FreeShip- Ceramic Vibratory Media, 1/4"x 3/8", ACT, SiC Probable, With Coating - (Prompt rebate on orders with 3 or more FreeShip items!)

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Note: This media is intended to be run in a vibratory finisher or some other high energy mass finishing machine. It will not perform well (unless you're very patient) in rotary tumblers.
If you're a novice, be aware that vibratory finishing is as much art as science. That goes for nutshell, ceramic or plastic media, and others. The surface of the parts you're finishing, the part material, the media, the machine you're using, etc, are all variables that must balance. If one variable is not in tune, the high polish you're after might elude you. Expect a certain amount of experimentation.

Please note there are 2 listings for this media. This one is for the media that still has some (or most) of the outer light color coating remaining over the black/dark gray "interior". Some pieces will have more or less of the interior black/dark gray showing through where the light colored outer coating has worn away. The outer coating is likely a fused aluminum oxide grit and alumina binder. This media can be run wet with some parts, or just by themselves with a soap/cutting compound to wear away all of the light colored coating. I'm around 95% sure the black interior that makes up most of this media is Silicon Carbide (SiC). 95% because I can't find a record of it's source although I found "silicon carbide" mentioned in my notes from that time. I'm describing it as "probable SiC" and rather than use that long phrase throughout this description, I'm using the shorter "SiC" with the "probable" implied in front of all references to "SiC" or "silicon carbide".

The specs for this ceramic vibratory media:
Shape: Angle Cut Triangle (ACT)
Size: 1/4" x 3/8" (thickness and length of one side)
Cut (aggressiveness): Comparable to "MC" or "FC" with coating, for coloring/polishing without coating
Color: Light Tan Thin Outer Coating remaining to various degrees, Black inside
Condition: 3 to 5% wear. This is almost "pre-broken-in" media which has been used and has abrasive particles exposed. There is still patches of the light colored coating remaining. Complete break-in may occur in a short time after you've run some parts intended for light cutting and then polish. Or, if you would prefer to remove all the coating, refer to the paragraph above. If you proceed to use it as is, it can be used to cut parts until the coating is gone. When the outer light colored coating is worn away it is hard and long wearing.

This is a silicon carbide (SiC) ceramic media, which has at least some (or most) of a thin outer fused aluminum oxide grit and alumina binder coating still remaining but partly worn away. When the coating is worn away, exposing the interior SiC, it will impregnate a hard black/gray SiC finish on polished grade 5 titanium and possibly to other hard metals. It does this by forcing microscopic SiC particles into the surface of the titanium. This can happen with other very hard media as well. "Impregnating" is the term often used to describe how the coating is forced onto the metal surface. It's usually an unwanted condition but in this case I consider it a "value-added" step.

The pictures show:
1st picture)-- The standard quantities available (400 gr (~0.88 lb), 908 gr (2 lbs), and 1816 gr (4 lbs).

2nd picture)-- This shows a single piece of the new media, which has been cleanly cut with a thin diamond cutting disc into 2 pieces. It is dry, so the black interior shows up as gray. When burnished or when wet it shows up as black/dark gray.

3rd picture)-- This show the grade 5 titanium after it's polished, and after being run in the burnished, shiny black media shown in the top row of the 2nd picture. It's shown in a shallow teflon-coated pan with lighting
placed to show how the dark coating on the titanium looks different with different angles of light. The flat,
smooth pieces reflect almost all light and thus look "silvery". The thick cylinders look black on their sides
(as do the large thin hoops) with a silvery highlight on their top surfaces. The textured flat pieces look
black, dark gray, with silvery highlights. The textured flat pieces were made from the thick cylinders by
heating one to a bright red on the end of a sturdy 2" diameter axle acting as an anvil that had a negative
surface cut by carbide burrs. The red hot cylinders were placed onto the negative surface of the anvil and
hit with a heavy hammer showing the positive version of the carbide burr cuts made on the anvil. They
were forged, in other words.

4th picture)-- This combines the previous picture of the mass of dark polished titanium, along with a view of a row of completely burnished SiC media at the top. It shows the sizes along with a different background for the titanium and how it varies in color.

5th picture)-- All stages of wear of the media:
The top row shows the media with the light colored thin coating completely worn away and the black/dark gray "interior" of the burnished (shiny) media.
Below the top row are 5 piles of the media showing:
'a' pile)-- (on the far left) the new media with the light colored thin coating still intact.
'b' pile)-- shows the media after it's been used for a while; the edges of the media wear away first which is
why you see the underlying black interior there. This has been run wet. How fast it wears away is
dependant on the vibratory finisher, the soap/cutting compound, and the hardness of the material of the
parts.
'c' pile)-- shows the light colored coating almost completely worn away. It was also run wet at that stage.
'd' pile)-- shows the light colored coating completely worn away, with the media now burnished (it's run
wet until the coating is completely gone, then it's run dry to achieve the burnished finish).
'e')-- shows a single piece of the new media, which has been cleanly cut with a thin diamond cutting
disc into 2 pieces. It is wet to bring out the color so you can more easily see the contrast between the thin
light outer coating and the black interior. The coating appears more tan when wet. The rest of the pieces
are shown dry. You can see the tannish color in the fully coated pieces, it's just lighter when dry.

6th picture)-- Shows what the a group of the SiC burnished media (after the light colored coating has been completely worn away) on the left side. It is the media which darkened the polished group of grade 5 titanium pieces on the right.

Note that this top section describes the coated SiC ceramic media specifically. If you want more info on vibratory finishing go to the 2nd section below the dashed line.
This non-traditional, "sintered-like", probable silicon carbide vibratory media is rare and perhaps impossible to find anymore, especially with an alumina coating over the interior SiC . There are several versions of alumina (Al2O3, aluminum oxide). Most ceramic and plastic media have some form of aluminum oxide as the abrasive grit and/or polishing agent ingredient (see below, there is: "fused aluminum oxide", "fused white aluminum oxide", or "calcined aluminum oxide"; the word "alumina" may be substituted for "aluminum oxide").
Silicon carbide (SiC) traditional ceramic media is uncommon but can be found. There is a source for a plastic media that uses a urethane binder with only SiC grit as the abrasive particles (it is quite expensive), and several sources for traditional ceramic media that uses SiC grit with a traditional light colored ceramic binder. It appears as dark speckles on a light colored background.
The most common reason for using SiC as an abrasive particle is that it will not contaminate the surface of metal parts with aluminum oxide, which gets in the way of welding or soldering that metal, and is also not compatible with human tissue when that metal is used in the body as is titanium for bone repair. More on that is in the 2nd section, below.
To date our shop is the only source for this very unusual, non-traditional ceramic media (I haven't found more of it yet) which has perhaps 95% to 92% silicon carbide along with about 2% to 5% of alumina (depending on the size of media) as a coating over the SiC interior. We have 2 listings for this media which are the same basic media at different stages of wear. One is a listing for the media which still has most or some alumina coating and another media listing which has all or most of it's alumina coating worn away and has been burnished (in this context "glazed", polished, or shiny) to serve as a polishing media with a twist.
The "twist" is that it will put a black/dark gray silicon carbide coating over polished grade 5 titanium. I haven't tested it with other hard metals. It's very possible it will also black coat polished stainless steel, nickel, chromium, etc. This listing is the 1st one, it has mostly some thickness of the light colored coating remaining over the almost all black/dark gray silicon carbide interior.
In the pictures you will see the various appearances of this media, pieces of which are still entirely coated with a light color alumina, some pieces that have about half light color alumina left, and some pieces which are nearly all black/dark gray.

Our ceramic media was purchased about 7 years ago. I know the companies where I got all of it, except for this. I've already contacted all the companies I dealt with asking if they carried or had carried anything like it. None of them had. I think it's most likely that I purchased on ebay, and I thought it was just a run of the mill aluminum oxide media, because with the outer layer of Al2O3, that's what it looks like. Probably that's what the seller thought it was, too.
Why is it coated? One speculation is that it was an "R&D" media, made for testing the idea of having a single media that would do the initial abrasion faster (the light color Al2O3) and when worn away the SiC would do some initial abrasion that would remove any aluminum oxide (Al2O3) "contamination" just before the SiC became burnished and started polishing.
Other theories? Perhaps someone was testing an easier process to make a silicon carbide "sintered" media without going to the expense of actually sintering it, the coating somehow contributing to the process. Most of the tech people I talked to and whom saw the pictures of the media progressing from a light tan color to a solid black and saw the cut-in-two picture, both didn't have and had never heard of a coated ceramic media. One expert refused to believe the sectioned piece showing the light color, thin coating, with the inner solid black structure. He swore that the solid black pieces were just a coated-with-abrasive-dirt media over an underlying normal light colored alumina interior (exactly the opposite!). Such a thing can happen with a media designed to run wet and that is allowed to dry out. It will coat itself with vibratory machine process dirt and end up looking a different color, but not with such an even surface as the polished solid black/gray media pieces shown in the pictures.

When I discovered the media turned black after a certain amount of wear I started testing the best ways to use it. I ran it wet when new with the coating still on it and it abraded (vibratory lingo for abrasion or abrasive is "cut") about the same as a medium "cut" media. When the light color alumina was worn off, the cutting action decreased quite a bit. I took a cue from the all white non-abrasive porcelain media I was using for polishing, and tried running it dry (I get a faster polish on grade 5 titanium running porcelain media dry). The result was the dark color polish. I also found that if the titanium was already polished or nearly polished with porcelain media, the dark coloring would take a shorter time.
Most media is designed to be run wet. Media that will run successfully dry needs to be very hard so it will create minimal dust and wear very slowly. Non-abrasive porcelain fits that requirement and so does the dark SiC (a little less so than the porcelain). I've run both of those for a week and had no problems with excessive built up dust. Every once in a while it might have to be cleaned. With the porcelain, running it wet with a non-cutting soap solution cleans it. That also works for the SiC. It's faster if you add some porcelain media with the SiC.

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This section describes vibratory ceramic media used in a vibratory finisher in general. The above section describes SiC media.
The ceramic media we have was mostly for an initial heavy cutting, then to medium cutting, then to polishing of small titanium "chunks" consisting of disks, rods, and irregularly shaped forged pieces. We also used it for rocks and minerals in sizes from 1 to 2 inches up to 8 inches in the same heavy cutting to polishing steps of the titanium.
Ceramic media is just one type of media that can be used in vibratory finishing. Ceramic media probably holds first place in media used if you include industrial usage. Other medias are exotic "ceramic" media made with higher temperatures, stainless steel shaped media, hard nut shells (usually walnut) charged with a cutting or polishing compound, and corn cob or other soft media carriers. Simply do a google search on the phrase "ceramic vibratory media" and you will come up with many suppliers and manufacturers of ceramic and other types of vibratory media, as well as educational info on the codes for ceramic types, and ceramic shapes ("ACT" = Angle Cut Triangles, "ACC" = Angle Cut Cylinders, "ACE" = Angle Cut Ellipse, etc.)
The titanium pieces we were finishing required some heavy duty media because of grade 5 titanium's hardness and toughness. Most types of rocks we finished were igneous or metamorphic, harder and tougher than titanium. So, most of the media we have is ceramic media, and a lot of that is the very heavy cutting brown "DF" media.

Here is a supplier who sells ceramic and plastic media and gives their code types with descriptions (unfortunately, code names vary from supplier to supplier):
http://vibratoryfinishers.com/tumblingmedia.htm
Below is a good site for viewing photographs of actual media and doing visual comparisons. Click on "Tumbling Media" and the type of media you want to see. Of course these pictures are only of the media this particular company sells. The plastic and ceramic media from other manufacturers can have different code abbreviations and will look differently. And even the exact same media code from the same supplier can vary in color, because what they buy from the manufacturer depends on the materials the manufacturer has and how closely they stick to the same formula (quality control). Here is that link:
https://cmtopline.com/

The "cutting" action of ceramic media comes from the abrasive particles that are mixed throughout the ceramic matrix before it gets fired in a kiln and hardened. There are several types of abrasives (aluminum oxide being the main one) and many formulations that vary by clay types, abrasive types, and the temperature the "clay" matrix is fired at in a kiln (to become "ceramic" media).
The variables in types of media are the composition and mesh size of the abrasive particles, the amount of abrasive particles in the ceramic matrix, the type and hardness of the ceramic matrix, the shape of the media, the size of the media, and the weight of the media (heavier media pieces cut faster).
Almost all ceramic media needs a "break-in" period when new. The abrasive particles are not yet exposed because the ceramic matrix (originally clay before firing) is covering them on the outer surface. They need to be run with some loose abrasive grit, or some media which is already broken in. Or they can be run in a vibrator with no additives, just the new media rubbing and hitting against itself. The time it takes to expose the embedded abrasive particles varies with the type of media. Even "porcelain" media which has no abrasive particles needs a break-in period (to become shiny and "glazed" so it will polish).
What that break-in period causes is a certain time that's wasted; non-productive time (wear) on the vibratory machines. Even mixing new, non broken-in media mixed with used, broken-in media in a batch running parts will take more time to finish because only part of the media is cutting (the used media).
So, buying used media that's already "broken in" is actually more economical than buying new media because there's no need for a break-in period. There is no difference in the cutting action of the media as it wears down over time, except that it becomes smaller and it's true that media pieces that are larger are heavier and so hit the parts being finished harder, but you could also argue that in the progression of finishing, you want a smaller impact against the parts, you want a gentler cutting action as the finish becomes smoother. You will need to add more media to keep the mass in the bowl up to a certain height. On a weight basis alone, the cost of new vs used media is exactly the same.
There are a lot of variables in choosing the type of ceramic media at any one stage of finishing your parts. The main factors are the material the parts are made of and the size and shape of your parts. Are they all curves? Or do they have flat places? How large are your parts? Larger parts usually call for larger media size.
Another factor in choosing which media to use is the part final surface you want to achieve. If you want a high polish you will want to use a non-abrasive media or walnut shells charged with a very light cutting/polishing compound (and if the part surfaces start out rough, you'll first need to use 1 or 2 successively finer cutting medias). If you just need a smooth matte surface or if you just need to deburr, you may be able to use just 1 step (depending of the initial condition of the parts). If your "parts" are stone you will probably be wanting a high polish, which will require a sequence of the heaviest cutting media to start with. That will take the longest time and so you will need more of that media than the medium or light cutting media. If your parts are a soft metal, like aluminum, silver, or gold, you'll need a milder cutting and finer abrasive media, something gentler and lighter weight. Walnut shells, again, may be a good choice.

Ceramic media is designed to run wet, with some exceptions (polishing can work well dry if the parts are close to a polished state and the media is very hard). Running some types of cutting medias dry is possible if the parts don't require a lot of time and you alternate dry with wet cycles. Running dry can cause a "glazed" (shiny) media surface. Glazing is only good when polishing (you want porcelain polishing media to be shiny; if not, it won't polish). But with a cutting media, cutting action with glazed cutting media is nil. The cure is to run the cutting media alone, wet, and with some fine loose abrasive added.
Some people add a fine loose abrasive with the ceramic media for every batch of parts they cut. The weight of the media acts as a "driver" for the loose abrasive so it will abrade against the parts with more force and more abrasive particles cutting the parts and thus speed up the finishing process. This also has the effect of keeping the ceramic media surface "sharp" and helps prevent glazing on media which is supposed to cut. The flip side is it tends to wear the media down faster. Some people also use non-abrasive porcelain as the "driving" media in concert with the fine loose abrasive abrading the parts, because porcelain media is so long lasting.

Running ceramic cutting media creates a fine waste byproduct consisting of metal from the parts and fine ceramic and abrasive particles. If the vibratory machine is allowed tot become dry or almost dry this will become compressed as a layer of grunge against either the parts, media, or both. It will "gunk" up the process until no further cutting is possible. The machine bowl must be run wet so the waste byproduct is mobilized as a loose slurry which doesn't appreciably slow further cutting. In a "closed" system the slurry will still eventually turn to slush, paste, and again, "gunk" up the process. That can be delayed by removing the lid and observing the movement inside the bowl. When it slows down, the addition of a little more water will extend the length of time the finishing process can continue. The goal will be to get the parts to a finished state before having to clean or "de-gunk" the bowl and media. After some experience you will be able to make judgements just by the change in sound of the media moving in the bowl, without having to remove the lid.

There are two main ways of dealing with waste in a wet process: a "closed system" approach, mentioned above, or a "flow-through" approach. Fairly self explanatory, the flow through system feeds a trickle of water (how much depends on the bowl size) through a fitting at the top side of the machine bowl and drains through a fitting on the bottom of the machine bowl.
The closed system approach relies on said observation of the media (visually or by sound). When the slurry is too thick there are several options. Dumping the batch into an external container and flushing it and the inside of the machine bowl clean is the most radical. Alternatives are several. What worked best for me was to make a "wand" of thin pipe with a nozzle to immerse in the running machine bowl and thereby flow fresh water in with one hand. The other hand will hold a similar wand immersed in the bowl sucking water out with a pump. After a time, the thick slurry will be flushed out completely and replaced with clean water. Then more vibratory compound or whatever "soap" you like can be added to the water in the bowl. It should not have too much water; a sign you have way too much is if any at all splashes upward around the center of the "donut" of the bowl).
The method chosen also depends on the size of the vibratory finisher, of course. My method worked great on my 17", 5 gallon finishers and less well on my 10", 3 qt finisher.
The flow through system greatly discourages the use of vibratory cutting compound which is expensive. A flow through setup used with vibratory compound is like throwing money down the drain. But vibratory compound really works. If you chose a closed wet system, it's use makes sense. About 1 part compound to 64 parts water is a typical ratio. Because of it's expense people have tried all kinds of less expensive compounds: Murphy's oil soap, borax, oxalic acid, dishwasher detergent+ammonia, etc. I've tried plenty of things myself. Any kind of soap fits the bill nicely, but it needs to be a non-foaming soap. Excess foam slows the cutting process.

Vibratory finishing has been around a long time now. An exact date is difficult to say but it probably began in the mid 1950's and took hold in the 1960's. It uses the same principles as rotary rock tumblers used by hobby rock collectors (popular with kids in the 50's, 60's, and onwards). The weight of the rocks constantly tumbling against each other with abrasive between them through successively finer abrasive stages for several weeks (or months) ended up with highly polished rock specimens.
Vibratory finishing is similar in that it rubs and hits parts together with an abrasive media under constant movement. But the difference is it does so with many times more speed and energy. Vibration is several orders of magnitude higher in energy than with a rotary tumbler. It can be adapted to very fast "cutting" for layers of oxide removal, to deburring, to simple smoothing, to high polishing. The strength of vibration can be varied with relative ease so that one machine can be put to multiple uses. It's used in everything from finishing large castings in industry, or by jewelry makers for light smoothing and polishing of soft metals.

If your goal is heavy cutting you will be needing a fast cutting media. The variables for speed of cutting have been mentioned above. Also the hardness of the ceramic matrix. And the total weight of the media pieces. Of course the machine matters, too. The cutting speed is quite dependant on the energy (intensity of vibration) put out by the machine.
Weight is very important. If the media is heavy it impacts harder against the parts. The weight of the various ceramic media formulations can vary from 60 to 130 lbs per cubic foot. Usually though, there will be a range of weights listed for each type of media (size matters: larger media has more space between pieces than smaller media, so a cubic foot will weigh less for large sizes and more for small sizes).
The clay binder used (which becomes the ceramic matrix) and its firing temperature will also affect the media's speed of cut, with a softer post fired ceramic matrix wearing away faster and exposing more fresh abrasive particles and therefore cutting faster (the flip side of that being you will have to buy media more often). Ceramic media can vary from 45 rockwell (rockwell is a measure of hardness) to a harder 65 rockwell.
The size of abrasive particles is usually in the 80 to 220 mesh range. Finer mesh sizes may be used for light cutting or pre-polishing. The coarser meshes will cut faster than the finer ones but will leave a rougher surface. The amount of abrasive particles in a media will also influence how fast it cuts.

As mentioned above, the major abrasive used is "aluminum oxide" (Al2O3).
But aluminum oxide is a loose term. If you want to be more accurate, the type of aluminum oxide can be specified. It can be: 1) "fused aluminum oxide", 2) "fused white aluminum oxide", or 3) "calcined aluminum oxide" (or some combination of words that have "alumina" substituted for "aluminum oxide"). Fused aluminum oxide is the one that cuts and is usually dark colored. Fused white aluminum oxide is a white Al2O3 that also cuts but is less common. Number 3 is used as part of the binder, or as the major ingredient in "porcelain" media, which does not usually cut, it only polishes to the degree that it's polished.
In the real world vernacular, "aluminum oxide" will usually refer to the dark Al2O3 that cuts (fused aluminum oxide). The term "alumina" will usually refer to the white Al2O3 that does not cut, has been calcined, and is associated with refractory applications. This one varies most in terminology. You will see it as just "alumina", "alumina oxide", "calcined alumina", "calcined alumina oxide", "calcined aluminum oxide", and possibly others. Adding to the confusion of which "Al2O3, aluminun oxide" you're dealing with, is the fact that the above terminology and meanings can be mixed depending on who is describing a kind of Al2O3, and what they've used it for.

Aluminum oxide and alumina are chemically the same, Al2O3. But as described above there are different kinds of aluminum oxide (or alumina). Porcelain ceramic media is comprised of high fired and (hopefully) high purity white alumina. Fused aluminum oxide is made by mixing it with iron in an electric arc furnace and taking it to very high temperatures. It comes out a brown/black color and is crushed to make tough (fused) "aluminum oxide" abrasive particles. Porcelain ceramic media is too brittle to be used as a crushed abrasive although technically it too, is still "aluminum oxide", but the word "alumina" is used to describe it.
For some applications, metal parts that have been finished by vibratory machines (or any other method) using a ceramic media that contains fused aluminum oxide can be "contaminated" by impregnation of particles of fused aluminum oxide that have been forced into the surface of a part (impregnation). Metal parts made of titanium (which is inert and can be used inside a human body) that have small amounts of fused aluminum oxide particles exposed can cause compatibility problems with human tissue, since fused aluminum oxide is not inert. Other metals that have fused aluminum oxide contamination can cause problems. For example if they are welded, brazed, or soldered at a contaminated area the joint will be much weaker.
Awareness of the possibility of fused aluminum oxide contamination for sensitive parts can lead to the choice of using a silicon carbide abrasive in the ceramic media. As mentioned above silicon carbide ceramic media exists. Silicon carbide ceramic media does not have the contamination problem that fused aluminum oxide has. Silicon carbide is definitely a blackish material. A pile of pure silicon carbide abrasive particles will look black/dark gray with variable shininess. A pile of pure fused aluminum oxide abrasive particles will look light to dark brown to almost black. Silicon carbide is slightly harder (mohs 9.5) than fused aluminum oxide (mohs 9.0). Diamond, the hardest material, is mohs 10.

Usually, a part that has gone through an overall cutting process by aggressive heavy cut media, will require a second cutting with a milder media to achieve a smooth, scratch-free surface. This can be accomplished by using either an "MC" or "FC" (Medium Cut and Fast Cut) which, despite the names, I've found to be pretty close together in real world results. Both will achieve a smooth surface with the "FC" cutting somewhat faster than the "MC".
If a polished (or "bright") surface is required for the parts, a burnishing ceramic media is used. This is the porcelain media mentioned above that contains only a very hard porcelain ("fused white aluminum oxide", or "calcined aluminum oxide") with no "fused aluminum oxide" abrasive particles at all.
As your ceramic media wears down and becomes smaller, you will need a strategy for dealing with different sizes of the same media. Most people add more of the same media (some that's new and larger than the worn media) into the vibratory bowl with the smaller media. Sooner or later the smaller media becomes so small that it can become "lodged" (stuck) in holes/concavities in your parts.
At that point, with a closed system, you will need to pour the media on a screen put over a bucket which allows the small pieces to fall into the bucket. What's left on top of the screen will be larger (but still smaller than new). With a flow through system, the tendency is to not go to the bother of dumping the bowl and cleaning it since (in theory) the bowl and media stay clean. This can lead to more smaller size media pieces that with a closed system with screened sizing.
In the real world however, a universal problem with flow through systems is clogging of small media pieces; no matter what sizing method you use, the drain seems to inevitably get clogged with some stray small pieces. I was never successful at getting a long term flow through system to work reliably. If not watched regularly, the drain will get plugged up, the water continues to flow into the bowl and floods it, stopping the cutting action and leaking water through any gaps in the lid/bowl. If you make sure to always use large, relatively new media in a flow through system, it has a better chance at succeeding.
Another strategy is to remove the media when it becomes a certain slightly smaller size and store it. If you finish different sized parts, you can then bring out the smaller media and use it for the smaller sized parts in a smaller sized machine. I've done this and kept about 3 or 4 step sizes of worn, smaller sized media. You have to collect enough of each size to have enough to fill the machine to a certain level, of course.

How full do you fill a vibratory finishing machine's bowl? Not all the way to the top is the generally correct answer. I've read that it should be anywhere from 1/2 full to 3/4+ full. I think 5/8 is a happy medium. With vibratory machines, the first thing that usually goes bad (if you have a thick bowl that doesn't wear out first) is the bearings in the motor that has off-center weights on its shaft that create the vibrations. Those weights are how you adjust the intensity/energy of the vibration. Usually every machine will have a mechanism for moving those off-center weights towards the center, which decreases vibration and finishing speed, but increases motor/bearing life. If the weights are moved more off-center than where they were when the machine was purchased you'll increase vibratory energy but decrease motor/bearing life. If you're handy you can remove the motor and replace the worn bearings, getting more life out of your machine. Of course if you're not mechanically adept, you can also spend more money but less time, and just replace the whole motor.

Last but not least is Wikipedia, which I use so much. Their article on vibratory finishing, though, is short and very generalized:
{ https://en.wikipedia.org/wiki/Vibratory_finishing } :
"Vibratory Finishing
Vibratory finishing is a type of mass finishing manufacturing process used to deburr, radius, descale, burnish, clean, and brighten a large number of relatively small workpieces.
In this batch-type operation, specially shaped pellets of media and the workpieces are placed into the tub of a vibratory tumbler. The tub of the vibratory tumbler and all of its contents are then vibrated. The vibratory action causes the media to rub against the workpieces which yield the desired result. Depending on the application this can be either a dry or wet process.
Unlike rotary tumbling this process can finish internal features, such as holes. It is also quicker and quieter. The process is performed in an open tub so the operator can easily observe if the required finish has been obtained.
Vibratory tumblers have an action that is similar to filing. An eccentric, rotating weight shakes the tub in a circular path, during which the entire load is lifted up at an angle and then dropped. As the load is falling (but not actually airborne) the tub returns to an upward position, applying an upward and angular force that causes a shearing action where the parts and media rub against each other....
Vibratory finishing systems tend to produce a smooth finish because the media essentially laps the parts. Since the load is moving as a unit, very fragile parts are quite safe in the vibrator. There is no tearing action or unequal forces that tend to bend and distort parts. The larger the parts or media are, the faster the cutting action...
The frequency and amplitude of the machine controls the finish of the parts. The frequencies can vary from 900 to 3600 cycles per minute..."
You have to go to Wikipedia's article on "Mass Finishing" to find mention of vibratory media:
{ https://en.wikipedia.org/wiki/Mass_finishing } :
"Preformed ceramic media-
Ceramic media are manufactured by mixing clay-like materials and water with abrasives, forming the mud into shapes, drying the shapes, and firing them at high temperatures to vitrify the binder. Many of these binders are porcelain-like in nature. Variability in these products occur both with the type of binder used, firing temperatures, the amount, size and type of abrasive grains they contain, and their uniformity of firing. This type of media today is the general workhorse of mass finishing systems and is the type of medium generally used, because of its availability in a variety of shapes and sizes, low cost, and low wear rate."-

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Reviews

Reviews (1)

Average:

Jun 14, 2022

Bought this for my rock tumbles! Can't wait to try it out!

Ashley Cheyenne