What Does Sanding Polymer Clay Do And Do I Need To Do It?


Many people don’t bother sanding polymer clay as often the surface of the clay is smooth enough. This is especially true when working with miniatures as the surface area is so small.

But, if you’ve baked your clay and noticed some imperfections on the surface, sanding it is the best way to get a super smooth finish.

Sanding polymer clay removes fingerprints, dents and scratches on the clay to create a super smooth finish on the clay’s surface. While you don’t need to sand polymer clay, it will remove any annoying imperfections once your clay has been baked.

Below, we take a closer look at how to sand polymer clay and what the benefits of sanding are.

What do you sand polymer clay with?

You can buy sanding sponges specifically for polymer clay but these tend to be more expensive than regular sandpaper. Sanding sponges are available in rough, medium and fine grades.

The best sandpaper for using with polymer clay is silicon carbide wet and dry sandpaper as it has a sharper and harder grain than sandpaper coated with aluminium oxide. You’ll need sandpaper that can be made wet as you’ll be sanding your polymer clay model under water (more on that later!).

As an alternative to sandpaper, you could try using micro mesh pads which are cushioned abrasive pads that come in a wider range of grit sizes compared to sand. These do tend to be pricier than sandpaper though and you can’t use them underwater. But they are a good option if you struggle to hold your polymer clay and sandpaper at the same time, as these mesh pads can be laid on a surface so you can work your model over the surface of the pad.

What type of sandpaper do you need for polymer clay?

You’ll need three grades or ‘grits’ of sandpaper. The grit refers to how big the abrasive material on the sandpaper is. Sandpapers with a higher grit number have abrasive materials on them that are finer than sandpapers with a lower grit number. Sandpapers with lower grit numbers scrape off surfaces much quicker, but they don’t leave as smooth a finish as higher grit sandpapers.

When working with polymer clay, you’ll need the following sandpaper, listed below from coarsest to finest:

  • 320 grit sandpaper
  • 600 grit sandpaper
  • 1200 grit sandpaper

You’ll start with the roughest paper and work your way to the finest grit so that your clay becomes smoother as you work your way through the different types of sandpaper.

Sandpaper is usually sold in A4 sheets but you can easily cut the sheets down to size to make them more manageable to use. Just make sure you label what grit they are on the back for future reference.

Why do you sand polymer clay underwater?

It’s best to sand your polymer clay underwater – the water will collect the dust that accumulates as you sand your clay. This not only prevents the dust from circulating in the air which you could potentially breath in, it also prevents it from sticking to your polymer clay.

Bear in mind though that polymer clay is made of plastic and small particles of it can be potentially dangerous to marine life. Instead of sanding your model in the sink, do it in a container of water instead, this way you can soak up the water and polymer clay dust with paper towels when you’ve finished and throw them in the bin.

Fill your container with lukewarm water – if the water is too cold it will make the polymer clay hard, if it’s too hot it will soften the polymer clay too much.

Sanding underwater will also prevent the sandpaper from getting clogged up with polymer clay dust as you can rinse any build up or clay dust off in the water.

3 steps to successful polymer clay sanding

Step 1 – 320 grit sandpaper

You’ll need to start with the 320 grit sandpaper as this is course enough to remove any blemishes to the surface of the clay, such as fingerprints. You can also use this denser grit sandpaper to reshape your clay if you need to.

If you find you have a larger area you want to reshape, then you could choose an even lower grit sandpaper to make this step a bit quicker such as a 220 grit.

Step 2 – 600 grit sandpaper

Once you’ve removed all the obvious surface markings or reshaped your polymer clay, you can then move onto your next level of sandpaper. Using 600 grit sandpaper will remove any scratches made during the first sanding step and will begin to give your polymer clay a super smooth surface.

Step 3 – 1200 grit sandpaper

The final step is to use the finest sandpaper (1200 grit) to really smooth out any remaining blemishes on the surface of the polymer clay. It’s best to dry the clay with a towel or kitchen paper to see how smooth the surface is.

Further Questions

Can you sand polymer clay with Dremel?

A Dremel looks like a drill but has a variety of attachments that can be used for a range of craft projects, from sanding and buffing to carving and even engraving. A Dremel can be used to sand polymer clay if you need to significantly reshape the clay, but Dremels are powerful so it’s easy to make a mistake and ruin your model. If you want to use a Dremel, it will make sanding quicker, but it’s best to do a few practise runs on scrap clay so you can perfect your technique before using it on your model.

Do you need to wear a mask when sanding polymer clay?

If you’re sanding your polymer clay underwater then you won’t need to wear a mask. If you’re sanding polymer clay out of water then you’ll need to wear a dust mask.

Do you need to sand polymer clay?

No, you don’t have to sand polymer clay. Baked polymer clay usually has a pretty smooth finish anyway but sanding is a good idea if your polymer clay has dents, fingerprints or other blemishes on the surface. If you’re making miniature models out of polymer clay then you might find that models which need a smooth surface, such as crockery, might benefit from being sanded.

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