[Zumba]

Here's a piece of E/S (epoxy sand) that came out of a cup. The epoxy conformed to the little seam on the side of the cup (2nd pic) so I guess it picks up details pretty well.

Materials:
West System 105 epoxy with FAST hardener (I had a ton of this stuff from previous projects)
Natural Sand from Home Despot
Cup
Stick

Ratio by volume was about 1:4 epoxy to sand. I probably could've used more sand. I need to find a scale that is sensitive enough to display ounces so I can get exact weight readings.

The color of the final product is kind of a puke/diarrhea mix. I've got a cup of blue mix curing as we speak.

However, texturewise, it's much more aethetically pleasing than mixes with larger aggregate, so I guess the key is to pour the "gelcoat" layer as previously discussed using a mix without large aggregate.

[walter]

Zumba, that looks pretty good!

(btw, here's more info on E/Q...)

Quartz Engineered Stone Countertop Surfaces



The manufacturing process of engineered stone started about 45 years ago in the research facilities of Breton Stone, according to Steve Chambless, co-owner of the local Silestone fabrication and distribution facility in Lewisville.

“It’s all Breton Stone—they got the process down pretty good about 30 years ago, but really perfected it about 20 years ago,” Chambless said. Brenton Stone then sold franchises and product manufacturing equipment (which cost from $25 to $35 million-dollars). About 15 years ago, Coesntino, a 120 year-old-marble and granite-company in Spain began manufacturing the stone, and today Coesntino still supplies white marble and granite as well as the engineered quartz product called Silestone.

About two years ago, Dupont began manufacturing engineered quartz out of Canada. The Dupont product is called Zodiac, which sells for $75-$100 per square foot compared to Silestone at $45-$75 per square foot, according to the Good Housekeeping. Despite the difference in price, both products are produced by the same formula franchised from Brenton Stone.

“The only thing that changes is the quality of raw goods or colors of raw goods, Chambless said. “The percentage of quartz to pigments, resins, binders, has to stay the same, and it does. The hardness of the material is the same. The look of the material is what changes with the percentage of color on a gradient that is put in—not the type. It is still quartz.”

Engineered quartz surfaces do not require sealing because of the resins in the raw ingredients, which make it impenetrable, and the manufacturing process.

Resins, binder, and pigments make up 7% of the product along with 93% purified quartz. Manufacturing quartz begins with the raw white quartz or clear quartz cut out of the mountains. First, the quartz is purified, ground up, and mixed with large quartz particulates—some dime size, some smaller and made into a slab. Through a process of vibration and vacuuming out all air inside the slab, (called vibrocompaction) a 4 and ½ inch slab of engineered quarts can be vibrocompacted down to a ¾ inch slab. After the slab is heated to 180 degrees centigrade, it is polished to a high shine by drums with small diamond bits that act like sandpaper—a process, by the way, that is the same for polishing a granite slab.

(by Dr. Oneida Cramer)

[jsage]

sposi,

Just kidding around. I always find that site useful though. Vaguely remembered robot derived from slavic derivative. Indo Europeans languages, pretty broad group.

Walter,

very nice on the pic, the non consumable looks pretty good too.

On the article I'm still curious about the vibratory frequency. Seems like we had some contradictory findings previously. I believe at a certain frequency (high) the vibration works against getting a good distribution.

Still wondering what grade of epoxy or otherwise they are using. My experience from fly tying, rod building etc, the faster the cure the more prone to yellowing and deterioration. There are also post cured resins which require heat as mentioned. System three has an example. http://www.systemthree.com/p_phase_two.asp . Not to say this formulation is appropriate. More expensive I believe.

Damn, learned metric in elementary but still struggle with visualizing metric scales. I would love to convert, but then I would have to do conversions to communicate to most people.

Excellent article.


Zumba, looking good. What is wrong with puke yellow ; )
Mike

[walter]

On the article I'm still curious about the vibratory frequency. Seems like we had some contradictory findings previously. I believe at a certain frequency (high) the vibration works against getting a good distribution.

I'm trying to chase references and articles but so far, I found nothing. The quote below comes from Italian patent application (describing method of Terastone Technology, which uses cement instead of epoxy):

"...vacuum vibrocompaction of the deaerated layer of mixture by means of application of a vibratory movement with a frequency of 2,000 to 4,800 Hz under a vacuum less intense than 720 mmHg, but not less than 680 mmHg, and for a duration of at least 60 seconds.."

___________________________________________

And here's another take on E/Q:

What is quartz surfacing?

"Quartz surfaces have been around for decades, though the product has only recently gained popularity in the United States. Originally developed as BretonStone about 45 years ago, all quartz surfacing is manufactured in basically the same way — Breton sold the process to other manufacturers such as Cosentino, DuPont, Cambria and CaesarStone.

Quartz surfacing is made from raw quartz crystals. After being mined, the quartz is separated according to size and type, inspected for quality and stored. At the time of production, the quartz and a very small amount of resin and color pigment are mixed until thoroughly combined and then poured into a large tray with a paper liner.

In those instances where two or more colors or types of aggregate are combined to make a color, they are mixed separately with the resin and pigment and combined just before pouring into the mold. Once the mold is filled, it is moved to the vibrocompaction area, where massive presses squeeze the material to roughly half its original thickness. At the same time, a vacuum is applied and the mold vibrated to evacuate the air. Curing is further accelerated by moving the mold with its compressed load into an oven, where it is baked at 100 degrees Celsius for almost half an hour. Then it enters a special chamber where is it air-cooled to room temperature. When it reaches ambient temperature, the product is fully cured and ready for calibration (thicknessing) and polishing. Because of its unique manufacturing process, quartz surfacing possesses qualities not found in other natural, engineered or synthetic materials..."
_________________________________________

[Zumba]

Good info there, Walter.

I'm going to start experimenting with vacuum tomorrow. I've got two Gast rotary vane pumps that I normally use for veneering that can be put to good use. The vacuum chamber will be 6" schedule 40 PVC. I wouldn't trust the stuff under positive pressure, but under vacuum they should be safe. Worst case they implode, rather than explode.

I'm curious as to what the exact purpose of the vibration is. Probably to stir the mix while the vacuum pulls out air bubbles from the surface. Vacuum pressure alone probably isn't enough to pull the air from deeper down in the mix, and it's difficult to physically stir the mix in a vacuum chamber unless you're wearing a space suit.

So I guess the question is, how do you transmit 2000-4000hz frequencies through the mix? The frequency is rather high.... before you posted this, I would've guessed that the frequency would be more like 40-80Hz. I could just tell my friend to bring his 8-speaker bass cabinet and play some jazz licks.

[jsage]

Tetris,

Never really played it but the vibration should should achieve the best alignment of various shaped aggregates. On the other hand high frequencies could sink larger aggregates or prevent them from penetrating as the smaller particle fill more effectively. Not concerned about perfect but adequate processes. Two factors, possible 3. Frequency, duration, amplitude. Examples, mallet, sander, and how long they are used.

Good info Walter.

[Geof]

... On the other hand high frequencies could sink larger aggregates or prevent them from penetrating as the smaller particle fill more effectively....

I think it is possible you have it sort of backwards here. I would expect that low frequencies could excite bulk movement of the constituents of the mix and maybe encourage separation and settling; high frequencies could be expected to cause vibration within the particles promoting release of the air bubbles adhering to the surfaces. Whether the particle tended to move as one unit, the bulk movement, or just vibrate, would depend on the wavelength of the vibration in the mix and this depends on the speed of sound in the mix.

[jsage]

Geof,

Thanks. I was just wondering b/c From concrete work I recollect that larger aggregates will move to the bottom if hit with mallets for too long of period. At the same time, there is a subthread where the large aggregates came to the top when a vibrating sander was used.

Liquefaction from earthquakes. People caught in avalanches. Ultra long landslide runouts ; ) Just trying to relate to this application. Obviously, I am taking a non physics approach and asking the question ; )

Thanks again.

Mike.

[Geof]

Geof,

Thanks. I was just wondering b/c From concrete work I recollect that larger aggregates will move to the bottom if hit with mallets for too long of period. At the same time, there is a subthread where the large aggregates came to the top when a vibrating sander was used.

Liquefaction from earthquakes. People caught in avalanches. Ultra long landslide runouts ; ) Just trying to relate to this application. Obviously, I am taking a non physics approach and asking the question ; )

Thanks again.

Mike.

All low frequency, some ultra-low frequency...except for the ultra long landslide runout.

I have read a couple of proposals for explaining long runouts:
One is that air gets entrained in the rubble and both decreases the bulk density and acts an an air cushion because it can't get squeezed out quickly.

The other explanation, which I favor, is that the particles in the landslide are vibratin; ringing like bells you could say. This means that they do not reside in contact with each other for friction to take effect; they constantly bounce off each other and thus keep running down even a small slope or out onto flat just from their own momentum.

This is not directly applicable to the behaviour of aggregate/epoxy under vibration but is partly why I suspect there would be a frequency dependence because things vibrating internally can behave differently to things that are simply moving in one direction or oscillating as a single unit.

[ger21]

I wouldn't trust the stuff under positive pressure, but under vacuum they should be safe. Worst case they implode, rather than explode.

I still wouldn't want to be standing next to it if it imploded. But, I've been using the 4" PVC ala www.joewoodworker.com with no problems. He says over 200 users have built from his plans, so it should be safe.

Colors look cool.

[Zumba]

Hmmm... the more I think about it, the more weird it seems that they'd want to use such a high frequency. If you mounted a high speed router spindle to your mold and spun an eccentric weight at 20000RPM, you'd still only get a vibration of 333 Hz.

I've got a 5hp induction motor lying around.... maybe I'll mount an eccentric disc to the shaft to give me a vibratory frequency of 60Hz. Think that'll be enough?

[Zumba]

I was thinking that the tetris thing should be done on the aggregate BEFORE the epoxy is added to the mix. Once the epoxy is added, expecially at a 1:10 weight ratio (or 1:14 in the case of the Silestone/Zodiac), the high viscosity would probably prevent any significant shifting of the aggregate. At that point, all you can do is get rid of the air bubbles.

Besides... lets say you had an E/G mixture with the perfect viscosity at the time of pouring. Then somehow, using vibration, all the aggregate fit together perfectly and sank to the bottom. Wouldn't you end up with a pool of empty epoxy at the top?

I'll let you guys figure that one out...

In the meantime, here are some colored blocks for your visual enjoyment. Now that we know what we can expect in terms of aesthetics (the most important part), we can concentrate on the less important stuff like structural integrity. :rainfro: :rainfro:

This time the epoxy to sand ratio was 1:5 by volume. Just like before, it was a medium viscosity West System epoxy. I think a thin epoxy would allow for even more aggregate, as would the addition of larger aggregate (high volume, low surface area). The coloring is Transfast powdered water/alcohol-soluble dye that I bought at the local Woodcraft a year ago. A little went a long way... the amount of blue powder that went into the test block fit on a 1cm section of toothpick.

As you can see from the second pic, "self leveling" ain't gonna happen unless you have vibration and vacuum. Bubbles galore!

And you can probably tell that I screwed up on the top left test block. I used a different type of cup and apparently the bottom didn't have a very thick coating of wax. Stuck for life!

[martinw]

I was thinking that the tetris thing should be done on the aggregate BEFORE the epoxy is added to the mix. Once the epoxy is added, expecially at a 1:10 weight ratio (or 1:14 in the case of the Silestone/Zodiac), the high viscosity would probably prevent any significant shifting of the aggregate. At that point, all you can do is get rid of the air bubbles.

Besides... lets say you had an E/G mixture with the perfect viscosity at the time of pouring. Then somehow, using vibration, all the aggregate fit together perfectly and sank to the bottom. Wouldn't you end up with a pool of empty epoxy at the top?

Dear Zumba,

I've been puzzling over the rates at which different sized particles of the same density will settle in a fluid. For example, if you put a fine sand/pebble/water mix in a bucket and stirred it up, as soon as you stop stirring, the pebbles go to the bottom almost instantly, while the sand stays in suspension for a lot longer. Eventally,however, you will have pure water at the top. I think that this is because a sand particle has a larger surface area to volume ratio than the pebbles, and therefore there is greater friction which slows its sinking. I guess that with an epoxy mix, the thing to aim for is an epoxy viscosity that is sufficiently great to slow this sinking effect, so that it sets before appreciable sedimentation occurs.

I may be entirely wrong and I may be stating the obvious. If so apologies.

By the way, I am not in a position to comment on the beauty of your samples for the reason stated previously.

Best wishes


Martin

[RogerH]

We have a couple of machines with cast bases where I work and they are very rigid.

I designed a machine several years ago that was to have a cast base. I never built the machine but I did a lot of research based on information by a company that exibited at the IMTS show in Chicago. I think the campany was ITW Philadelphia. The company appears to be called Chockfast now and sells products for machine foundations and other uses that might be good for machine bases. They used to sell a product intedned for casting machine bases. They have distributers in Europe.

I was going to use granite surface plates as parts of the mold to cast important flat surfaces. The surface plates would still be available for other uses after the base was cast.

http://www.chockfastgrout.com/indextwo.html

[jsage]

Zumba,

Very nice.

I think with the higher end process of post cure or the process of calorific absorption will suck in the excess. I boat building you get fiberglass pattern showing through when you use dark colors bringing the temp over 140 which draws in the epoxy (calorific absorption). Problem with deep colors like black. Obviously just discussing a concept. Heard it first hand from a chemical engineer involved in boat building. Not a common concept.

I also vaguely remember that it might be better to have temps increasing to constant rather than the opposite, decreasing.

mike

[walter]

The beauty is definitely there, Martin! Oh, just look at the blue one..

EDIT:
Zumba, here's a puzzling picture (ITW Polymer Castings/Zanite):



They seem to be pouring it into a mold. Very dry mix.. I think epoxy is in there already?
...

[martinw]

The beauty is definitely there, Martin! Oh, just look at the blue one..

Dear Walter,

Alas, there is no Smilie for "contemptuous snort"....

Best wishes

Martin

[walter]

From ITW:

About Zanite®
What is Zanite® polymer composite?

"Zanite® polymer composite is a formulated composite material designed for casting machine bases and other structural components. It is a combination of epoxy, quartz aggregate and selected additives..."
...

[jsage]

Zumba,

Again great work, took a closer look. Walter thanks for pounding the pavement or Epoxy Composite. I like that DIY VAC unit.

[djshop]

I am just jumping into this discussion. I skimmed many of the posts but there are 50+ pages! I have a CMS lathe built by upgrade technologies that has a cast polymer structure. I am working on a new purpose-built CNC lathe and was contemplating a composite base either molded or filled structural weldment. If I was to go the mold and casting route, is the composite structure machinable/grindable? What is the thought process for attaching linear rails and headstock? do you cast in inserts and then machine pads for the rails? Or do you use grout to level them?
I am on about a 6-9 month timeframe for this project. I plan to work out the basic controls on a converted Hardinge lathe and then transfer components to the new base.
This is a great site.
Dave