This review follows on from a post by Giel:
http://aussielapidaryforum.com/forum/index.php?topic=6670.msg58504#msg58504Part 1 : The UnboxingI received two disks from Bert in the Netherlands today, postage took a month to Tasmania under the current pandemic conditions. I purchased a 20/28 (800 grit) and a 63/80 (200 grit) disk. The following are my first impressions of the disks. Note that I have no interest, financial or otherwise, with the manufacturer of these disks.
The disks were packaged very well, there's definitely no way that they could get damaged unless a steamroller ran over the package.
Upon picking them up and handling them, my first impression was that these disks are
very well made. They are manufactured by a craftsman. My next thought was that there's certainly nothing rubbery here - The cutting surface is very hard, there is no noticeable "give" when pushing hard with a fingernail, there is no way I would have picked the disk surface to be made of a rubber compound.
Apparently they are made out of "ebonite", a rubber with 40 to 60% sulphur, which after vulcanisation becomes rock-hard.
Because the diamond is embedded in rubber, the particles sink/spring back in the rubber when cutting, that is reportedly why they leave a very fine finish for the grit size. There is about 100 carats of diamond powder in a coarse lap. (less in the finer grits)
These laps are apparently suitable for cutting all gem materials.
The "sintered diamond" ebonite layer is 3 mm thick, attached to a solid 15mm thick backing plate made of some sort of tough, reinforced phenol resin material. The 3mm layer of diamond impregnated cutting material is comparable thickness-wise with a typical sintered bronze lap. The longevity of the impregnated ebonite layer is unknown at this stage - only time will tell.
The disk width is 150mm, and the central hole sits snug on my Facetron. There is no way you would get any flex in these disks. If these disks cut even half as well as they feel in the hand, it will be a win.
Now, I must add that I have never been lucky enough to have used/owned a traditional sintered bronze disk before, I have wanted to, but they are near impossible to source in Australia, and prohibitively expensive from overseas. So my comparisons will be with diamond-impregnated epoxy topper discs, such as the Lightning Laps and also with the ubiquitous Chinese-made diamond plated steel topper disks.
I see these disks potentially filling the gap somewhere between thin, short-lived topper disks and long-lasting sintered bronze disks. Coming in at a fraction of the price of the bronze disks (assuming you can even get them), if these disks cut nicely and last even moderately well in comparison, then they will be very competitive.
I believe that these ebonite disks can also be re-surfaced by the user with a sheet of glass and some wet and dry paper, thereby extending their lifetime.
I cut mostly quartz, and given its brittle nature, I guess if these disks perform well with quartz, they should work with most materials.
Stay Tuned for Part 2: The Cutting Begins...
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