How To Very Old Wet Stone ('40s) how to resurface?

A

At1Rest

Joined
Apr 11, 2019
Messages
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Hi there,

I got interested in this forum and resurfacing my Grandfather's to Dad's old whetstone (oil?) stone a bit after I discovered an old Case xx Sodbuster 3138 in the bottom of tin coffee can under a bunch of rusty nails.

The blade was covered with rust. I used sandpaper 120, 220, 320, 400 to remove the rust.
It wasn't really sharp when I found it but I wasn't aware enough to know to avoid ruining the profile, or even if it was worth saving.

Anyway, I got the Sodbuster cleaned up and then started (cluelessly) sharpening on the old whetstone that I'm asking about.

It got sharp enough to cut paper,

but it's not quite as sharp and smooth with the paper cutting as 2 (never used) Swiss Army Knives, my new Leatherman Wave+ blades and one ancient straight razor that I'm sure I (cluelessly) sharpened on this same dished and scratched up whetstone.

I've watched a few YouTube videos about resurfacing stones but I'm not convinced that's the way to go with this one as it appears to be a fine grit.

Based on my limited experience with polishing papers, and particularly comparing it to some new Norton Emery Paper (very fine A621 3/0 609) which I believe is about 1000 Grit, my fingertips are guessing this stone was originally 1000 grit or finer.
(see some photos (some macro) here: https://photos.app.goo.gl/bTTUtvv9MaBepQi87

So, I don't want to degrade the grit on the stone by using pavement in the drive way, my belt sander with a 120 Grit belt, or the wet/dry paper on glass route, without getting some expert advice first.

My 'guess' is that if I use an coarser abrasive on the stone, the stone will then inherit the same grit as that abrasive?
Not sure ... don't know.

Will I have to refine the surface back to where it 'should be' by working my way up form very coarse to very fine?
Or,
Will the stone eventually just find it's way back to what it really is just by using it?

All thoughts and comments are very welcome.
Last week I had no idea what a dished stone was, or what apex and burr really meant when it comes to sharpening.

I'm into the details and learning so if you will, please, talk with me about resurfacing this stone, and anything else that comes to mind.

Thank you!

Oh ... It's been used with oil most of the time, but sometimes way back in the 70's and 80's I'd just spit on it ... but does it have to be used with only oil?
Is there a way to clean it so that it can be used with maybe water alone, or water and some dish washing liquid?
 
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Is there any molded in lettering on the stone on the edge or the back ?
I am a little concerned that it could be a razor stone. You don't want to try to condition a razor stone.
See the third photo at this LINK > > >
 
Hey Wowbagger,

No, there is no lettering or branding on the stone at all.

"razor stone" ... humm ... might be. My granddad used a cutthroat razor,
but I vaguely remember my dad sharpening plane blades and wood chizzles on this stone back in the '50s.
He never told me any details other than showing me how he put oil on it.

What about trying something on one of the short sides to see what happens?
Maybe we can figure out what it really is by seeing how it reacts to some testing?
 
At1Rest said:
Dad's old wet (oil) stone
Click to expand...

Pardon my pedanticism but I believe you mean whetstone. Water stones and oil stones are types of whetstones. It's a common mistake due to the wine–whine merger.

I haven't used a stone like yours so I hesitated to comment further, but Stefan Wolf on YouTube (stefanwolf88) flattens and conditions all sorts of stones; perhaps contact him or try his method?

 
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Ahhh ... thank you Mr. Wizard. Whetstone. I'll remember that now.
I'll also have a look at the Stefan Wolf video later today and see if I can contact him.
 
At1Rest, welcome. Your stone looks like a black Arkansas and the method shown in the video Wizard posted will work. I would Never do that in the house as my wife would throw me in a head lock and teach me what not to do in her kitchen. Then I would use pressure because the scrubbing takes 45 mins. to 1 hour, depending on how far out of level your stone is. With the pressure I use I'd likely break
the glass plate. I have done several using a SiC coarse then fine stone. Good luck. DM
 
From the pictures your stone doesn’t look too dished so a bit of 30 to 60 grit silicon carbide powder should do fine.

I lap stones like this on a 18”x18” ceramic tile.
If you don’t have to lap much conditioning should only take a few minutes.
 
Dave,
I'm guessing in the video he's saying "aluminum oxide abrasive grains". If so, the materials needed might cost more than a new Arkansas stone unless I can find a better source than eBay of Amazon.

However, I think we're zeroing in on the information I was hoping to find. It seems my grit guess was close if it is a 'hard' Black Arkansas stone.
https://www.sharpeningsupplies.com/What-grit-is-a-Hard-Black-Arkansas-Stone-W183.aspx

Mr. Wizard's posted video also shows to progress up in grits - ok that's what I was hoping to discover.

So, materials. I'm thinking silicone carbide powder might do the same job and it's about 1/2 the price.

I've got 2 old mirrors in the basement that I can use as the glass surface and a work area so I don't make a mess in the house.

This video, eventually, at 22:44 gets to talking about what I think I'm dealing with.

He mentions "silicone carbide paper," whet/dry I assume, for the finer grits.

On a side note, last night I ordered a "Spyderco Bench Stone Sharpener with Storage Case Medium"

========
Willic -

Thanks for the confirmation on the silicone carbide powder.
I'm assuming the "conditioning" you mention would be the higher grit silicone carbide wet/dry papers
taking it up to 1200 grit or so.

Thank you both!
 
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willc said:
From the pictures your stone doesn’t look too dished so a bit of 30 to 60 grit silicon carbide powder should do fine.

I lap stones like this on a 18”x18” ceramic tile.
If you don’t have to lap much conditioning should only take a few minutes.
Click to expand...

Willic - will 40/70 do it?
 
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A At1Rest Silicon carbide (SiC) is more commonly used than aluminum oxide. Ideally a grit that has a single grade, e.g. #60, rather than e.g. 46/70 is more even and will work more smoothly while lapping, but the split grades will still work well. You can get a set of SiC grits for rock tumbling from hobby lapidary shops, or online. I have just learned that it is against the forum rules to post links to retailers, including Amazon, so I cannot do that, however if you search Amazon or eBay for "tumbler grit" you will find a lot of options, e.g. there is a 6 grit kit for 3lb tumbler on eBay for $11.99 with free shipping that includes:

  • One 3 oz. package coarse silicon carbide (46/70 grit) used in Step 1A (optional - for harder stones)
  • One 3 oz. package coarse silicon carbide (60/90 grit) used in Step 1B
  • One 3 oz package medium silicon carbide (120/220 grit) used in Step 2
  • One 1.5 oz package pre-polish aluminum oxide (500 grit) used in Step 3A
  • One 1.5 oz package pre-polish aluminum oxide (1000 grit) used in Step 3B (optional -for softer stones)
  • One 1.5 oz package polish aluminum oxide used in Step 4
12" polished granite floor tiles work well as a base for lapping, and are under $5 each here (locally), but check it with a straightedge as some are not as flat as you would like.
 
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At1Rest said:
Willic - will this do it?
https://www.amazon.com/Fundamental-...coarse&qid=1555256716&s=toys-and-games&sr=1-4
Click to expand...

That would work but it is a bit more expensive than you would pay at a site dedicated to lapidary stuff.

I use my course grits on oil stones and if the stone is lapped flat already I just go light over the wet SiC a few passes and that will rough up the surface.

India stones will need more time and pressure but Arkansas stones condition pretty easily.
 
At1Rest said:
I've got 2 old mirrors in the basement that I can use as the glass surface and a work area so I don't make a mess in the house.
Click to expand...
I'd be EXTREMELY cautious there (in other words don't do it) . . . most mirrors are thin glass and could (would) crack in no time. You need thick glass on the order of 3/8 (10mm).

The reason for not lapping the razor stones, and I realize now there isn't much chance thats what your stone is, is that the razor stones are like a coarse grained brick with a thinnish layer of a coating fired onto it to create the working surface. Lapping it can cut through to the much more coarse core of the stone. Or so I have been warned will happen. I'm not a razor dude.
 
For the cheeper Silicon Carbide (what I have) in many grit sizes check jewelry making suppliers and rock shops (lapidary / rock collecting).
 
Just go to Walmart and buy various grits of silicon carbide automotive wet/dry sandpaper. 320-400 grit.
You do not need to finish the stone to a high grit.
Wet the paper on a hard, flat surface and move the stone in a figure 8 pattern.
It's not rocket surgery.
 
Wowbagger said:
I'd be EXTREMELY cautious there (in other words don't do it) . . . most mirrors are thin glass and could (would) crack in no time. You need thick glass on the order of 3/8 (10mm).

The reason for not lapping the razor stones, and I realize now there isn't much chance thats what your stone is, is that the razor stones are like a coarse grained brick with a thinnish layer of a coating fired onto it to create the working surface. Lapping it can cut through to the much more coarse core of the stone. Or so I have been warned will happen. I'm not a razor dude.
Click to expand...

Thanks for the warning on the mirrors. I'll find some ceramic tile or thick glass.
Good info. on the razor stones. Yea. this stone seems very consistent in it's texture when looking at the side. It doesn't seem possible that it was treated with an outer layer.
 
Bill DeShivs said:
Just go to Walmart and buy various grits of silicon carbide automotive wet/dry sandpaper. 320-400 grit.
You do not need to finish the stone to a high grit.
Wet the paper on a hard, flat surface and move the stone in a figure 8 pattern.
It's not rocket surgery.
Click to expand...

Thanks Bill - I do like using papers, but I also want to try the SiC powder so I ordered a small 6 pack.
 
Update:
So, the SiC power worked really well. The 18" x 18" ceramic tile is great also.
The coarse grits flattened out the dishing really fast.
I took it up to 1000 grit just to see what would happen. 500 and 1000 didn't seem to do much of anything but the stone was sticking to the ceramic tile when trying to lift it off.
It's really flat now and smooth to the touch.
The whole process was pretty fast and easy.
The bad side of the stone still has 1 divot in it but I can just stay on the good side which is totally flat.

Thanks everyone for the guidance. Mission accomplished.
 
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