[greybeard]

2500 messages.... I've got bagsies

OK - the party's at your place.

[jhudler]

OK - the party's at your place.

Ok as long you bring the Scotch!

[greybeard]

...and Walter brings the rocks.

[lgalla]

Moglice/Granitan.
Found this:
Application of -moglice- low friction wayliners.

We like to confirm that we have been using -moglice- for approx. 2 years with success in our production. Using your low friction wayliners we find essential advantages against conventional methods:

Enormous cost savings by your moulding technique, Production of true to measurement slideways with:

-low coefficient of friction (also for smallest steps),
- no stick-slip,
- no wear.

These results have also been decisive using -moglice- to coat our novel Granitan polymer concrete.
Larry

[walter]

...and Walter brings the rocks.

You got it!!

Moglice/Granitan. We like to confirm that we have been using -moglice- for approx. 2 years with success in our production. Using your low friction wayliners we find essential advantages against conventional methods.

Thanks Larry, that is a significant piece of information. This could mean that E/G bases can be cast in 2 stages: the main base cast separately with precision surfaces grouted in or cast by replication technique (moglice). Extremely interesting!

[jhudler]

I've been wait'n to try that out! An EG lathe design using kinematic ways and no steel!

[jhudler]

http://www.schneeberger.com/medias/g...re_English.pdf

Nice EG Examples!, do a search for "mineral"

[greybeard]

er, remember my thoughts on post spin casting of re-surfacing my beams, looks like I'm in with a good chance. :wee:

Anyone looking for a lage chunk of flat granite in UK?
I've been trying to find the UK equivalent of Larry's worktop leveling resins(?) and finding a reference to Kencoat, I tried ebay. I don't know what it was designed for originally, but I'm sure someone might find 1.75 ton slab of granite useful. http://cgi.ebay.co.uk/ws/eBayISAPI.d...romZR40QQfviZ1

[lgalla]

Some new Zanite guidlines:
http://www.ppc-ltd.com/faqzanite.html
Interesting,the standard mix uses 1/2"rocks.
Also download the brochure in the top left corner.
Larry

[jhudler]

WHOA! "ZANITE composite has a density of .082 lb./cu. in. (2.27 g/m)

That's exactly what what our current formula produces .08175 lbs/cu in (2.262 g/cc)

[tmarks11]

anybody happen to mention yet that the New Syill mills have "a solid concrete polymer coordinate table in a steel protective cover"?

[walter]

That sounds more like Datron http://72.14.205.104/search?q=cache:...ient=firefox-a

http://www.youtube.com/watch?v=NP4sDX87JE8


EDIT: Wait, I found it. Syil X4, coordinate table- solid concrete polymer on a steel base. Interesting!
_

[jhudler]

Nice video! Stiffness indeed... The spindle runs with 40.000 rpm and 3kW power! LOL! Do the Modulus on that!

[fdew]

Just a quick hello right now. A friend told me about this thread. It looks like a good place for me to learn some more about Polymer Concrete. I have designed a few things out of it. I started back when Harding was the only source in the US. A couple of high precision optical test machines, and a machine base. It is great stuff. Easy to design around, wood molds, You can cast in any number of things from ground plates to plastic conduit. It loves epoxy so many things can be added after the casting for very high precision. It dosn't look like anyone on this forum needs encoragement, but let me try anyway. It is a great tool. Go for it.

Here are some toys I have made.
http://www.lbpinc.com/lbp-pg4.htm
The top machine has the base and the machine itself made from Polymer Concrete
The bottom picture, the units are 30 feet high and 30 ton each.

Frank

[ckelloug]

fdew,

Welcome to the Epoxy Granite Thread. Since you're new here, you might check the index thread which is a sticky in the thread menu in this section of cnczone. It will help you get oriented to our discussion without having to read 2500 posts of banter. We're busy here engineering open-literature epoxy granite formulas for the use of the community.

Your machines look good on you web site. Any advice on constructing machines is appreciated. I personally know much more about the science of the material than how to use it at this point.

Regards all,

Cameron

[jhudler]

Frank,
First welcome to the thread!
Nice to have an actual user of commercial EG.

Have you actually poured EG yourself or farmed it out?
Did you make the molds?
What was used on the inside of a wooden mold and what type of mold release was used?

Jack

[fdew]

Your machines look good on you web site. Any advice on constructing machines is appreciated. I personally know much more about the science of the material than how to use it at this point.

There are some great features to using Polymer Concrete. Some one asked if most machine builders use reinforcement in the PC I have not seen any one use it. I often had customers ask for it and I would try to try to them out of it. It changes the characteristics of the PC making it dampen less, PC is great stuff and usually doesn't need any help.

Some one asked about what happens is a fork lift bumps a machine. I wouldn't worry about it, Fork lifts are relatively easy to repair. (Grin) Seriously, I have never seen a broken PC structure.

I was taught how to design with the stuff by Brian Eaton. He started the PC division at Handing and received his training in Switzerland. I am trying to get him to join the list.

BTW I say Polymer Concrete, not Epoxy Granite because most Polymer Concrete is not made from Granite. I personally don't think the stone used makes a lot of difference. The vendors will tell you it does, but then you find that they are using stone from a near by quarry.

I use 3 in. wall minimum unless I am in a bind, then talk to the person who will poor it and get an opinion. The issue is flow of rock in the mold, including getting it in, and getting it to settle right and get air out. If you need thin sections you can cast in other materials such as steel, or even granite.

If the mold is not going to be disassembled to remove the part then you need draft. 3 deg is minimum and 6 deg is better.

Think about the mold as you design, and think about how the part will be poured and how the mold pieces will be held, and how they will be removed.

It is possible to install voids in a part to save weight. I have used plywood boxes held in place with threaded rod and cast in permanently.

Inserts can be any shape. Threaded inserts tend to look like a thread spool (big on both ends, and small in the middle. You want a real "bad" finish on the walls of the insert, so the epoxy can bond to it. inserts are simply bolted to the mold walls and the rock poured in around them. This allows you to have threaded holes any where you want them.

Plastic pipe or conduit can be run for electricity, water, air, or whatever. You just bring them out through the walls of the mold to hold them. I have even cast in electrical boxes by bolting there cover to the mold.

Have you actually poured EG yourself or farmed it out?
Did you make the molds?
What was used on the inside of a wooden mold and what type of mold release was used?

I have not poured them my self. I have been fortunate in that I have been able to design some BIG stuff. It would take more then one person to handle them, and the guys that do it for a living do it very well. This is not to say that it is complicated, it is not, It just requires moving a lot of heavy stuff around.

I have worked on the post processing. adding precision flats and mounting surfaces, gluing large pieces together, fitting precision parts into the casting, ETC.

Molds. I have seen a number of steel molds used, They allow for a good finish, and they last a long time. I have always used wood molds. If you need less then 25 pieces a good wood mold will do the job. These molds are made like a house wall with hard wood "studs" and plywood "walls" Every thing is glued and screwed, All imperfections are filled and the inside mold surface is well sanded. inside corners will be filled with hard wood or some times aluminum "trim" so they are rounded. The finished mold is a work of art. It looks like furniture.

If there are parts that will need to be pulled, such as the part that creates a pocket in the final part then particular attention is given to a very nice finish.

If there is a part that needs a nicer finish, or will see a lot of abuse in the pour then some times a thin sheet of steel is added to the inside surface. By making pockets in the mold, you can have parts stick out such as steel mounting surfaces, or pipes, I have made an entire side of a mold from steel plate when a customer wanted a steel magnetic surface on the finished part.

The bottom of the part tends to be the top of the mold and is often open. This will be a rough surface and is often epoxy rich.

The Epoxy serves two functions in PC First it holds the stone together. but before it does that it serves as a lubricant to allow the stones to move around and find there spot (compact) Therefor a bit more epoxy is used then is wanted in the final mix and the surplus rises to the top as you vibrate the stone.

A core sample from a good casting will look like one stone. You don't see individual rocks and you don't see any voids. The bond is that good. Back to molds for a bit. If you need a fancy shape pocket in your part, Aluminum is a very good material to use in the mold. The aluminum oxide that is on the surface of all aluminum makes a great mold release. The other side of this is that it is hard to bond aluminum to a PC part. If you have to do it, you need to make the aluminum part so it is trapped in the PC (ridges, holes, ETC.)

On the other hand, don't even think of making part of your mold from epoxy. all the mold release in the world wont let you get it out. PC loves Epoxy.

This love of epoxy is often a good thing. You can add all sorts of things to your part with epoxy. You can even create precision bores by waxing a shaft and then epoxying it in place in your casting. let the epoxy setup, and pull the shaft and you have a precision bore in a part you couldn't have got to in order to machine. I have heard of waxing the OD of a bearing and epoxying it in place and leaving it there. The wax is there in case the bearing ever needs to be removed.

BTW this method is not new. engine builders in the early 1900s formed Babbbitt bearings by pooring the material around the crank shaft. for a mold release they used smoke Well, actually carbon from the low flame of a kerosene lamp or candle.


How good a surface can you make? I have taken polished glass (optical polish 1/4 wave) and waxed it with a good paste wax and buffed it, then write on the glass with a sharpie. Lower this glass plate into a pool of .1 in thick epoxy (ITW silver 500) let it set up, remove the glass and you have a precision flat on your part. Except where you wrote on it, you can read the writing in the epoxy

You mention mold release. I don't know what was used. I know it was painted on the mold. Perhaps we can convince Brian Eaton to tell us.


BTW The machine you see on my web site was cast in two pieces. The base was a large low precision casting, and the head or actually machine was a smaller high precision casting and the two were glued together.

Frank

[jhudler]

Frank, that's a lot to digest.
Like the information about reproducing surface plate from Super Alloy Silver 500.
Silver 500 looks like a diluted epoxy (Novolac?) with Calcium Carbonate, Fumed silica, Magnesium silicate hydrate.
Should be easy enough replicate as it doesn't appear ITW sells the stuff anymore.

Would love to hear both Brian and your's critique on this thread and its results so far.

A lot of what's been learned has been from researching and just plain old trial and error!

The actual mechanics and chemistry is (once you get use to it) fairly straight forward.
What's missing or incomplete in all the research is the process.

Jack

[ckelloug]

Hi all,

I'd like to welcome our new members and say that lots of great information is being posted. . . While participation here is encouraged for anyone who has a question or answer, I would like to ward off problems concerning proprietary information.

Hopefully it is clear that posting the proprietary or trade secret information from any vendor is not appropriate here. Nobody has done that but it should be known that this thread is composed entirely of information from the open literature, trial and error, and first principles engineering. We would like it to stay that way.

Non-proprietary information and discussion are always welcome regardless of the source. This comment is not meant to keep anyone from posting here, it's just a reminder that the information we collect here is publicly available and must not be misappropriated from any of the companies which have invested sizable amounts of money in their materials and processes.

In short, the privilege of our own open E/G formula comes from respecting the formulas of the other participants in the game.

Cheers all,

Cameron

P.S. Since I just met him in real life, Best of luck to harryn.

[harryn]

Thanks for stopping by Cameron. It was interesting.