Getting a mirror finish on your edge?

[CliffCurry]

Thanks for taking the time to do some testing TC… I had the 1200/1600 but could never get mine to perform well. The 1.4u/6u are definitely of a different hardness… I believe.

I’ve been doing tests and snapping pics all day & wish I had better results to report. I also think I’ve ended the life on one of my well worn 1000 grit diamond paddles using it for lapping like a dummy. I remember reading not to use them on ceramics at some point.

After relapping the .6u with the 1000 grit results were good but still have the occasional deeper gouge mark mucking up my jam.

I see a dmt bench stone at the hardware store for $50 and am tempted to get it to do a full lap job on these suckers.

[Zamfir]

OK, so I did a little testing of my own. But the only lapping plates I had were 400 and 1000 grit. So I lapped my 1200 grit super fine with the 400, tested it on a previously polished bevel, and then lapped it with the 1000 and tested it alongside the 400-lapped ceramic, much as Cliff had done. I didn’t take photos, but can say that the difference was as follows: the 400-grit-lapped scratches were equivalent to the 1000-grit scratches, but were obviously less uniformly distributed. The difference could be said to be similar to that produced by stones which had been “broken-in” and those “not yet broken-in.”

Interesting. Just so I understand your results.
The ceramic lapped with the 400 removed the same amount of material in a given scratch as the ceramic lapped with the 1000grit stone?
It is just that the ceramic lapped with the 400 grit did not have as many scratches and they were less uniform?

Was there a distinct difference in how the differently lapped stones felt while using them?

Thanks!

[tcmeyer]

Yeah, I think that’s a fair assessment, altho I can’t be sure that the ceramic lapped with the 400 actually removed more material. I used one stone at a time for both lapping tests, so I don’t really have a comparative feel for it. Only the visual results.

The main point being: the scratches seemed to be the same width and depth, one was just messier than the other.

[Mr.Wizard]

the difference was as follows: the 400-grit-lapped scratches were equivalent to the 1000-grit scratches, but were obviously less uniformly distributed.

Thanks for taking the time to do some testing TC… I had the 1200/1600 but could never get mine to perform well. The 1.4u/6u are definitely of a different hardness… I believe.

I wonder if the 1200/1600 ceramics are soft enough to work more like regular (synthetic) abrasive stones, whereas the Micro Fine are solid enough not to break down. That would explain both results reported.

[CliffCurry]

Its funny because if we were all standing in the same room looking at the same stones we would probably all agree to what we were seeing and move on after 5 minutes discussion. 😆

I think we are getting to the heart of the matter, especially with Toms test on the 1200/1600. In addition the fine micro ceramic that I mercilessly lapped with a new 100 grit diamond plate…The scratches are highly visible and I will have to work like a SOB to remove then. That stone is TOUGH!

[wickededge]

I think Wizard is right re: the hardness of the 1200/1600 vs the hardness of the micro-fine stones. The 1200/1600 stones behave more like (not entirely, just more so) waterstones than the micro-fines. It’s possible to texture the surface of the micro-fine stones and create different surface features to achieve a variety of results, depending on how you lap them. With the 1200/1600 stones, the surface features you create disintegrate quickly with the first use.

-Clay

[wickededge]

To really test out the differences, I’d recommend getting your sample as polished as you possibly can before trying to compare scratch patterns with the various stones.

-Clay

[Todd Simpson]

FYI, have a look at this link:
Struers

Polishing is typically done with abrasive-loaded cloths. Ken’s Nanocloth is one example, but there are others Ted Pella

I find that finer grit hones will make narrower scratches, but not necessarily shallower scratches. The smaller the grit particle, the smaller the contact area and therefore the larger the pressure for a the same force. Have a look at the scratch depth in the Shapton 2k/4k/8k/16k images:
Blog[/url]

One advantage of polishing cloths is that the pressure exerted by the abrasive particles is moderated by the resilience of the cloth, so the scratches do get shallower with decreased abrasive size.

Lapping film has some of this resilience advantage and is also a great option for polishing.

[Zamfir]

FYI, have a look at this link:
Struers

Polishing is typically done with abrasive-loaded cloths. Ken’s Nanocloth is one example, but there are others Ted Pella

I find that finer grit hones will make narrower scratches, but not necessarily shallower scratches. The smaller the grit particle, the smaller the contact area and therefore the larger the pressure for a the same force. Have a look at the scratch depth in the Shapton 2k/4k/8k/16k images:
Blog[/url]

One advantage of polishing cloths is that the pressure exerted by the abrasive particles is moderated by the resilience of the cloth, so the scratches do get shallower with decreased abrasive size.

Lapping film has some of this resilience advantage and is also a great option for polishing.

Agreed to an extent. I think where this conversation has detoured was what is the best next step from the 1K diamond stone before the strops. This is where the ceramics should fit in. AFter the ceramics then the strops would come into play. I do not think anyone is expecting a mirror finish from ceramics. Lapping films work great but do not last long. Water stones are great but are expensive and messy and need the reshaping. Ideally Ceramics would need the least amount of after care and transition nicely to the strops so you do not have to strop as long if you can knock the scratch pattern down from the 1K to something reasonable for the strops.

This lead into the ever confusing discussion about what grit is ceramics debate..and how does refinishing the ceramics effect the scratch pattern. It would make sense that if you took a hard ceramic that should be fully flat, and then roughed it up with a 100 grit stone, you would have less of the ceramic in contact with the blade edge due to the peaks and valleys you created with the 100 grit stone. Now, the smaller areas that are making contact with the metal would have an increased pressure for force on them against the metal thus possibly making the scratches deeper and more erratic. Why would you want that? The idea is to get a uniform lesser scratch pattern to transition to the strops. ON the softer ceramics the applied surface change with 100 grit would not last as long and go back to more or less flat. It would take longer on the harder ceramics. Although these are very interesting experiments, I would think a person would want to take the ceramic down to as even a surface you could without glazing it so the pressure would be the same throughout and contact area would be similar, and cutting ability would be matched to what it was intended for. I still hold hope that my super fine will work great as this in between stage from the 1K plate to the strops for a mirror.

Now when people talk abut a ceramic being the same material but a different finish… Which is where it feels some people were going here..you need to fully understand what is meant by different finish. Was the finish done by abrasion? Was the different finish caused by a different heating temperature? Was it finished different by adding an element such as some type of gas to the heating chamber during heating, or soaking or the cool down?

Think heat treating here. I would expect ceramic properties can be drastically changed by how they are heated and cooled and in what manner just like metal which would change the structure of how (even the same powder used) ends up being when all said and done. Then there is glazing that could occur or be added. So I think this is why defining a ceramic to a grit is so difficult. I am not sure what means you would use to “polish” ceramics..but I guess it is done. a quick search turned this up:

Ceramic processing is used to produce commercial products that are very diverse in size, shape, detail, complexity, and material composition, structure, and cost. The purpose of ceramics processing to an applied science is the natural result of an increasing ability to refine, develop, and characterize ceramic materials.

Ceramics are typically produced by the application of heat upon processed clays and other natural raw materials to form a rigid product. Ceramic products that use naturally occurring rocks and minerals as a starting material must undergo special processing in order to control purity, particle size, particle size distribution, and heterogeneity. These attributes play a big role in the final properties of the finished ceramic. Chemically prepared powders also are used as starting materials for some ceramic products. These synthetic materials can be controlled to produce powders with precise chemical compositions and particle size.

The next step is to form the ceramic particles into a desired shape. This is accomplished by the addition of water and/or additives such as binders, followed by a shape forming process. Some of the most common forming methods for ceramics include extrusion, slip casting, pressing, tape casting and injection molding. After the particles are formed, these “green” ceramics undergo a heat-treatment (called firing or sintering) to produce a rigid, finished product. Some ceramic products such as electrical insulators, dinnerware and tile may then undergo a glazing process. Some ceramics for advanced applications may undergo a machining and/or polishing step in order meet specific engineering design criteria.

[Zamfir]

If anyone has a used set of Micro fine ceramics they would like to sell cheap please let me know.

I would like to do some experimenting with these as well.

Thanks!
Eric

[CliffCurry]

This video was taken of my Spyderco Endura I was using as a mule for ceramic testing the other day. The dps is somewhere around 12 and the edge bevel is massive, around 2mm from top to bottom.

Obviously there are several deep scratches remaining…left overs from the side by side ceramics comparision. I decided to leave them there for a reference mark on the blade as I explored the realm of using lapping films for the first time to achieve a mirror finish. Man was I surprised! The initial results were excellent & consistent which is what I would expect when replacing worn strips with brand new ones at each micron/grit level.

To me the clearest advantage was not having to worry about rounding the apex, cross contamination, and the other issues that one must me careful of in a multi stage stropping progression. I sometime wonder why we dont hear about sandpaper strips & films more often as they work so well, require little effort, and are so affordable?

Note: The wispy scratches going bottom left to upper right are from .5u diamond spray on new kangaroo strops. I did 10-20 whisper light passes and those appeared….my bet is a tiny bit of contaminate got on my strop.

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