Amazon=>

d) Using Sponges:

sand concave surfaces wood with sponges sander
3M Sanding Sponge: Check More=>

Another great and cheap solution for sanding concave surfaces is using sponges. You can glue sandpaper with a piece of sponge and wrap around a cylindrical wooden or metal piece. This will let you sand some specific and small pieces where other solutions can’t reach easily. Sanding wooden toys with this sponge method help to achieve smoothness without destroying the look.

Any Curve

We’ve seen some great tools and methods for sanding convex surfaces as well as concave ones. But 2 tools will help you sand any curved surfaces. After some research, we have found 2 great tools that you already might know of.

flap sander to sand any irregular surface
Flap Sanding Tool=> Check on Amazon>

Flap Sanders is our most recommended sander to sand any irregular surface. These are soft-headed sanders with abrasive strips. Flap sanders should be a top priority to sand without destroying the detail of the profile reaching hard-to-reach places. You will find different shapes and sizes that’ll fit your flap sander.

Lathe Sander to sand curved wood surfaces
Sanding with Lathe Sander > Check on Amazon

Lathe Sander is the last tool that we recommend for regular curved surfaces. For other tools, the sander moves and the piece stays stationary. But here the piece spins and you the sander stay still. This type of setup ensures even sanding and a very smooth finish. The wooden piece that you can attach to the lathe is fit for this tool.


So, you understand that you can’t go with one simple solution. For different types of projects, you’ll have to use different tools and methods. However, we liked the performance of the flap sanders. With other tools, you’ll be able to remove materials quickly and stop for the final smoothness. You can rely on flap sander for the finishing touch.

Last Updated on July 20, 2020 by Rogers Weber

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