[jhudler]

Walter, Thanks, I see the need to create a process where a shell can be made that is then filled with EG. That shell can be the "sporty" exterior where you can personalize it or used to add real structural support in the form of woven fiber mats.

But all things a side; the need to create molds and the methods used needs to be ironed out and well documented.

I find that UHMW material is an excellent mold material for EG. I've used small holes in the mold to allow air to escape and to blow air back in to demold.

[greybeard]

I've just done a quick calculation on the amount of epoxy required, as per Gamski/Gupta ( 31 micron thick layer on average) for two different particle sizes.
I took 100 ccs of 200 micron particles in the first case, and 2mm particles in the second.
This gives a volume of each particle as 0.004189 cu mm for the first, and 4.189 cu mm for the second.
Assuming both to have a packing value of 72%, the total number of particles is 1.72 x 10^7, and 1.72 x 10^4 respectively.

However the surface areas are 2.16 x 10^4 sq cms and 2.16 x 10^3 sq cms, so the volume required to fulfill G/G's requirements will be 67 ccs and 6.7 ccs epoxy for 100 ccs of 200 micron and 2mm particles respectively.

I think that as an approximation this bears out Jack's observation of the amount required to wet G200 at 40% by volume, which at first sight seems a lot.

Jack, is your "UHMW" material referring to ultra high molecular weight polythene ?

John

[jhudler]

Jack, is your "UHMW" material referring to ultra high molecular weight polythene ?

John

Yes

[jhudler]

Just mixed my first batch of thick epoxy 3:1 US Composites.

It seem to take a bit more to wet out and requires a bit more force to mix but other than that I do not see any reason this cannot be used. I did use 525 and 969 agents.

I also don't think the BYK-A 525 is doing much for us when mixed with aggregate. Mixed alone with neat epoxy the effect is very dramatic, but other than that...

Jack

[Steven.ji]

For the ploymer concrete, it's called as "expoy granite", "expoy marble", as my opinion that's not exact name. With respect to ploymer concrete, the filler is not only granite and marble, but also other minerals. So the exact name is "plymer concret","mineral casting" etc.
Genman studied the subjet since the second world war, till now polymer concretr is a poven technique. Polymer concretr has been widely applied in machine tool for metal work, wooden work etc due to the performance and price advantage.
Concerning the polymer concrete, the integration is the first advantage. it can be cast in pipes, wires, hydraulic tube etc. Precision is the second advantage. If somebody want more detail advantage, I will provide.
For the proportion of sand and expoy, sand is more than 93%, and expoy is less than 7%. So the price is much cheaper than cast iron.

[walter]

Epoxy-granite is more of a symbolic name. While original formulations of polymer composites came from concrete filling of machine tool bases and included concrete, more recent formulations consist mainly of quartz or granite materials in an epoxy composite. Also note that Fritz Studer AG of Switzerland, who invented the technology in the early 1970s, did it with epoxy and granite http://findarticles.com/p/articles/m...v93/ai_3647171

I like the term "mineral casting". Note that polymer concrete is used for pipes, airport runways and trash cans, which only confuses everyone.

* * *

BTW, here's the table that I made last week. Pretty good for a prototype, although I'm seeing lots of small voids. I placed a layer of aluminum oxide then poured E/G without vibrating it.
_

[jhudler]

I am not sure what you are trying to explain; that our use of the phrase "epoxy granite" is incorrect?
Granite is primarily composed of quartz and feldspar, the two most common mineral composites on the planet.
Generally Granite is 72% Quartz, 15% Aluminum oxides, and others which if you look at our current formulation, is a close approximation (though accidental) of Granite.

I just had a email from a well known supplier of epoxy where I used the phrase "polymer concrete", they told me that they did not work with concrete. I wrote back using the phrase "epoxy granite" and they understood; I wanted to "Glue a box of rocks together".

Call it "polymer concrete", "mineral casting", "thermoset composite", "particulate composite", or what ever you like.

Here we refer to it as "Epoxy Granite" because simply; it saves time.

We here "Glue a box of rocks together"... who coined this phrase? Walter?

[ckelloug]

Stephen.ji,

We're interested everything people have discovered about mineral composite machine parts whatever name you want to call them by.

This thread settled on the name "Epoxy Granite" because polymer concrete usually implies a polyester resin based formulation according to Ken Lipovsky, the applications engineer for polyester resins at Reichhold. The nomenclature has also changed since the 1970's when some of the technology for epoxy based particle composites was originally researched.

If you have any information on the proportions of rocks and sand to epoxy used in other formulations, I'm interested. I've done a lot of research and believe we are near the optimal formula. My calculations, based on the work of French Researcher Francois de Larrard, indicate that between about 7 and 12% epoxy by volume should work although practical considerations make the lower epoxy mixtures a touch tricky. Lower epoxy mixtures also require carefully graded aggregate.

Thanks for your post and if you have more to say about what you have learned, please feel free to post it as we are always interested.

Regards all,

Cameron

P.S. The lack of posting here doesn't signify a lack of activity on the subject lately. I know that both Jack and Walter have been busy working on this as have I and most likely others.

All of my work lately has been involved in getting my shop and lab area set up to do effective research on E/G which doesn't make for good posts here. My machine shop now has power and the lab will have a 48x36x36 oven for post curing parts later this week. I've got my Bridgeport mill up and running although there are issues but my big accomplishment of the day was crashing my lathe and breaking the two iron castings that hold the half-nuts (chair)

I've already communicated with harryn about meeting this week, but I'll be on travel in the san francisco bay area from the 11th to the 18th if anybody else who follows this thread and lives in the bay area wants to get together. Just send a PM if you're interested.

[jhudler]

I'd make some nasty joke about turning on a lathe with the half-nut engaged only...
I wrecked the blade insert in my table saw today by trying to tilt the blade while it was running. Not a problem when you have an insert that's designed for a tilting blade.
Good thing my head was below the table when the insert took off at 400 MPH!
Now I have to realign the trunnion. Just one of those says when you just, walk away.

[lgalla]

Lucky Jack!
I suppose your insert was just a piece of wood.Kickbacks are no fun.One of my employees got a kickback from a piece of 18mm birch,2'X3'inthe(nuts).He was off work for a week and naturally I paid his wages.I would swear his voice is higher.Amazing what a 10Hp/14" saw can do.This is why I want a large E/G router.I hope it is safer than pushing sheets through a saw.
Jack I think Walter coined the"Glue a box of rocks together"I coined the E/G,E/Q,ESP terminology.Perhaps the final aggregate mix should be termed:
E/G/E/Q/AL02/ZeO2.Naw! E/G should be fine for a bunch of rocks glued together.
Larry

[jhudler]

No just your average melamine faced, high density phenolic laminate insert.
http://www.woodcraft.com/family.aspx...e=details#tabs
Sheared the hold down tabs clean off!

[jhudler]

Walter,
How did you hold all those inserts in position while you pour the EG?

Jack

[jhudler]

2500 messages.... I've got bagsies

[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!

[walter]

I glued them in place with epoxy. It sealed the hole perfectly.

[greybeard]

...and Walter brings the rocks.

[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!

[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

[jhudler]

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