[walter]

Max,

It appears that the bearing surfaces are ground after casting, correct?

I believe I've got the sample of that very material. http://www.cnczone.com/forums/showpo...postcount=1369
It polishes to a very smooth finish and is both strong and durable.

[greybeard]

Max,

It appears that the bearing surfaces are ground after casting, correct?

I believe I've got the sample of that very material. http://www.cnczone.com/forums/showpo...postcount=1369
It polishes to a very smooth finish and is both strong and durable.

The "diorite" component in their formulation rang a bell. The solid stone takes a high polish and was used for statues, so I'm not suprised that theirs takes a polish.
I wonder what their ratios are ? I don't recognise the way they have expressed the particle/sieve sizes, if that's what they are.
Perhaps you could identify them for us Max, and thanks for the link, by the way.
John

[jhudler]

Wow those are huge chunks of aggregate!

[MaX-MoD]

they are using 0 to 4mm diorite and 4->6; 6->10; 10->14mm blue granite from a region of France cause it's less expensive.
no data on proportions, thought.

and yes the bearing are ground after casting. I beleive it's diamont disc they are using.
I find the grinding of the EG amazing! never tought it could give such a nice result!

also they drill into the cast to glue inserts for mounting the linear guides. avoids grinding the inserts I assume^^
casted-in inserts are only used to assemble the parts of the machine.

the sample y received looks very similar, and comes from France, it should be this.

[walter]

Jack, they appear to be using calibrated granite http://www.cnczone.com/forums/attach...2&d=1186437687

This, I believe, is the process http://www.cnczone.com/forums/attach...2&d=1186331184

Great PDF Max, thanks for posting!

[And if anyone reads German perhaps they could translate this ↓ ]

[MaX-MoD]

well thank you all the great contributors of the threat to make me discover such an interresting material

it's a user from French forum usinages.com that gave me the link.
and say I gave a look at microplan site to find an affordable granite plate and didn't seen the link at that time

[MaX-MoD]

Germans seem to be far more aware of EG.
have a look to all the links you get on google when you search "mineralguss"!

http://www.epucret.de/ (english)
http://www.neumann-mineralguss.de/nmtie.htm
schneeberger
etc. etc.

hope I will have this 'stage' (is it the word in english? kinda job you do to complete your studies) opportunity at scheenberger

[ckelloug]

MaxMod,

Thanks for the link. I just posted in my terrible french over on the usinages site with the info on Francois de Larrard, the French Scientist whose book gave us the formula for the aggregate sizes.

In terms of density, the larger the biggest aggregate, the easier it is to get a high solids fill in the mixture. For us home shop folks, I think small aggregates are easier to deal with and if selected properly, they are generally stronger than large aggregates according to the theory.

Jack,

The DGEBF resins are stonger but often require heat to cure and are more expensive from what I've read. Not all of us will have the giant lab oven I just scored on e-bay for curing parts. The DGEBF resins would definitely be good for critical parts but for things like machine bases that you want to be heavy anyway, the DGEBA resins seem fine.

While the Reichhold 37-127 and 37-606 combination is not that strong, don't forget that the samples that have been tested up to now have failed in the aggregate. These resins also are pretty good on strength as low viscosity DGEBA resins go. I looked at an awful lot of others and some are 1000psi weaker than ours.

There are probably going to be several formulations according to purpose and available tools that we'll come up with in the course of our research. I personally am going to stick to the Reichhold stuff for them moment until I have time to investigate the variables pertaining to additives and the effects of different processing on strength. I assume that most of the other variables won't change when using a stronger drastically more expensive epoxy.

One other note: Most of the high strength DGEBF resins I saw had hardeners that were classed as hazardous materials. Corrosive was the most common. I'd say that some of these materials are probably not the greatest thing to handle outside of a lab environment. I certainly don't want to ship them to anybody or do all the paperwork involved to ship hazmat stuff.

Regards all,

Cameron

[lgalla]

Cameron,I agree with all your last post.I might add if the aggregate is fracturing first,higher epoxy ratios with lower viscosity may be easier to process resulting in less entrapped air and a stronger product.
Post cure is cool,er hot!In large RTM molds copper or alu pipes are embedded in thick castings and cold water circulated to remove excessive exotherm.After cure hot water is circulated for the post cure.Large parts can be post cured without the need for a large oven.
Larry

[greybeard]

.........Post cure is cool,er hot!In large RTM molds copper or alu pipes are embedded in thick castings and cold water circulated to remove excessive exotherm.After cure hot water is circulated for the post cure........
Larry

Then you could circulate water to keep your machine bed at a constant working temperature. Neat.

John

[Viperia]

This is a damn long thread and i have read as much of it as i could but i cant understand if there have been any machines built this way or if there only have been done some test parts to see how it works.

Im in the stage of planing a metal lathe and if i could save some time and machining just doing on big mold of the main structure it would be great. No need to do lots of welding and other things that way.

So if i want to make a stable decent machine that can do steel, iron, bronze, copper, alu and plastics would this Epoxy-Granite be of any use to me? I have seen big machines from Mazak and other brands built with something i guess is E/P but how is the quality on the things i can make at home?

And is there some optimal recipie on how to mix the stuff to get the best result for this kind of usage? Hope someone can help me with this because i must say that it would probably save some time and money.

Regards,
Viperia

[ckelloug]

Viperia

Epoxy Granite is used for metalworking machines commercially by Mazak, Hardinge, Epucret, etc. The group of us on this thread is working on making a practical formula that is easy to use for home CNC machines. Walter on this thread has built part of a machine using some of the work here.

I and others haven't built machines as we are concerned with first precisely understanding the parameters of the material and the best way to use it. The flexural strengths and moduli are not known right now and as a result we cannot say with any certainty the thickness of the sections required to hold a given deflection in a part.

Walter's formula is posted here
http://www.cnczone.com/forums/showpo...postcount=1753

The formula that I currently recommend is:

1 part #6 Agsco Brown Aluminum Oxide
1 part #4 Agsco Quartz
1 part #2 Agsco Quartz
1 part #2/0 Agsco Quartz
1 part 3M G800 Zeeospheres
1 parts 3M G200 Zeeospheres

(Agsco is a U.S. distributor of aggregate.) 3M is the 3M company.

According to a computer model, we believe that this formula is only about 12% empty space which is then left for the epoxy. Exactly how much epoxy is the right amount is unknown at this point.

Regards all,

Cameron

[ckelloug]

Hey sposl, we haven't heard from you lately.

Likewise, dfro how did things go for you?

[Viperia]

Viperia

Epoxy Granite is used for metalworking machines commercially by Mazak, Hardinge, Epucret, etc. The group of us on this thread is working on making a practical formula that is easy to use for home CNC machines. Walter on this thread has built part of a machine using some of the work here.

I and others haven't built machines as we are concerned with first precisely understanding the parameters of the material and the best way to use it. The flexural strengths and moduli are not known right now and as a result we cannot say with any certainty the thickness of the sections required to hold a given deflection in a part.

Walter's formula is posted here
http://www.cnczone.com/forums/showpo...postcount=1753

The formula that I currently recommend is:

1 part #6 Agsco Brown Aluminum Oxide
1 part #4 Agsco Quartz
1 part #2 Agsco Quartz
1 part #2/0 Agsco Quartz
1 part 3M G800 Zeeospheres
1 parts 3M G200 Zeeospheres

(Agsco is a U.S. distributor of aggregate.) 3M is the 3M company.

According to a computer model, we believe that this formula is only about 12% empty space which is then left for the epoxy. Exactly how much epoxy is the right amount is unknown at this point.

Regards all,

Cameron

Hello,

Thanks for this great answer that now have shed a little light on my ideas and thoughts. Since i have to finnish another project i have in school i dont plan to start building any machine in a couple of months.

Maybe then some of you guys have done some great achivements and got a good recipie for this mixture that will fit my needs. So ill hang around and see how the work goes.

Thanks again for the quick reply!

Regards,
Viperia

[romihs]

Cameron,

I am still around.
I agree, I've dropped out completely. I have not done any further work on the EQ, but I am constantly following the thread, working on a EQ CNC lathe design and thinking of ways to make the EQ the best way that I can (de-gassing, vibration mixing, etc...).

Our daughter was born 7 weeks ago, so there has been little time for anything else. :-)

I'm here....

Cheers

Sandi

[walter]

Sandi, Congratulations on your new addition to your family!
:-)

[Mcgyver]

This is a damn long thread and i have read as much of it as i could ...........

and machining just doing on big mold of the main structure it would be great. No need to do lots of welding and other things that way.

then you didn't to the part about the modulus of elasticity. EG adds mass with excellent vibration dampening properties, but its not very stiff. it would not remove the need for a steel or iron frame/exoskeleton of steel imo unless it was for a machine with neglible cutting forces. i wouldn't predict great performance of a lathe made of either a steel fabrication or EG, but one of both has great potential imo (so long as the fabrication is stress relieved).

the downside is it is a really long thread and needs a 'knowledge management' solution, the upside is don't think there anything else quite like it as far as EC goes, a lot of really good content here.

[jhudler]

Stiff?

See walters posts 2101, 2103, and 2106.

The only support (walter correct me if I got this wrong) is the linear bearing on top and it is in tension.

If you were to create an EG Lathe, it would not have the same base design as one built with cast iron.
Same goes for steel, you design the machine based on the characteristics of the materials.

I have no qualms about casting a vertical column for a mill or a base for a horizontal lathe. The way beds and anything attached post casting would be factored into the design.

When you see this stuff in actual commercial use and casting my own pieces (small they may be) I believe you would gain a whole new perspective on EG.

This stuff is NOT just for damping. Otherwise I'd be building a furnace to cast iron.

Jack

[walter]

Larry Help!

I need some info on table top epoxy exotherm (and fast lol). Can this thing actually catch fire?
I'm working on 28" surface plate and got it smoking good (quarter inch layer but I heated the surface before pouring..)

??

[jhudler]

Curious... are you casting on float glass or surface plate?

I wouldn't breath the smoke.

Going to have to throw out that cast and start over. Wait 24 hours and then add the some heat. Slowly because you don't want to deform the plate.

Jack