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How To Sand Curved Surface?- Sanding Convex/ Concave Surfaces

Before moving to ‘how to sand curved surface?’, it is important to know why it requires special attention to sand a curved surface. Curved surfaces can be in two different forms- concave and convex. A concave surface is bent inwards to the wood, whereas a convex surface is curved outwards. Though it seems a bit tricky to sand such curves, with the right tool you can do the job without struggling. Now let’s jump into our main topic!

Sanding convex or concave surfaces can really be a big issue if you don’t know how to do it or if you’re doing it for the first time. It’s totally different from sanding a plain surface. You need to be really careful about a few matters and also need to follow a certain sanding pattern. Though it’s not a hard task, you can easily ruin the wood with the slightest bit of distraction.

How to Sand Convex/ Concave Surface

You can use a power tool if the project is big but hand sand it when the task is little. Before you start to sand, make sure the cut is clean and even. To smooth a convex curve use a flat-soled spokeshave and for a concave curve use a curved-sole spokeshave. The trick here is to use the tools in the direction of the grain.

To sand a curve you can follow any of the two processes- using an angle grinder or a hand sanding tool.

Sanding Using an Angle Grinder

Sanding Using an Angle Grinder

This amazing tool is very useful for bulk sand and to give the wood piece a shape. It is also useful to sand a large curved piece of wood. It only requires attaching abrasive pads to the grinder’s head to sand away the uneven surface.

So, unplug the machine and attach the abrasive pad with the grinder. Then turn on the machine and start sanding. Don’t hold the machine in a place for long. Keep it moving against the grains. Keep sanding until you finish the whole piece of wood. This will result in a polished surface and would remove any abrasive grain of the wood from the top. This thing will get most of the job done.

Turn off the main socket or the tool if it’s battery-powered whenever you change the disc. Then take the 120-grit flap sanding disc and secure it to the machine. Give light strokes and don’t push hard against the grain. Otherwise, you’ll ruin the wood. Look for any uneven surface to smoothen it out. Thus you get a curved surface polished with an angle grinder.

However, you can use an orbital or random orbital sander for a smoother finish.

Hand Sanding with a Handmade Tool

Whether you’ve used a power sander or other sanding tool, occasionally you need to hand sand curved surfaces. Also, sometimes the last finish requires a touch of the hand. So, here we are giving you a simple solution and will make a hand sanding tool.

Woodworking essentials-

  • Sandpaper grit of your choice (8 to 10 in long)
  • Paint stick
  • PVC pipe
  • Adhesive
  • A utility knife

Take the piece of sandpaper and spread the adhesive on the back. Using a sprayer is the easiest way to spread adhesives, but you can also do it manually.

Then pick the paint stick and jab it in the adhesive. Trim from the border with the utility knife. And repeat the process with PVC pipe.

Now you have two handmade sanding tools to sand off the curves. The paint stick is for the outside curves or the convex surfaces. And the round one that is the PVC pipe is useful for the convex or inside curves.

Take the tool you need and simply sand away any roughness from the wood surface.


*Do not misplace the tools or use them inversely. You may end up flattening the curve.

*As the PVC pipe comes in many shapes, you can easily pick any diameter that’s compatible with your project.

Safety precautions!

*Wear appropriate outfits when your woodwork. We recommend wearing a full sleeve shirt and heavy pants. And wear other personal protective equipment including-

  • Protective goggles or face shield
  • Respirators
  • Earmuff or hearing protection
  • Hand gloves

However, most woodworkers go as they are, possibly because of their expertise and everything. It’s better to take precautions when doing sanding jobs. Safety gears prevent wood dust build up in your lungs or any sudden wood spit from entering the eyes or other sensitive body parts.


We hope this article helped you with sanding both curved surfaces- concave and convex. Do not forget to wear protective gear when sanding to avoid any unplanned occurrence.

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