Spyderco Forums

I have been looking around for a new flattening technique for my whetstones and I was hoping to pick the brains of anyone who has used any of the various methods I'm considering.

The first method is adhesive backed sandpaper on glass. I have used Wet or Dry sandpaper before, but the issue is that it isn't stuck to the surface by anything other than suction, which I get by wetting the back a little. That doesn't work brilliantly so I thought that adhesive backed paper might be a solution. I'm not sure how much extra you pay for adhesive backed, or where to get it exactly though.

The second idea is to use a spray adhesive to stick some sort of sandpaper to glass. So same basic idea, just manually applying adhesive in this case.

The third method I am most unfamiliar with and sounds messier, silicone carbide powder on glass. The article I read said, "Use silicon carbide grit on a sheet of glass covered by a protective layer of laminate to prevent the glass from becoming dished." I have no idea what "a protective layer of laminate" is though. Anyone know what this refers too? As I mentioned above, this sounds a little messy to me, but I suppose it might not be that different than the other methods in the end. I am wondering though, when you do this, do you rinse everything off every time, then apply more powder every time you flatten?

Any feedback is much appreciated.

Glass with a plastic protective film, like the stuff they put on new appliances (the "Remove Before Using" stuff). That way the silicone carbide grit sticks in the plastic instead of grinding away the glass, at least in theory.

I've flattened a few whetstones and dressed some resin bonded diamond stones with SiC and a glass plate. I just put the SiC directly on the plate with some water, no protective layer. Haven't noticed any dishing after doing 4-5 stones so far. Easy enough to get another glass plate if it gets dished out is the way I see it. I found that I needed to add water periodically. If I'm switching to a different grit SiC, I'll clean off the old grit/particles first, then start again. Also, buying rock tumbling SiC powder was cheaper than getting stuff advertised specifically for whetstone flattening and worked just fine.

Whenever i condition or flatten my waterstones i keep everything inside a large plastic tupperwear container. My go to is a rectangular version found in hardware stores for spackling but use whats available. And i use a different level system depending on what im trying to do. Barkeepers friend or a nagura for general cleaning. For conditioning i use the fine side of sic axe puck. Thats after i soak the stone a little longer than recommended to make the binder a little weaker to help shed easier. Then i have the option to use the coarse side of the puck or a combo of the puck with sic powder usually 60/90 for more aggressive removal. All powder is contained, so i can run the leftover slurry thru a coffee filter and seperate the sic powder from hitting the drain when done. Or if i need to use more than 1 cycle. Usually the fine side of a silicon carbide axe puck is around 220-280 grit, and the coarse side is around 120 but shop around. I think the lansky silicon carbide pucks are around 10 bucks currently.

I will use double sided tape to stick sand paper to a glass plate with good results.

I also use the below diamond flattening stone. It’s cheap and “junk” but it actually works surprisingly well. I have used it on my King stones from 300 to 6000 with good results on my hand planes.

https://www.amazon.com/gp/aw/d/B07H4T6S ... asin_title

Thanks for the info so far folks.

WilliamMunny wrote: ↑

Thu Apr 18, 2024 6:54 pm

I will use double sided tape to stick sand paper to a glass plate with good results.

This sounds like a good idea to me, I'll probably try this out.

Uneducated question (I have almost no experience with wetstones):

Why do you all appearantly use specifically a glass plate to stick sandpaper or whatever abrasive to?
Why not any other hard plate? (Like some metal)?
Is it because glass has the least tendency to bend or something like this? (A thicker metal plate would not bend either, right)?

Wartstein wrote: ↑

Sat Apr 20, 2024 11:26 pm

Why do you all appearantly use specifically a glass plate to stick sandpaper or whatever abrasive to?
Why not any other hard plate? (Like some metal)?

Glass is cheap. Glass is flat enough. Glass wears slowly enough.
I have an old cast iron surface plate. It's not super-precise, but I'd prefer to keep abrasives away from it nevertheless. Granite is another great material for surface plates. But they're expensive, and we don't need that level of precision for sharpening knives. We're not building Space Shuttles here.

RustyIron wrote: ↑

Sun Apr 21, 2024 12:11 am

Wartstein wrote: ↑

Sat Apr 20, 2024 11:26 pm

Glass is cheap. Glass is flat enough. Glass wears slowly enough.
I have an old cast iron surface plate. It's not super-precise, but I'd prefer to keep abrasives away from it nevertheless. Granite is another great material for surface plates. But they're expensive, and we don't need that level of precision for sharpening knives. We're not building Space Shuttles here.

Thanks, Rusty! Makes sense.

The stones that live in the garage are not well cared for. They're not for knives, they're for cutting tools or whatever I might be working on. They get pulled off the shelf when needed. They're generally slopped with cutting oil. If they get gummed up, they get put back and another stone is pulled off the shelf. It's rare when they get any attention. Well, today was that day. They got flattened and cleaned up a bit.

My neck is now sore, my fingertips tender, and my hands smell like sulfur. But the stones are all pretty now and ready for action.

RustyIron wrote: ↑

Sun Apr 21, 2024 12:11 am

Wartstein wrote: ↑

Sat Apr 20, 2024 11:26 pm

Why do you all appearantly use specifically a glass plate to stick sandpaper or whatever abrasive to?
Why not any other hard plate? (Like some metal)?

Glass is cheap. Glass is flat enough. Glass wears slowly enough.
I have an old cast iron surface plate. It's not super-precise, but I'd prefer to keep abrasives away from it nevertheless. Granite is another great material for surface plates. But they're expensive, and we don't need that level of precision for sharpening knives. We're not building Space Shuttles here.

I have a machinist's granite surface plate but don't use it for flattening because it's a precision item and I don't want it to wear. As Rusty says, a glass plate is pretty durned flat, works well, and if it starts to dish, just toss it for another. I cut up an old mirror decades ago into 10x12 pieces, and that's enough for a lifetime of silicone carbide flattening...for free.

This is what I'd recommend buying from Lee Valley with some loose abrasive if you go that route. It may help to know what make/model of stones you are planning to flatten also. Waterstones, oilstones, Spyderco ceramics, etc...

https://www.leevalley.com/en-us/shop/to ... em=05M2012

https://www.leevalley.com/en-us/shop/to ... em=05M2011

I'm not personally using this method but it works well and is inexpensive if you can find cheap loose grit. Just make sure to wet the loose grit a bit prior to using so you're not risking inhaling any of it.

Traditional.Sharpening wrote: ↑

Fri Apr 26, 2024 4:34 am

This is what I'd recommend buying from Lee Valley with some loose abrasive if you go that route. It may help to know what make/model of stones you are planning to flatten also. Waterstones, oilstones, Spyderco ceramics, etc...

https://www.leevalley.com/en-us/shop/to ... em=05M2012

https://www.leevalley.com/en-us/shop/to ... em=05M2011

I'm not personally using this method but it works well and is inexpensive if you can find cheap loose grit. Just make sure to wet the loose grit a bit prior to using so you're not risking inhaling any of it.

I have two water stones, a Cerax soaking stone and a Naniwa splash and go.

I am assuming these laminate sheets wear out eventually? Any idea how long they tend to last?

Also, does anyone have a suggestion for where to get silicone carbide grit for cheap?

At this point I might just try sandpaper and loose grit and see if I like one more than the other, or just use whatever I end up getting my hands on first.

Scandi Grind wrote: ↑

Tue Apr 30, 2024 7:09 pm

Traditional.Sharpening wrote: ↑

Fri Apr 26, 2024 4:34 am

This is what I'd recommend buying from Lee Valley with some loose abrasive if you go that route. It may help to know what make/model of stones you are planning to flatten also. Waterstones, oilstones, Spyderco ceramics, etc...

https://www.leevalley.com/en-us/shop/to ... em=05M2012

https://www.leevalley.com/en-us/shop/to ... em=05M2011

I'm not personally using this method but it works well and is inexpensive if you can find cheap loose grit. Just make sure to wet the loose grit a bit prior to using so you're not risking inhaling any of it.

I have two water stones, a Cerax soaking stone and a Naniwa splash and go.

I am assuming these laminate sheets wear out eventually? Any idea how long they tend to last?

Also, does anyone have a suggestion for where to get silicone carbide grit for cheap?

At this point I might just try sandpaper and loose grit and see if I like one more than the other, or just use whatever I end up getting my hands on first.

They will wear out eventually but I'd say that depends on many factors ultimately. Type of loose grit, pressure applied, stone shape/size/wear, etc. all would come into play here. This should also keep the loose grit from rolling as much to increase cutting efficiency as well.

Quality loose grit here : https://www.sharpeningsupplies.com/Nani ... 07C97.aspx

Sandpaper is probably least preferable method, IMO. It may affect the way the stone behaves/cuts.

Sent you PM with some other info...

Scandi Grind wrote: ↑

Tue Apr 30, 2024 7:09 pm

Also, does anyone have a suggestion for where to get silicone carbide grit for cheap?

I've bought from this company before, they are the cheapest I've found:
https://hplapidary.com/collections/ungraded-grit
https://hplapidary.com/collections/graded-grit

ekastanis wrote: ↑

Wed May 01, 2024 1:06 pm

Scandi Grind wrote: ↑

Tue Apr 30, 2024 7:09 pm

Also, does anyone have a suggestion for where to get silicone carbide grit for cheap?

I've bought from this company before, they are the cheapest I've found:
https://hplapidary.com/collections/ungraded-grit
https://hplapidary.com/collections/graded-grit

Good prices, thanks for the source!

Not an advertisement!)
https://dzen.ru/video/watch/6409c5bec7e ... 5ddd?f=d2dhere is a video on how to align grindstones.applicable to all materials-diamonds, silicon carbide, elbors, aluminum oxide (Boride)
https://tsprof.ru/upload/iblock/f85/ekw ... mg_47_.png in this link, the table shows which grain size of silicon carbide to use for grinding stones according to their grain number