Synthetic whetstones / water stones (man-made) make-up the bulk of all sharpening stones available today. There was a time decades ago when natural stones (from the earth) were the only available option for keeping your knives, razors and tools sharp and ready for use. Many people remember their grandparents sharpening kitchen knives on a large rock on the bench. Times have changed, and now there is a huge selection of synthetic stones to help you with all facets of sharpening. From initial bevel setting to final mirror polishing, there is a stone for you.
However, don’t assume because the synthetic market is larger than the natural stone market, they are always better – that is not so! Natural stones can be just as effective in producing a sharp edge. Like all tools, it comes down to your personal preference, more so than the product.
One benefit of synthetic stones is the easy to follow grit ratings. Unlike naturals, synthetic stones come with a set grit rating on each and every stone. Of course, different brands using the same grit are not guaranteed to be actually equal! The lower end of the scale (less than 1000 grit) is for general sharpening tasks; where’ as grit numbers in the 5000+ are used in the final stages of sharpening and beginning stages of gaining a polished edge. Depending on your intended tasks for your knives or tools, will also dictate how high (refined) you need to go.
Synthetic stones are also consistent. What is that? Consistency means that every time you sharpen on a specific whetstone / water stone (let’s say 5000 grit), you will get a similar result each and every time (from that same grit / brand and your technique holding true of course). This can be slightly different to natural stones, where the finish can sometimes alter from stone to stone.
Which stone to use?
If you have decided on synthetic stones for your sharpening needs, then how sharp your knife or tools initially are, will dictate how low a grit you need to start at. If you try to sharpen a blunt knife on a high grit stone (5000+), although it can be done, it will take some considerable time. The idea with sharpening in an ideal situation is to do minimal amounts of sharpening on each stone – moving up to the finer grits each stage slowly (the course levels are used to remove the most steel > quickly, while for refining you move up the scale).
If you are looking for a sharp edge for utility tasks (this is where most pocket knives land), up to 5000 grit is usually more than enough for this purpose. The higher the grit, the more polish and less steel removal.
When selecting a progression / combination, one easy method (although not set in stone by any means), is to ‘double’ your grits. For example:
500 – 1000 – 2000 – 4000 – 8000
Like natural stones, synthetic stones require the same ingredients to success:
- And lastly – never blame the stone > 99% of the time, it is the technique.
Keep in mind synthetic whet/water stones will need to be lapped (flattened) on a regular basis to ensure they stay – flat! If they are not lapped, they can develop a convex ‘dip’ in the stone called dishing. The larger this dishing becomes, the longer it takes to flatten the stone.
Always read the directions on the packaging regarding the length of time needed to soak your ‘specific’ stone before use. However, most synthetic stones are simply wet and work; or in some cases (unless otherwise stated) a 5-10 minute soak is all that is required before you can begin (remember to also keep the stone wet throughout the sharpening process also). Unless stated, never leave them soaking in water for too long, as the water in some instances can begin to break down the binder that holds the brick together, making soft and later crumble.
By the way, a whetstone actually translates to sharpening stone – not wet (water) stone – although you of course can use water.