[walter]

I fired up the mixer and just went for it. Sorry for the poor picture, I had to shoot automatic.

It was great fun- I did it all at once, took about 4 hours total. The whole thing is over 6" deep, 9" wide, 42" long.
_

[ckelloug]

Hi Cameron.
Thanks for the thumbs down on the polycarb. Saves me experimental time

That nanoclay link was a little puzzling as I couldn't work out what Tg represented from the context. They use the term several times but I couldn't crack it.

Tg is the glass transition temperature. It is the temperature at which the set epoxy goes from the solid glassy state to a less solid rubbery state. A higher Tg generally means more stiffness at the temperature it's to be used at.

On the subject of clay and epoxies.
Having carefully washed out any dirt from my original sample of "ballast", my first source of an aggregate, it occurs to me that I was probably washing out all the finest particles of the total mix.
I know that the cement people think that dirt is anathema to a strong mix, so washing out is recommended, but leaving out organic material for the moment, I wonder how you define "dirt", and how does it differ from clay. From my days with pottery clay, I think of it as flat aggregates of silicate particles, and could these particles be a useful part of the total mix that we are seeking ?

The concrete people definitely don't like clay as it messes with their chemistry. Clay in general messes up epoxy rheology but not chemistry from what I've read. I believe that the Nanocor stuff is Titanated which makes it hydophobic and minimizes the rheological effects. The Nanocor stuff is interesting to me because they say that it disperses to nanometer sized particles that create the dispersion hardening effect I was talking about. The zirconates and titanates seem to be miracle chemicals. I've started trying to get samples from one of the niche chemical companies that makes them (and supplies Nanocor).

Mind you, it could be that the clay particles might retain water unless high temperatures were used for the drying process before mixing with the resin, giving further complications.
Ho hum.

Clay does retain moisture unless it is titanated or silyated. From what I've read lately, water on the surface of the particles ruins bonds.

The particle separator continues its development, only the transparent front to add now. Lost a good friend to the big C last week, so progress somewhat slow. The sort of guy that, after you'd seen him, you felt better for it. I shall miss him.

Regards
John

Sorry to hear of the passing of your friend. We all must pause and remember at times like this.

Regards all,

Cameron

[Bob, B.]

This is a bit off topic, however a while back I was, (For no particular reason.), thinking about babbitt bearings. What are they, REALY? A random matrix of hard particles suspended in a soft material. I have no idea if this has been used before, (If not, then I hereby name it BBC, Bobs Babbitt Composite.), and my tests have been limited to polyester resin, drywall screws, welding rods and one ounce mixing cups.

Here it is, wash some steel wool and fix your rod/screw in the wool, in the mold. Pour in the resin and manipulate the wool in such a way as to make sure the steel fibers/resin are well into the threads. For babbitting apps, remove the rod when the mix is still green, and then cut the casing and use the rod itself to force graphite powder into the surface untill it can take no more.

The result is quite stout, machines easily and holds a thread very well. My testing is not scientific in any way, but it passes the, “seems to work really good”, test.

On the bearing surface of your mold, what if you were to first dust it with graphite, and then add a thin layer of steal wool, permeate it with a fine “sand”, then thin epoxy, then fill the rest of your mold with E/G, press and vibrate?

It could also be used to mount bolts and such into voids cast into your main structure for final assembly.

Bob, B.

P.S.
Cameron, condolences for you and your friend.

[brunog]

I fired up the mixer and just went for it. Sorry for the poor picture, I had to shoot automatic.

It was great fun- I did it all at once, took about 4 hours total. The whole thing is over 6" deep, 9" wide.
_

Nice work Walter!

Tell us more, How did your vibrating motors work out?

looking forward to see the unmoulded piece:cheers:

Best regards

Bruno

[walter]

Thanks!

The motors worked well, but I wouldn't use them on larger molds. Vibrocompaction seems to be the most important issue and it does remove air bubbles, so you need to make sure you've got enough firepower. My motors are 4 Amps 250W 220lbs of force and did ok for 100 lb mold. Anything above 200lbs needs more power. Also, your mixer needs to be fairly strong and you really have to rehearse the whole thing and work out the logistics. I've done 60lbs of samples, I'm familiar with the mechanics- it was a fun job. For novice user I recommend enlisting the help of a friend.

The mixer is very important, it needs to do the job while you're doing other stuff. I recommend the stationary pizza type mixer (picture)- hopefully you can find a junked one. For continuous work 2 mixing pots are necessary. I mixed in pots with no liner- don't think liner would work. Metal bucket with lacquer thinner and toilet brush took care of the cleaning.

But really, there is nothing to it.

PS. I went through 100 pairs of nitrile gloves and 7" stack of paper towels!
_

[ckelloug]

Walter,

That's a rather serious mixer!!!

Bob B,

Can you elaborate more on your idea? Are you using the graphite for lubrication? Graphite will likely need to be treated with titanate or zirconate to stick to the epoxy well. Somehow, seeing you post, the metal filled products I saw at http://www.ptm-w.com/ came to mind.

Also for the record, It was actually John (greybeard) who lost his friend this week though I am sure he accepts your condolences just the same.

Cheers and welcome to the E/G Thread, Bob.

Regards all,

Cameron

[walter]

LOL, I wanted to post picture of one of these junk 8qt mixers. This one is more like 80 qt.

[lgalla]

I you cannot afford the dough,for a dough mixer,Buy time on a machine at your local pizza place or dough not shop:Or buy a mud mixer,AKA epoxy mixer and use low speed.300 rpm with a drillpress or 1/2"drill.
Goldblatt Easy Clean Drywall Mud Mixer
Goldblatt Easy Clean Drywall Mud Mixer
ITEM # GB15315
GB15315

# Quick and easy to clean
# Fast, efficient mud mixing
# Rust free, lightweight and durable design for extended life
# Will not shear bucket and contaminate mud
# Patent pending




All-Wall Price: $16.69

[greybeard]

Thanks everyone for your kind thoughts.

Goldblatt Easy Clean Drywall Mud Mixer

# Quick and easy to clean
# Fast, efficient mud mixing
# Rust free, lightweight and durable design for extended life
# Will not shear bucket and contaminate mud
# Patent pending

Larry, I must confess that I thought this was one of your inventions, never having heard of mud mixers. I thought mixing mud was for kids.

Cameron, nano sized zirconates, etc. Are we talking colloidal particles here ?

John

[Bob, B.]

Sorry about the mix up. I didn't realize what I'd done until after I posted, and I was running out the door. None the less, it seems like the Big C is getting more and more people, and it's not a good way to go. My condolences.

The reason for the graphite is strictly for lubrication, in the babbitting role. With polyester resin there's no conflict with the graphite, and it seems to get embedded into the surface. Epoxy would be different, maybe. I haven't tried it yet.

What I've used it in is hard to access/irregular voids, where I needed something to carry a long connecting rod, where heat is not acceptable. The polyester shrinks a bit, and all you have to do is:

Assemble, and get your rod just where you want it.
Pack the area with steel wool.
Create dam with clay.
Pour resin.
While still green, break the bond and disassemble.
Fill with graphite, and work the rod in and out while twisting.
Let cure, add more graphite and reassemble.

It seems more robust then bondo, fiber glass or wood pulp with glue.

For this post, what I'm getting at is incorporating an ACTUAL bearing surface, into the bearing surface. You might be able get the advantages of E/G, as well as a machinable surface. In one monolithic unit.

On the same lines, how about cutting two inch lengths of hard facing rod. Pour epoxy into the bottom of the mold so that when you place the rods on end into the epoxy, it comes about half way up the rods. Then fill with “sand” up to the top of the rods, then top it off with epoxy and then the E/G.

Or, more less the same as the rods, except three or four sizes of ball bearings sized according to the established formula.

The idea is to get a workable surface with more less the same property's as E/G, that transitions into the actual E/G. One of the advantages would be that you wouldn't have to worry too much about a “perfect” mold, because you're going to work it afterwards more less as though it was steel. You wouldn't have to work it much though, because it would be fairly simple to get the mold very close to spec. You could probably cast pads out such a material, lap them, and then place them in the larger mold. This way you might be able get a large E/G machine with a steel surface, without any expansion issues whatsoever.

Personally I think the ball bearings would be the best. Loose bearings are cheep and easy to find, also it would be fairly simple to dump a bunch into the mold and shake it around. Essentially, E/S that turns into E/G.

Bob, B.

[ckelloug]

Hi all,

I've just completed an update to the thread index current to August 1.
http://www.cnczone.com/forums/showpo...22&postcount=8

Hopefully this will make it easier for those just joing us to stay involved. It's the second index post in the index thread. The first is the old one and I could not delete it.

Regards all,

Cameron

[BrendaEM]

For a low-buck mixer, you might be able to use a drill-powered mixing attachment of some kind.

We used to use such an attachment for mixing "Hull and Deck Putty" affectionately known as "Glop" for the sound it made if you dropped some.

[ckelloug]

John,

The nancor clay material once mixed thoroughly becomes colloidal. The particles are on the order of the size of the adhesive molecules. One of their materials says it is specially treated for amine cured epoxies. These materials are specially designed to have the dispersion hardening effect I've been talking about for a long time.

The titanates and zirconates are liquids which like silanes affect the surface chemistry of the aggregates.

Bob B,

Interesting method for bearing surfaces.

BrendaEM,

Weren't you one of the folks in another thread that was trying to figure out how to do machine alignments and posted the interesting stuff from open source instruments? The drill powered mixer is a good idea.

As for me,

I just got samples of titanate and zirconate bonding agents courtesy of Kenrich Petrochemcials. One of them is flammable (contains isopropyl alcohol) so the little tiny sample bottles came sealed in a big plastic bucket in a box with hazmat labels all over it. From my research, these chemicals are the most powerful technology available for improving the bonding of adhesives to just about anything. The zirconates and titanates also greatly lower the viscosity of mixtures of adhesive and tiny particles so even clay which would turn a batch to mud is liquid in the presence of titanates. I believe this is due to the fact that titanates react with hydrogen molecules on the surface of the aggregate drastically lower the number of hydrogen bonds.

--Cameron

[BrendaEM]

[That was me.]

Also, please be careful not to inhale thickening additives such as: microspheres, silica, and colloidal silica.

Additionally, there's something magical about resin that it always yearns for your eyes, so please always wear eye protection.

[From laying up fiberglass, I once pulled off a set of goggles once seeing resin spots, knowing that it could have been my eye.]

Pets such as cats and dogs find resin almost as sweet and deadly as anti-freeze. Working in a semi-industrial area, a neighbor lost her cat, from the shop I worked at.]

[Bob, B.]

ckelloug,

Imagine the pain in the @$$ that cutting and grinding hundreds or thousands of hard facing rods would be. And how relatively easy pouring bearings would be, thats mainly why I've been thinking that bearings would be better. THEN, it occurs to me, how about using roller bearings? It would still be a pain placing them though. Would you be able to just pour epoxy over the top of the rods, and still get acceptable penetration with the “sand”? Would it be necessary to use “sand” to integrate the E/S with the E/G? Some sort of jig? Shake them into a flexible tube so that you could hold the tube over the mold and have the bearings drop upright into the epoxy, as you moved the tube back and forth?

Hopefully someone with steal wool, polyester and epoxy resin will make a sample of both and compare them. I've been curious as to the difference, but I haven't been willing to spend the money on epoxy, not knowing if the results were really any better, and for my purposes, (Very small scale, one off hobby use.), poly has been more then acceptable, and fast.


BrendaEM,

You can say that again!
Years ago I worked in a factory casting, grinding and recasting epoxy for fake marble counter tops. We wore full tyvec suits with hood and booties, goggles, long gloves, ear protection, respirators and face masks. If we were actually casting, a heavy “rain slicker” as well. We literally looked like we stepped off of a SciFi movie set! Still, it got in sometimes.

Bob, B.

[ckelloug]

ckelloug,

Imagine the pain in the @$$ that cutting and grinding hundreds or thousands of hard facing rods would be. And how relatively easy pouring bearings would be, thats mainly why I've been thinking that bearings would be better. THEN, it occurs to me, how about using roller bearings? It would still be a pain placing them though. Would you be able to just pour epoxy over the top of the rods, and still get acceptable penetration with the “sand”? Would it be necessary to use “sand” to integrate the E/S with the E/G? Some sort of jig? Shake them into a flexible tube so that you could hold the tube over the mold and have the bearings drop upright into the epoxy, as you moved the tube back and forth?

Hopefully someone with steal wool, polyester and epoxy resin will make a sample of both and compare them. I've been curious as to the difference, but I haven't been willing to spend the money on epoxy, not knowing if the results were really any better, and for my purposes, (Very small scale, one off hobby use.), poly has been more then acceptable, and fast.

Bob B,

I haven't thought a lot about bearing surfaces personally. I've spent my time poring over books, web sites, and datasheets up to this point rather than pouring epoxy. I'm almost done acquiring the additives and information necessary to start aiming for the strongest possible composite. Walter AFAIK is the first one to actually start building an E/G machine and I believe he is planning on using metallic bearing surfaces and threaded metallic inserts for bolts.

Most of the regulars here whose opinions I've seen consider E/G ungrindable and unmachinable. One of the interesting things about poured composites is the fact that you can pour an epoxy surface that has a flatness equal to a good surface plate as long as the surface you are pouring onto is level. Such a surface is certainly more accurate than a home shop enthusiast can do without a precision diamond surface grinder.

I have no idea really about your bolt embedding idea. My instinct is to guess that it wouldn't be as strong or long lasting as a good metal insert and that it also would be more difficult to align precisely. The steel wool would provide tensile reinforcement in the area around the bolt which is good but ultimately, resin is still present in the area and definitely not as wear resistant as metal.

Without doing the experiment, it would be almost impossible to predict from theory how well it would work or long lasting it would be. I haven't started experimenting yet so I don't know.

BrendaEM,

Thanks for the admonishment towards safety and the interesting note about the affinity of pets and resin. I never would have thought of that. Not inhaling the finer fillers is also good advice as there are a lot of warnings these days about silicosis. Most of the additives are not as "hazardous" as the epoxy.

The titanates I just received had to be shipped with hazmat warnings only because alcohol used as a solvent in the solution is flammable and by law can't be shipped without warning labels. (The isopropyl alcohol in it is the same isopropyl alcohol you can buy at the pharmacy for 59 cents and it most likely shipped in a truck with hazmat placards to get there.) Not drinking any of the additives or using them in the kitchen is definitely advisable.

Regards all,

Cameron

[walter]

_
_
Very first and unofficial picture of my mineral casting. Cameron's Formula, all natural color, no pigments, 150lbs with motor. It's straight out of the mold, still has some plastic and artifacts on it- I just vacuumed it for now.





The idea behind mineral casting is that the part should be service ready straight out of the mold. Many components such as steel slide ways, linear rails, ball screws, inserts, wire ducts, coolant troughs and ducts can be cast into the part during the casting process. All these components become an integral part of the finished casting. The Cold Process enables epoxy-granite to integrate both plastic and metal into one casting eliminating many steps, which significantly reduces the machine's assembly time.


My casting is somewhat unusual in that there is entire linear stage cast into the part. Normally you would have only inserts and guide ways in there. I simply didn't have time- it was easier for me that way. Next casting will be done the usual way- as a solid block.

Thank you all for enabling me to experience all this! :cheers:
_

[Glacern]

Walter,

Very impressive, to say the least. Is the quartz you used black in color?

And from what I understand, you used vibration and a de-airing agent, but no vacuum? I'm particularly impressed by the complete lack of surface voids.

Congrats and thanks for posting.

[gerryv]

Walter,

Frankly it is an incredible piece of work that exudes apparent quality. Although I'm retired for a time from some interesting roles in highly competitive industries, there is something that I fail to grasp here.

You commented "I simply didn't have time - it was easier for me that way. Next casting will be done the usual way- as a solid block."

What confuses me: In order for CANUSA (USCAN if you prefer) to regain it's ability to build machine tools, etc. "here" for our own very large markets and perhaps even for export, we need to get our costs down to a point where our product's actual value, rather than perceived (a killer word) value is even only a penny greater than the heavy, shoddy junk that's shipped to us from half the way around the world - using increasingly expensive fuel, to our advantage.

This thing is gorgeous. No doubt well engineered as well. The process seems innovative and, from following this forum from time to time, apparently focused on using lower cost materials. Also, "didn't have the time" suggests more efficient/lower cost. "Was easier" suggests the same plus less complexity, meaning opportunity for lower error rate and less waste. All beneficial things when I was involved.

I look at the terrible quality, lack of dependability and high service rates of most Eastern produced "junk" machines that I, like so many other private and less than major producers are forced to buy because there's no affordable middle ground anymore and I wonder.

When I compare them to this wonderful piece you've produced; apparently in a truncated (meaning good) process, I'm immediately thrilled by it's potential and, by comparison to what I'm forced to use, seeming readiness. Less so by your stated intent on going back to "business as usual."

I'm certainly not trying to be rude or presumptuous here so please don't take it that way. Perhaps I misunderstand the goal and objectives.

Impressed. - Gerry

[BrendaEM]

It would be interesting to use a surface plate--as a part of the mold, such as where linear rails attach. It would take dozen coats of wax to let it release, but it would be pretty flat.

My thinking, as such, is there are usually only one or two surfaces that need to be true on each part.

Walter, the part looks excellent.

[BTW, I would not use polyester resin because it absorbs moisture, and that can't help make it stable. You can bend parts laied up with polyester, with a heat gun.
Epoxy is supposed to be more stable overall.]