Cleaning diamond stones

So I downloaded the Imgur app but can't seem to get the pictures to upload here.

I have tried letting the BKF sit anywhere from 5-20 minutes but still nothing has changed.
I would have never thought that I would have ripped/pulled the diamonds out by sharpening twenty knives or so, and most of them being Case CV. I'm going to keep messing with imgur and cleaning to see if I can get something figured out one way or another. I do appreciate all of you jumping in with the fast responses and help.
 
I clean my diamond plates with dish soap and water.

Anyone know about the eze-lap plate bonding? The website says a "stainless alloy", I guess that could be nickel...
 
Nagura stone. Good stiff brush.
Keep it wet, of course.
You'll thank me.

Recently I acquired a CKTG diamond plate for edge pro.
It looked like a relic dug up out of the garden.
Caked with rust, hardened swarf from who-knows-what,
this thing was a mess and most people would've just thrown it away.
Dish soap and water; eh.
BKF; eh.
Rubbing with nagura stone and water; like brand new in 5 minutes.
Inspected under 230x; Like new. Shiny diamonds.

Gleaned from some previous posts-
It's always good to start with the least harmful method.
Using plenty of water, like under the faucet in some cases, is always a good idea flattening stones, etc.
Common sense, going easy, and keeping things clean in the first place makes life easier.
 
Diemaker said:
Are you sure? The nickle alloys I am familiar with on plated tools are very hard and wear resistant to erosion from the slurry. I machine a lot of stone and some of my tools are plated so I have a lot of experience with this, but their bond is a vacuum brazed nickle/ reactive metals alloy. Some tools last for years grinding stone and I have never retired one because the bond was too worn.
Click to expand...

You also use high volume of flood coolant while grinding, yes?
 
Yes, but I push them until I have problems then back off a little. Flushing is not that efficient, nothing like directed flushing in creep-feed grinding. With some stones flushing the swarf out is the limiting factor in how fast I can feed. Not quite the same use but my tools are much smaller than these big plates and they remove 50-300 lbs of stone in their lifetime. I figure the brazing alloys have to be similar because it is extremely difficult to get a metal to bond to a diamond crystal, hence the reactive metals in the nickle alloy.
 
Bill DeShivs said:
The diamonds on these "stones" are held in place by electroless nickel plating. The nickel is relatively soft-and using stone slurry can quickly damage it.
Click to expand...

These are before and after (5 minutes of use) images of the same spot on a DMT plate - you can clearly see how soft the nickel is and imagine how easy the plates are to damage if you expose them to loose coarse grit.

dmtc_new_05.jpg

dmtc_broken_in_05.jpg
 
Nice Todd! Thank you sir. Also, the braze alloys used for industrial tools are a different alloy than the electroplated nickel that's usually used for diamond sharpening plates. One is brazed at high temperature, one is electroplated (sometimes electroless THEN electroplated). The latter is a lot weaker. The coolant doesn't need to be high pressure and directed right at the cut - just a decent flow to flush particles away - in addition, industrial grinding wheels are run at a high speed - many of the removed particles are thrown out just by the rotation of the wheel and shot away from the area. On top of all that, a grinding wheel is only making line contact, not contact over a large surface area. Much harder to get particles stuck between the abrasive surface and the stone.
 
Todd, that photo just shows destruction of the diamonds, not swarf erroding the bond. With stone you won't see that kind of destruction, you have to grind on steel for that.

eKretz, some of my tools get up to 180 degrees of contact, and are the ones that see the most use/abuse. Still never retiered one because of the bond eroding too much.
 
Again, many of the industrial wheels are brazed, and the bond is much stronger than electroplating. I'd bet your wheels are of the brazed variety. These processes are NOT the same. The coolant flushing helps a lot for even electroplated diamond plates. How are you grinding anything with 180° of contact? I was a tool maker for a couple decades and the only time we got anywhere near that kind of contact was when using a cup wheel.

And BTW I'm not talking out my @ss here, I have actually had diamonds stripped right off a diamond plate while making slurry on stones.

Atoma 1000 with stripped diamonds from slurry making; this plate has never been used for anything else:
20180905_180235.jpg


Close up (25x) of good surface:
20180905_180136.jpg


Close up (25x) of stripped off diamonds showing them flush with the base layer:
20180905_180151.jpg


You can clearly see in the last photo that the nickel layer has been abraded - and that it was 3-body abrasion. The slurry got caught between the nickel layer and the stone being lapped and abraded the nickel, removing the diamonds.

I also know many guys who use similar high grit diamond plates for making slurry on JNats and have had the diamonds stripped off. This is something that happens in real world use. Coarser diamond plates (325 and below) are much more likely to retain enough space between the nickel base layer and the item being lapped so this doesn't occur - but it would still be unwise to do for very long without constant flushing with running water.
 
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Diemaker said:
Todd, that photo just shows destruction of the diamonds, not swarf erroding the bond. With stone you won't see that kind of destruction, you have to grind on steel for that.

eKretz, some of my tools get up to 180 degrees of contact, and are the ones that see the most use/abuse. Still never retiered one because of the bond eroding too much.
Click to expand...

The metal swarf isn't going to cause any damage, it's the LOOSE abrasive that can get between the diamonds and scratch the relatively soft nickel. The damage in the above image was caused by loose diamonds, but the same occurs with loose aluminum oxide or silicon carbide from a whetstone.

Below is a diamond with metal swarf impacted on the surface. I don't think it's really much of a concern - I'd expect it be be cleared off with normal use.

dmt1200_breakin_09.jpg
 
Some of my tools are "routers", think end mill without flutes with diamond in their place. Yeah, 180 degree contact isn't good but the tools seem to live through it. The nickel alloy braze is still mostly nickel. I have tried some tools with electroless nickel plating and they worked almost as well, the biggest problem was the quality made you think they were made in sombodys garage in China.

I would love to see electron microscope photos of the plate with the diamonds cleaned off. From the looks of it they came off quite easily. I figure if the bond can hold the diamond in place while grinding steel then holding up to some abrasive swarf isn't an issue.
 
The problem is that the swarf rolls and tumbles when it's pinned between the two, and it digs under the diamond, releasing it from the bond. Don't forget this is a 1000 grit plate. Nickel is nothing compared to the hardness of even natural abrasives. Most of your grinding tools are probably FAR coarser also based on my experience using them. And again - the brazed diamond tools are WAY stronger.
 
I don't have an electron microscope, but I can go up to 240x or so. Here are some closer-up shots of the Atoma plate in the unworn and worn areas with good contrast lighting so surface topology is a little more visible:

First, a couple shots of an undamaged area. First shot is taken with ring-light. diamond clusters are a little less than 0.5mm across:

1895223821217.jpg~original


Next is a contrast shot clearly showing the diamond stands proud of the nickel plating across the whole cluster. You can see that there are some stray diamonds in the nickel plate between clusters also:

189522409338.jpg

189522409338.jpg~original


Now a ring-light shot of the worn area; 3- body abrasion is plainly visible,along with a small amount of 2-body:

189522263230.jpg~original


And a contrast shot again showing the plainly visible 3-body and a small amount of 2-body abrasion:

1895223712431.jpg~original


A little higher contrast shot to get a better idea of surface topology. Compare this shot to the high contrast shot of the unworn area:

1895223619752.jpg~original
 
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I use BreakFree CLP to clean my diamond hones. Let it sit over night for best results but even a few minutes will lift the swarf, then wipe with a soft clean cloth.
 
Surprised to read that others view BKF in the same way I do....very highly! I have always heard that Comet/Ajax were more coarse, but after a little research, the chemical makeup of BKF and Comet is very different. BKF uses Oxalic Acid (very effective on rust), while Comet uses calcium carbonate. For whatever that's worth!
 
Comet & Ajax work mainly due to abrasive action of the calcium carbonate, for scrubbing stuff clean. There are some chlorine-based chemical stain removers in it too, but the rest of it's cleaning attributes are due to the abrasive scrubbing action. Sometimes that abrasive is enough, sometimes it isn't.

BKF relies on the chemical action of the oxalic acid to do most of the cleaning work. It's reactive to oxides of iron in particular, which is why it works so well in cleaning hones, literally dissolving the steel swarf. Oftentimes, you don't even need to scrub the surface to clean it. Just let it sit wet (with some water) for a minute or two, and then rinse it off.

I was fully sold on BKF when I first tried it in removing rust stains on a piece of kitchen stoneware. For years, I'd lived with some stains left on a dinner plate in stoneware, the stains having appeared after being left in a wet sink too long with some flatware laying on it. I'd long-ago assumed the stains were there forever, as they had never come off with anything I'd tried. When I finally read BKF was good at removing rust, I just dabbed a paste-mix of BKF & water onto the stain, let it sit for about a minute, then literally wiped the years-old rust stain right off the plate with a damp rag. The plate looked as if the stain had never been there in the first place, with not a hint of it visible anymore. I was blown away.
 
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