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Silicon carbide sanding paper gives sharpening stone metal glancing

Flattened a Chinese sharpening stone 220#( very hard) first with Naniwa flattening stone and the wet/dry silicon carbide sanding paper 80#.

After the silicon carbide paper I noticed that the peaks on the surface got glanced and covered
with a metal glancing look. Need to look sidewise in low angle to see this.
It has not filled the "valleys".

Don't really see anything when looking with a usb-microscope straight above but with a loupe looking side vise or just direct visual looking in low angle.

Anyone recognize this?
 
I don't understand the word glancing in this context.

I once flattened a SiC stone with coarse W/D and it took all the cutting ability from the stone until I re worked the surface with loose grit SiC. It was like the W/D rounded all the cutting edges of the exposed particles of the stone.
 
I don't understand the word glancing in this context.

I once flattened a SiC stone with coarse W/D and it took all the cutting ability from the stone until I re worked the surface with loose grit SiC. It was like the W/D rounded all the cutting edges of the exposed particles of the stone.

Glancing is perhaps not what I meant to describe, sorry.
Smoothed out.

Visual look in low angle seeing what looks like spots of metal loading.

Looking with loupe in low angle seeing the individual top being leveled flat and covered with something dark metal looking. Not giving the impression of being effective for metal scratching.


Sounds like the sandpaper and the stone are similar in hardness. Not sure though. I would use diamond to dress the stone and expose fresh grit and see what happens.
I went back using the Naniwa flattening stone and it seems to turn it right.
 
When flattening most any hone or stone you are glazing it - flattening or rounding the peaks of the abrasive particles contained in the stone/hone. For most this is not a problem, as they either shed the dulled particles pretty rapidly or the initial intention was to make the hone or stone cut finer anyway. For coarser stuff I far prefer a quick loose grit lap after flattening with a diamond plate or wet/dry to "wake up" the surface a little.
 
Glancing is perhaps not what I meant to describe, sorry.
Smoothed out.

Visual look in low angle seeing what looks like spots of metal loading.

Looking with loupe in low angle seeing the individual top being leveled flat and covered with something dark metal looking. Not giving the impression of being effective for metal scratching.



I went back using the Naniwa flattening stone and it seems to turn it right.
I've had arkansas and a thuringian that had random particles that looked like bigger particles of silicone oxide or quartz. The arks I've lapped with everything, but it's a stone with properties similar to granite in that they're were random, big particles of quartz spread about.
 
Yep.
SIC can embed in stones. When using 3M w/d, I don't run into an issue there but if I use the cheap stuff from the hardware store I see it pretty often.
Loose SIC can/will do the same, which is why I'm not a fan of using the stuff on synth water stones like Super Stones, Chosera, etc. It can be OK on some of the much harder ceramic types but if the stone is very porous then the possibility of SIC getting 'in' arises. It can still mash into the surface easily on those stones that are prone to glazing.
I never use w/d coarser than 220. If I need to remove a lot of material from a stone I use a 140x diamond plate. I find w/d under 220x to be not so very useful.
 
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