How to Clean a Sharpening Stone


how to clean a sharpening stone

Sharpening stones are the most popular and oldest way to sharpen knives and tools. With their versatility, they can be used to sharpen almost any edge. But, with time, metal fillings, oil and dirt can embed in the stones, making them less effective. To ensure your sharpening stone doesn’t get clogged and that it always works well, you need to clean it regularly. Follow this easy DIY guide to learn how to clean a clogged sharpening stone effectively.

How to Tell if a Sharpening Stone is Oil or Water

Besides diamond stones, oil stones and water stones are the two common types of sharpening stones. Here, we are going to focus on oil and water stones to help differentiate between the two.

Oil Stones

These stones are made from Novaculite, Aluminum Oxide or Silicon Carbide, and use oil for swarf removal.  They have the slowest cutting rate as compare to the other main types of stone. Most traditional oil stones are natural stones made from Novaculite, they are separated into different grades depending on the density and finish a stone produces on a blade. They are quarried in Arkansas hence the name Arkansas stones. These natural stones can produce a polished edge, but tend to cut more slowly than man-made ones.

Aluminum Oxide oil stones are a very popular man-made choice, with the India stone being the most popular. They can cut fast, and also produce fine edges on knives and tools. These stones are typically brown or orange in color. They are also coarser than Arkansas stones.

The oil stones made of Silicon Carbide are the fastest when it comes to cutting. They are usually gray in color. However, they don’t produce an edge as fine as natural or India stones.

Water Stones

The water stones, like the oil stones, are available in both natural and synthetic materials. Generally, synthetic water stones are made of Aluminum Oxide, just like the India stones. The difference between the two is the binder holding the abrasives together. Water stones are softer than India stones and tend to wear down more quickly. Also, water stones use water rather than oil to remove swarf from the stone.

Different Ways to Clean a Sharpening Stone

Things you may need:

  • Honing oil
  • Soft toothbrush
  • WD-40
  • Flattening plate
  • Sandpaper( 400 and 100-grit)
  • Piece of cloth

There are several methods to clean your sharpening stone. You can use honing oil to flush out mineral filings. Honing oil is a mineral oil that is often used in machine shops to carry away metal debris from stone.

  • Use your finger or a soft toothbrush to rub a quarter-size amount of honing oil onto your stone. Rub in small, circular motions until metal flecks rise up from the stone’s pores.
  • Use a damp cloth to wipe away the metal flecks from the surface of the stone.
  • Then, rinse the stone thoroughly under running water to remove any remaining metal debris and then dry it.

Can I Use WD40 on My Sharpening Stone?

You can also use WD-40 to remove the dirt and grime on your stone. WD-40 has the ability to penetrate tough surfaces. To clean your sharpening stone using WD-40;

  • Spray a coat of WD-40 on the surface of your stone until it is entirely coated.
  • Then, use an abrasive tool like steel wool to scour the surface of the stone gently to remove the grime.
  • When the oil and debris start to come off, use a damp cloth to wipe the dirt, oil and WD-40 off the stone.
  • Repeat the process until no dirt or grease remains on your stone.

Flattening Your Sharpening Stone

Flattening your stone avoids it dishing out and helps remove embedded metal filings. While some sharpening stones may come with their own flattening plates, others may not.

  • Rub the sharpening stone over a flattening plate to remove embedded metal filings.
  • If you don’t have a flattening plate, you can sand away metal filings using a piece of 100-grit wet-dry sandpaper.
  • Then, run a piece of 400-grit sandpaper firmly over the stone to remove any large scratches that may collect debris.
  • Flatten your stone after 10 sharpening sessions, or more often, to stop it from hollowing out in the middle.

Do You Have to Wet a Sharpening Stone Before Use?

While sharpening stones can be used dry or wet, the latter is recommended. Water, water-based honing oil, or petroleum-based honing oil helps keep the stone’s pores clean. They also help in dissipating the heat that arise from the friction and ensures smooth sharpening action.

Knowing what to use when cleaning sharpening stones is the key to getting the best results. While honing oil can help remove the metal fillings in your stone, to get rid of dirt and grime, you’ll need to spray a coat of WD-40. For stubborn debris or caked oil, you need to use steel wool or any abrasive tool.

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