Flattening whetstone: mine seems clogged now?

J

JeffOYB

Joined
Apr 22, 2004
Messages
33
I have a common whetstone. I don't know what it is, though. It's about 1"x3"x10". It's artificial. Dark grey color. Has coarse and fine sides. I've used it for 30 years.

It got a belly in the middle third so I thought I'd finally flatten it. I'd read that you can put sandpaper on glass to do this. So I bought a bunch of 80 grit paper and went to town. It's not totally flat yet but after 2 hrs of elbowgrease the belly is smaller.

I misted it w red spraypaint so I could check flatness. I also sprayed the paper w WD40 as I went along -- a kind of lube.

The ends of the stone that are getting flat are now grayer in color and smoother to feel.

I tried sharpening with it just now and there is no "bite" on the coarse side. The center section which isn't flat yet and is light pink does have the nice old grit feel. I used hot soapy water and scrubbed the stone. Then I used a metal brillo-pad. No change. The stone no longer functions.

Any ideas for recovering it from my crimes? Maybe some kind of gas or PB Blaster solvent to soak it...

The sheets of paper have been wearing out as I tried to flatten the stone. I don't know what is getting into the stone to clog it up or wreck it. Help?
 
Try loose abrasive with a little water and dish soap, it will work worlds better than sandpaper. The soap will help cut the oil and crap that has soaked into your stone, and it will be hard on your flat. If nothing else sand will work but black silicon carbide would probably be the best, personally from what it sounds like you want sand would be my pick.
 
After 30 years might be time to get a new one... or upgrade to diamond hones, which should be good for the next 30 years.
 
What you have is most likely a silicon carbide stone.
I'm guessing that over the course of two hours the sandpaper itself got finer, which made the stone finer.
If you don't have coarse grit and float glass, try again with fresh sandpaper and stop after a few minutes. Then try using it.
 
J JeffOYB When you say it's clogged up do you mean with metal filings from sharpening that we often refer to as swarf on the forum,if so try getting some Bar Keepers Friend powder in the gold canister don't get the liquid or the powder in the silver canister that say's it's for stainless steel.

Many people on this forum use Bar Keepers Friend in the gold canister and it's in the same packaging as Comet,it won't matter how long the swarf has been sitting in your stone it will get it out and it will do it extremely fast and easily.

When I'm done using a Venev resin bonded diamond stone or any for that matter whether it's a sic or aluminum oxide stone it blast's right out,I have tried using stiff plastic bristle brush's and everything else you can think of and really scrubbed hard and not mad any of it budge but with Bar Keepers Friend just sprinkle a bit on the stone and scrub with your hand,whatever it does is like an instant reaction and after 5 to 8 seconds of scrubbing I can rinse my stones and they are clean but you may need to scrub a bit longer.

BFK also works great on stainless steel pots and pans,if you use it on anything that can rust be sure to dry it off right away and then spray it with cooking spray or use some cooking oil and wipe it down and then wipe off the excess and it will be fine.
 
If nothing else try dressing it with the loose grit on a flattish surface. Even a spot of concrete that you won't mind wearing down a little would work, your lapping surface doesn't need to be perfectly flat. You want to get the loose grit rolling around between your stone and the lapping surface. The only other thing that would work is a coarse diamond plate, sandpaper is not even in the running.
 
Thanks everybody! I tried the sand water soap on glass idea and it seemed to clean the pores of my stone. Whew!

So will this be a good way to flatten the stone? I like that concrete idea, too!

The sand had varying grain sizes at first but seemed to make a slurry and the bigger pebbles got pushed away. Interesting!

Now I have another problem. Maybe worse! I've tried sharpening 2 knives and haven't been able to raise a burr! What the heck? I've been sharpening for decades and can raise a burr on anything. I could take any knife and raise a burr on a brick. I mean, it's never been an issue. Happens quickly. I've now been trying with these knives for much longer than usual and no burr! Maybe my mind is going. Or my hand angle control. I've been able to sharpen any size knife to razor sharp quickly for decades. Pop arm hairs. It's not happening now. I've gotten burrs on these 2 knives a couple months ago. ...Before my flattening project. Hmmm... It's kinda nuts. I have been under stress... Very strange.
 
The concrete idea is to save your glass from the wear and tear, for a coarse stone your flat doesn't have to be terribly flat to work. Also, you don't want a shiny surface, you don't want the sand to slide around. You want it to roll between the stone and flat for best performance. This is a great way to flatten your stone, the other way is a coarse diamond plate. Other than a surface grinder with a diamond wheel there is no other way to flatten a stone IMO. I think the water content in the slurry is very important. Too much and it washes away, too little and it clumps up and doesn't do much. Just right and it rolls around and you can really feel it doing its job.

Are you getting your knives sharp and just not getting a burr? Perhaps now that your stone is sharp it is removing the metal vs pushing it off the edge forming the big burr.
 
Hi... Thanks for the thoughts. I'll keep playing w my slurry. I want a flat stone, both sides. About the sharpness: no, they're not sharp. Won't shave arm hair like used to easily. Neither coarse nor fine side raises a burr now. Very odd. I'll keep trying.
 
I tried using some other whetstones I had around. I have a little Spyderco coarse stone -- 1"x5"x.25"; a DMT about the same size; a Hard Arkansas. I was able to quickly get a burr using any of these. Shaved arm hair decently. Whew!

My project to flatten my sweet old stone has failed. I'll see if i can find "coarse loose grit" at the hardware and will try that. Also Barkeep's Friend.
 
Perhaps you need a harder abrasive, like black silicon carbide, to dress your stone with. Black is the least friable so that is why I specify. You say yours is dark grey so that leads me to believe it is silicon carbide, so softer abrasives are not conditioning it like they should. Just a thought.
 
I've had pretty good results using rock polishing media on glass. Just try to match the grit with the stone. If not exactly as coarse as desired, simply sprinkle on larger grit until you get results wanted.
 
JeffOYB said:
...I'll see if i can find "coarse loose grit" at the hardware and will try that...
Click to expand...
Hobby Lobby (and I assume Michaels) has $5 "grit-packs" for rock tumblers, including coarse medium and fine grits. (And if you have a hard time finding Bartender's Friend, Gritomatic has it.)
 
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