# How to remove a sharpening stone from a plastic base



## Michi (Jan 27, 2019)

I just received my Cerax 3000 stone. Of course, it came in one of those plastic boxes, glued to a plastic base plate. My other stones don't have a base, and I don't like the plasticky look. Besides, without a base, I can use both sides of a stone. (I reserve one side for single-bevel knives, which must have an absolutely flat surface; the other side I use for double-bevel knives, where I can tolerate some minor dishing before I flatten the stone again.)

So, I decided to get the stone off its base. I looked around some, but my googling didn't help much. I found a few threads about this in various forums; some people suggested heating with a hair dryer, others suggested hot water, but none offered a definitive answer. I didn't like either suggestion much because I was worried that sudden temperature change might cause stress fractures.

Here is my method, which worked for me.

A warning before you jump in and try this: I did this with a soaking stone. Soaking stones are sintered, meaning that they don't mind high heat because they are made by baking them in an oven. I have no idea what would happen if I were to try this with a splash-and-go stone that uses a resin binder. (It might destroy the stone, or it might be fine; I simply don't know.)

The stone was glued onto the plastic base with epoxy. Here it is out of the box:




I didn't want to try and pry the base off; too much risk of breaking the stone or taking chips out of the side. Epoxy gets soft at high temperature. How high depends on the particular glue that was used. A little googling shows that most epoxies get soft between 70 ºC and 160 ºC. So, I decided to put the stone into my oven.


I have an electric oven that allows fairly precise (5 ºC) temperature control even at low temperatures (down to 30 ºC). I started out by setting the oven to 55 ºC and left the stone there for 15 minutes. The idea was to bring the stone up to the necessary temperature slowly, so it would heat evenly without developing stress fractures. I then increased the temperature to 65 ºC and gave it another 15 minutes. I then checked if the glue had softened.

To avoid temperature shock, each time I removed the stone from the oven, I put it down on a towel. (Putting the stone on a cool surface, such as a stone bench top, risks having the stone crack as it cools down unevenly.)


No change at 65 ºC, still firmly attached, so I upped the temperature to 75 ºC. 15 minutes later, I could lift off one side of the plastic base a little, so the glue had started to soften.


Back into the oven it went, at 85 ºC for another 15 minutes. This time, the base plate came off quite easily. Here is what it looked like:


The glue itself was still very firm, but the high temperature had obviously weakened the bond with the plastic.

I was hoping that, if I heated the stone further, the glue would soften enough to scrape most of it off. So, I put the stone back in and gradually increased the temperature to 165 ºC over a 45-minute period. When I checked again, the glue wasn't showing any signs of coming off any easier. It was a little more gooey on the surface, but still way too firm to scrape off.

So, I put the stone back into the oven and dialled the temperature down to 80 ºC and waited until the temperature had dropped that far, and then gave it another 15 minutes before I turned the oven off, leaving the stone in there. Again, the idea was to allow the stone to cool down gradually to avoid stress fractures.

With the stone back at room temperature, I thought about how to get the remaining glue off. Googling shows that epoxy will dissolve in acetone. To avoid wrecking my brand-new stone, I splashed some acetone on a $20 garbage stone I have, to check if there was any staining or other chemical reaction. That test turned out OK, the acetone left no trace once it evaporated.

Next I tried to use the acetone to remove the glue. Abject failure. I got the surface just a little gooey, but I estimated it would take me an entire day to remove the glue that way. So, onto my sink bridge it went (after soaking it first, of course), and I had a go with my Atoma 400 plate. Here it is after maybe 30 seconds of sanding:


You can see the little bits of epoxy that got abraded and then stuck together to form little blobs of glue (much like the bits of plastic left behind by an eraser). The blobs got in the way of the Atoma plate, which, in short order, started rolling on top of the blobs instead of abrading more epoxy. Frequent rinsing of the stone and the plate took care of that. Within five minutes, I had all the glue off:


There is a small slightly brighter area on the stone near the right side. I don't know what caused that. There is definitely no glue left; it might have been like this when it was manufactured.

For comparison, this is the original top side:


The printing on the side of the stone faded a fair bit while it was in the oven. It looks like the pigment in the ink broke down in the high temperature.

Other than that, there were no ill effects. The stone works just as well on the original top side as it does on the side that was glued onto the base.


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## Matus (Jan 27, 2019)

I am putting plasic bases on most of my synthetic stones


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## Michi (Jan 27, 2019)

Matus said:


> I am putting plasic bases on most of my synthetic stones


Not a problem. Send them to me if you change your mind about those bases


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## Knife2meatu (Jan 27, 2019)

Matus said:


> I am putting plasic bases on most of my synthetic stones



After hearing, from somebody cleverer than myself, about gluing a plastic base to their Bester -- a base plate which doesn't exceed the dimensions of the stone, crucially -- I've been mulling over trying to find some 10 mm thick plastic to do the same myself.

A base to stabilize the stone and avoid cracking; add thickness and strength when it gets thin; while also being compatible with whatever universal holder one would use anyway! It seems like such a better design than the larger bases which double as built-in stands; it's a wonder that virtually only Shapton glass stones implement this design -- and I'd think those only do so because they're so thin from the start.


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## zitangy (Jan 27, 2019)

if using solvent to wipe off the epoxy, the solvent will dissolve the epoxy and wld get into the pores of the stone... just a thought..


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## Michi (Jan 27, 2019)

Knife2meatu said:


> AI've been mulling over trying to find some 10 mm thick plastic to do the same myself.


A Google search for "acrylic sheets" for my area comes up with a whole bunch of plastic manufacturers. They sell acrylic in various thicknesses and also will cut to size. 

Alternatively, find some aluminium bar of the right width (it wouldn't need to be exactly the same width as the stone, as long as it's close) and cut it to the length you need, or have it cut to the measurements you want where you buy it.


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## Knife2meatu (Jan 27, 2019)

Michi said:


> A Google search for "acrylic sheets" for my area comes up with a whole bunch of plastic manufacturers. They sell acrylic in various thicknesses and also will cut to size.
> 
> Alternatively, find some aluminium bar of the right width (it wouldn't need to be exactly the same width as the stone, as long as it's close) and cut it to the length you need, or have it cut to the measurements you want where you buy it.



Oh, I probably wouldn't go down either of those avenues: acrylic in that thickness is going to be more expensive than the project demands. And aluminium seems like a poor choice on account of widely disparate thermal expansion coefficients, as well as cost.

I only said plastic because that's what the person who sparked this idea for me used; and because the sharpening stone manufacturers using bases make them out of plastic, for the most part. If I'm going to do it, I'm probably going to use some inexpensive b-grade ceramic tiles which can be had for pennies; in fact, I have 300 lbs of the stuff I got for $20 a while back -- very easy to find extra tile, in my experience. And I think it might give the synths a more "stony" feeling, aesthetically at least -- if that makes any sense to anybody but me, is a different matter entirely.


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## Michi (Jan 27, 2019)

The tile idea sounds good, if you have a cutter or can have someone cut them for you.

At the narrow range of temperatures the stones are used, I suspect that different expansion coefficient wouldn't cause any problem, especially with a glue that retains flexibility. (Two small dabs of silicone would probably work well.)


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## Knife2meatu (Jan 27, 2019)

I'm sure you're right about the expansion -- particularly considering that I'm now looking at the thermal expansion of plastics vs. metals for the first time and realizing that plastics expand roughly an order of magnitude_ more_ per unit temperature change than metals. Always good to curb at least another new modicum of my ignorance. Of course, the point about not using nice Al flat bar for this remains, though.

Silicone is indeed an interesting choice for adhering the stones. I've wondered whether type 1 or 2 would be the least likely to give the fragile Choseras fits.


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## Matus (Jan 28, 2019)

I am using 10mm thick hard PVC (in ugly gray). I cut it just a little wider (like 2-3mm) that the stone and about 2cm longer. I use epoxy to glue the stone on the plate. The reason is that the stone will eventually get thin and will need some support anyhow. My Gesshin 400 has just a few mm left. Also - the base offers a bit of protection to the stone when stored in water with other stones.

Just yesterday I glued my Gesshin 2000 and Gesshin Synthetic Natural stones to a PVC base. I may put some lacquer on the side of the stones, but I do not expect that to be necessary. I did that on Bester 220 to keep the water seeping through in matter of seconds. The lacquer helped a great deal to mitigate that.


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## zitangy (Jan 30, 2019)

[QUOTE="Knife2meatu, post: 592794,

Silicone is indeed an interesting choice for adhering the stones. I've wondered whether type 1 or 2 would be the least likely to give the fragile Choseras fits.[/QUOTE]

just a feedback... my preferred juice for gluing jnats to base is hot glue.. you can make it lumpy and thus support uneven bottoms of stone... and melts at lower temp than epoxy. None has dropped off..

for a while i did use them for handles.. hot water on the blade and it melts. Otherwise its firm enuf.... i believe so.. 

have fun


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## Michi (Jan 30, 2019)

Silicone makes for quite a strong glue, especially when bonding flat things together. The advantage of silicon is that it stays soft, so you can cut it quite easily, and it's fairly easy to remove. (Often, you can peel off a hole sheet of it in a single piece.)

On the other hand, the specific glue for sticking a stone to a base is probably not that important. I assume that the stone will stay on the base until it's finally worn out. What little of it is left by then can be broken off. Or just throw the whole thing away and start again.

To be honest, I don't expect to wear out any of my stones inside of five or ten years.


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## M1k3 (Jan 30, 2019)

If you want to attach the stones to something, what about glass? Can be cut to the same size as the stone. Shapton does it lol


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## M1k3 (Mar 3, 2019)

Question for everyone to piggyback on this, at what temperature does resinoid bond in King 6k stone start breaking down?


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## Ivan Hersh (Mar 3, 2019)

I have received some stones with their bases glued on, it has not caused any problems so they will remain glued on.


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## M1k3 (Mar 3, 2019)

Ivan Hersh said:


> I have received some stones with their bases glued on, it has not caused any problems so they will remain glued on.



I'd like to take apart my king combo stone.


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## Ivan Hersh (Mar 3, 2019)

M1k3 said:


> I'd like to take apart my king combo stone.


So there has been posted advice as to how to do it, so just follow there instructions and good luck.


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## Knife2meatu (Mar 3, 2019)

M1k3 said:


> I'd like to take apart my king combo stone.


Good luck with that. If you're inquiring about the temperature at which the 6k would breakdown, is it safe to assume that you're hoping to heat the stone enough to be able to separate both halves?


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## Michi (Mar 3, 2019)

Knife2meatu said:


> If you're inquiring about the temperature at which the 6k would breakdown, is it safe to assume that you're hoping to heat the stone enough to be able to separate both halves?


If that's the case, I suspect that it would be a really risky thing to try. For one, by the time glue is hot enough to actually separate the two halves, it'll be quite difficult to handle the stone. I'd also be worried about bits of stone breaking off. And I have no idea whether the binder in the 6k wouldn't disintegrate before the glue that holds the two halves together.

If you do try this, let us know how it went please.


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## Ivan Hersh (Mar 3, 2019)

Michi said:


> If that's the case, I suspect that it would be a really risky thing to try. For one, by the time glue is hot enough to actually separate the two halves, it'll be quite difficult to handle the stone. I'd also be worried about bits of stone breaking off. And I have no idea whether the binder in the 6k wouldn't disintegrate before the glue that holds the two halves together.
> 
> If you do try this, let us know how it went please.


My King 1000/6000 has two one inch stones glued to a piece of rubber in the center, this King Combo can be found for around $28US i feel if these stones were badly worn i would just buy another before going to all this ungluing trouble.

Now the other stone i have that is just one stone and glued to it's plastic base, it's really thick, and will be a long time before it's badly worn, i don't see going to the trouble to ungluing the stone from it's base.
And as others have posted you might just end up with an unglued ruined stone.


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## M1k3 (Mar 3, 2019)

Ivan Hersh said:


> So there has been posted advice as to how to do it, so just follow there instructions and good luck.



"I have no idea what would happen if I were to try this with a splash-and-go stone that uses a resin binder. (It might destroy the stone, or it might be fine; I simply don't know.)" -Michi


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## M1k3 (Mar 3, 2019)

Ivan Hersh said:


> My King 1000/6000 has two one inch stones glued to a piece of rubber in the center, this King Combo can be found for around $28US i feel if these stones were badly worn i would just buy another before going to all this ungluing trouble.
> 
> Now the other stone i have that is just one stone and glued to it's plastic base, it's really thick, and will be a long time before it's badly worn, i don't see going to the trouble to ungluing the stone from it's base.
> And as others have posted you might just end up with an unglued ruined stone.



I have the KDS version but I would like to take them apart.


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## Ivan Hersh (Mar 3, 2019)

M1k3 said:


> "I have no idea what would happen if I were to try this with a splash-and-go stone that uses a resin binder. (It might destroy the stone, or it might be fine; I simply don't know.)" -Michi


 Well i am sure waiting for someone to try it, and let us all know how well it worked or did not work.


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## M1k3 (Mar 3, 2019)

Ivan Hersh said:


> Well i am sure waiting for someone to try it, and let us all know how well it worked or did not work.



LOL I just might. And if I fail, good reason to get some new stones


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## Ivan Hersh (Mar 3, 2019)

M1k3 said:


> LOL I just might. And if I fail, good reason to get some new stones


I don't need reasons to buy new stones i just keep buying them.


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## Michi (Mar 3, 2019)

M1k3 said:


> LOL I just might. And if I fail, good reason to get some new stones


If I were to try this, here is what I would do:

Put about half an inch of water into a smallish pot. Prop your stone in there such that only one corner is below the water level. Start heating the water. Check occasionally to see what happens to the stone, especially the white 6000 side, which uses resin binder. (As far as I know, the brown 1000 side is sintered.)

If you get all the way up to boiling point with no damage to the stone, you should be good. If it goes badly wrong, the worst that can happen is that you lose a small corner of the stone.

If all this works out OK, let the stone dry again, then use the oven method I outlined above. Bring up the temperature gradually to maybe 100 ºC or so, checking occasionally as to how things are going. Be careful about temperature shock when you handle the hot stone. Put it down on a folded towel on top of a wooden board or some such. With oven mittens, or similar, you might be able to separate the two halves. You could try prying with a spatula, but be cautious about breaking off bits of stone.

Michi.


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## Ivan Hersh (Mar 3, 2019)

Michi said:


> If I were to try this, here is what I would do:
> 
> Put about half an inch of water into a smallish pot. Prop your stone in there such that only one corner is below the water level. Start heating the water. Check occasionally to see what happens to the stone, especially the white 6000 side, which uses resin binder. (As far as I know, the brown 1000 side is sintered.)
> 
> ...


I wonder what would happen if they used a microwave oven, it heats from within an item, it just might excite the glue and do nothing to the stones.
Power it on a while stop and see if it is coming apart.


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## Knife2meatu (Mar 3, 2019)

Michi said:


> [...] especially the white 6000 side, which uses resin binder. (As far as I know, the brown 1000 side is sintered.)


I think they're both resinoid.


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## M1k3 (Mar 3, 2019)

Michi said:


> If I were to try this, here is what I would do:
> 
> Put about half an inch of water into a smallish pot. Prop your stone in there such that only one corner is below the water level. Start heating the water. Check occasionally to see what happens to the stone, especially the white 6000 side, which uses resin binder. (As far as I know, the brown 1000 side is sintered.)
> 
> ...



Thanks, will do. The 1k side is fired clay.



Knife2meatu said:


> I think they're both resinoid.



See above response


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## Michi (Mar 3, 2019)

Ivan Hersh said:


> I wonder what would happen if they used a microwave oven, it heats from within an item, it just might excite the glue and do nothing to the stones.
> Power it on a while stop and see if it is coming apart.


I suspect that this would almost certainly not work. Microwaves have a wavelength that specifically matches the dipole moment of water molecules. It's highly unlikely that the glue would happen to match that.

Edit: I guess you could try, but I wouldn't put just the stone into the microwave. Instead, add a bowl of water beside the stone, to make sure that the microwave has enough load. That way, even if neither the stone nor the glue absorb any microwaves, the oven won't get damaged.

Needless to say, I'd do this carefully, in short bursts, so you can figure out whether the stone actually gets hot or not. If it doesn't, nothing is lost; only the water will get hot.


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## M1k3 (Mar 3, 2019)

Michi said:


> I suspect that this would almost certainly not work. Microwaves have a wavelength that specifically matches the dipole moment of water molecules. It's highly unlikely that the glue would happen to match that.
> 
> Edit: I guess you could try, but I wouldn't put just the stone into the microwave. Instead, add a bowl of water beside the stone, to make sure that the microwave has enough load. That way, even if neither the stone nor the glue absorb any microwaves, the oven won't get damaged.
> 
> Needless to say, I'd do this carefully, in short bursts, so you can figure out whether the stone actually gets hot or not. If it doesn't, nothing is lost; only the water will get hot.



I'm not even going to attempt doing it in the microwave. Sounds to iffy. And then there's the wife. I like sleeping in my bed


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## Dave Martell (Mar 4, 2019)

Consider that the manufacturer took added expense to mount their stones for a reason.


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## Michi (Mar 4, 2019)

M1k3 said:


> And then there's the wife. I like sleeping in my bed


_Her_ bed, you mean?


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## Michi (Mar 4, 2019)

Dave Martell said:


> Consider that the manufacturer took added expense to mount their stones for a reason.


Yes. But maybe not for the sake of the stone, seeing that they've been selling stones without the mount for ages. I suspect it's more because they figure that with a "snazzy" base, they'll sell more of them.


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## Ivan Hersh (Mar 4, 2019)

My Naniwa 400 Grit came with it's stone glued onto a nice plastic base, with small rubber inserts in it's feet, it stays solid as it the stone was installed in my standard stone holders.

I was at first somewhat unhappy with glued, but today i find it a really nice thing not having to install it in my holder.

Have a Naniwa 800 Grit arriving Tuesday hope it's base is also glued on.


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## Michi (Mar 4, 2019)

Ivan Hersh said:


> Have a Naniwa 800 Grit arriving Tuesday hope it's base is also glued on.


You should start a new thread: "How to add a sharpening stone to a plastic base"


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## Ivan Hersh (Mar 4, 2019)

Michi said:


> You should start a new thread: "How to add a sharpening stone to a plastic base"


What are you doing up so early?


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## Michi (Mar 4, 2019)

Ivan Hersh said:


> What are you doing up so early?


Having breakfast


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## Ivan Hersh (Mar 4, 2019)

Michi said:


> Having breakfast


Do you happen to subscribe or read Blade Magazine?


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## Knife2meatu (Mar 4, 2019)

M1k3 said:


> Thanks, will do. The 1k side is fired clay.
> [...]
> See above response


I used to share this belief; which I seem to remember being gleaned from internet forum chatter when I first got into sharpening. I've since decided to defer to Cliff Stamp's opinion on the matter. (Proof: www.youtube.com/watch?v=2VCo1_fozD0&feature=youtu.be&t=56 -- He explicitly states that it's a resin bond within a minute of the linked time-stamp.)

While I'm entirely willing to amend my beliefs on the matter once more, perhaps you could back up your assertion?

Having now experimented with a fair number of synthetic abrasive stones in the #1000 grit range, I'd say that I find the 1k King to be distinctly duller sounding when tapped than the sintered/baked stones I've tried. This is a slightly ludicrous test, but it's as good as anything else I can think of at the moment.


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## Michi (Mar 4, 2019)

Knife2meatu said:


> (Proof: www.youtube.com/watch?v=2VCo1_fozD0&feature=youtu.be&t=56 -- He explicitly states that it's a resin bond within a minute of the linked time-stamp.)


Is it possible that he is mistaken?

I have no idea who is right; one way to find out might be to see how much water the stone absorbs. If it's about one third by volume (roughly one sixth by weight), it's sintered. If it's a lot less than that, it's resin.

Michi.


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## Knife2meatu (Mar 4, 2019)

Michi said:


> Is it possible that he is mistaken?


It's certainly possible that he's mistaken.

Looking around earlier to decide how much I cared to argue this point, I've found a number of vendors stating that both sides of the King are abrasives in clay. On the other hand, it wasn't longer ago than last week that I exchanged with someone who was quite convinced the 6k side was resin. But then, I've seen quite official feeling specs on the some websites claiming that the 6k "contains no plastic", which I assume to mean no resin either.

I think I actually have weighed a King 1k with and without water before, for another reason -- I just have no idea where those notes are.


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## Knife2meatu (Mar 4, 2019)

Michi said:


> I have no idea who is right; one way to find out might be to see how much water the stone absorbs. If it's about one third by volume (roughly one sixth by weight), it's sintered. If it's a lot less than that, it's resin.


Found said notes; and the water content is ridiculously close to one sixth by weight; 16.9% more precisely.

And while that is tantalizingly close to what you had predicted, is this kind of porosity exclusively the domain of fired stones? I don't have much experience with resin stones, but if the above is true, then it would hold true that a stone which when soaked releases bubbles in similar quantity to a King or Cerax would necessarily not be resinoid.


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## M1k3 (Mar 5, 2019)

I saw Jon Broida mention it before. Not sure if here or Reddit though.


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## Michi (Mar 5, 2019)

Hmmm… As far as I know, the whole point of resin stones is that they are splash and go. And splash and go stones normally absorb very little water. A resin stone is made by mixing the abrasive into the resin and then letting the whole thing cure. There would be essentially zero air space in the stone; all the space that is not abrasive was filled by the originally liquid resin.

So, if you get one sixth by weight of water into the stone, that's quite a lot. If the King 1000 has about the same density as my average Cerax (pretty much exactly twice the density of water), that's about one third by volume. In other words, one third of the stone is air; I just cannot see that happen for a stone with resin binder.

The 1/6 and ⅓ figure is predicated on the stone having about twice the density of water. Wouldn't be hard to verify by weighing the (dry) stone and working out its volume. If the density is indeed is ~2 g/ml, I'd say it's a safe bet that it's a sintered stone.


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## M1k3 (Mar 5, 2019)

Michi said:


> Hmmm… As far as I know, the whole point of resin stones is that they are splash and go. And splash and go stones normally absorb very little water. A resin stone is made by mixing the abrasive into the resin and then letting the whole thing cure. There would be essentially zero air space in the stone; all the space that is not abrasive was filled by the originally liquid resin.
> 
> So, if you get one sixth by weight of water into the stone, that's quite a lot. If the King 1000 has about the same density as my average Cerax (pretty much exactly twice the density of water), that's about one third by volume. In other words, one third of the stone is air; I just cannot see that happen for a stone with resin binder.
> 
> The 1/6 and ⅓ figure is predicated on the stone having about twice the density of water. Wouldn't be hard to verify by weighing the (dry) stone and working out its volume. If the density is indeed is ~2 g/ml, I'd say it's a safe bet that it's a sintered stone.



I know for sure the 6k side is, doesn't bubble underwater. The 1k side I'm pretty sure is clay and bubbles underwater.


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