amazon won't give me the same listings because I'm in the states, but if they are around 20 pounds, 8x3", steel core and two sided, and they don't have colored plastic showing in the grid, etc, they are all about the same.
Monocrystalline diamonds are cheap. At the outset of using the stone, you'll end up tearing loose any diamond that sticks up (for all brands - atoma's arrangement in piles makes it so there's not much exposed standalone, but they do have a different feel, especially in coarse grits, that some people don't like), and it will get "slow quickly". And then it will wear slowly after that, which is where you won't notice just how slow it gets unless you compare a waterstone or something at some point and realize that it's a lot faster than your diamond hone.
But that said, yes, don't buy from alibaba - I was making the point that when these things are $8 each, some sellers will sell them for $20, some will try for $45 and have their brand printed on them (you can see in the alibaba listings that this is a service offered - get the same item but have your brand printed on it), and some will try for much more. if there is a true value proposition, they should be able to state what it is.
At one point, trend had a video up talking about how much better the lapping fluid is than anything else. well, if you like a mix of naptha and mineral spirits, maybe it is. In the states, their marketers at wood shows would tell people "you can't use WD 40 on stones" without being able to explain what was so much better about the lapping fluid. so, on youtube, I posted the SDS contents in the video (mineral spirits and a slow drying type of naptha) and asked "why is it $350 a gallon equivalent (at the time) for a mixture of naptha and mineral spirits" and instead of answering, they removed the entire video. Do I know for sure they removed the video because of my comment? of course not, but it seemed a little odd that it was gone the next day.
At any rate, microcrystalline diamonds have always been marketed as "a better option" because they're not friable, but a couple of folks a decade ago told me that polycrystalline plates are better, but more expensive, and at the time, ezelap at least had a mixture of the types.
I use sharpening stuff pretty heavily because I do about half making things, and half making tools. The toolmaking is very hard on sharpening stuff and it'd be lovely to have something like an electrocoat plate that really didn't wear, but they all do, and quickly. Some of the pictures I've taken of surfaces make it look like most of the diamonds are still there after all of the big ones are gone and after very heavy use, but they're probably just dull or the ones remaining have no real sharp bits oriented toward the top.
So, I have a lot of exposure to this and heavy use over 15 years, and am keenly interested in not wasting time. But safe to say, when someone touts to you that they have plates that are 30 years old and as good as new, it's because they don't know they're not. I think if you have any semblance of electroplate let even after 20 years, you'll still get some cutting ability, but the biggest shortcoming people have sharpening is not finishing the actual job and thinking they did, so a very slow stone that you think is fast is detrimental.
For toolmaking where I'm working with high hardness tools and doing final prep, obviously a 4 or 10 to 1 difference in speed is noticeable. The solution industrially is not that there's a magic solution, it's just to use something else and generally have it be a machine powered method.
So, what's my suggestion? buy a couple that are around 20 pounds from amazon - 300/1000 or 400/1000 - whatever it is. Use one of them but the other sparingly. when they get really far apart if you're lucky enough to do the sharpening that causes that to happen, because of the volume of work you're doing, just replace the slow one or set it aside for later.
I've tried every trick to revive the slow plates - cleaning them, adding loose diamond grit to them and just using them as a lap, but it's all sort of a half way measure.
The $100+ hones won't last any longer, either. The more expensive plates that were made in the US sometimes had the diamonds on slightly neater, but it's not exactly a huge differentiator.
Atomas lose diamonds less quickly, but they do also get very slow over time.
) just cleaning, bedded in wire edges etc. A bit of old stone would do instead of the Diapad, which I just happened to have.
