[ckelloug]

Hi TZE Paul,

No worries about your English. I cannot speak a word of Russian. I did manage to find a web page on Russian Epoxy standards however and ran it through google translate. http://www.gosthelp.ru/text/GOST1058...epoksidno.html


The epoxy is not the most important part, it is the aggregate mixture. EG should work okay with most epoxies but will obtain better performance with good ones.

Based on what I currently know, I'd think ED-20 would be fine. PEPA appears to be equivalent to DOW DEH 29 hardener. The dow data sheet suggests that this is a hardener that is very flexible which may not be so good for E/G. I would also think that the dibuthylftalate will make the mixture even more flexible leading to the lack of strength mentioned.

In general, it is a sign that the epoxy is well bonded if the stone rather than the epoxy broke. The epoxy should have a higher tensile strength than the stone.

I found this Russian supplier's product list: http://www.chimexltd.com/eng/content...647&idt=static


Based on this, I would suggest ED-20 epoxy and isophorone diamine which I have used in some epoxy measurements.

80 MPa tensile for E/G is optimistic, 25 MPa is probably more realistic. For compressive strength American manufacturer Accures castings obtains only about 125MPa compressive strength. Modulus can be expected around 30GPa for a good mixture.

Flatness is probably achieved most easily by a precision ground mold. We think it may be possible to cast an accurate surface with a very low viscosity epoxy like tabletop epoxy but nobody I know of has actually tried it here.

The larger the stone, the weaker the material but the easer it is to achieve good modulus numbers.

A mixture of silica something like Greybeard and AFAIK are discussing is what I would recommend although it is important to get the 3-4 mm size range in addition to the other AFAIK has already found. The precise percentages of each silica size in the mixture are dependent on which sizes you have available.

I hope this helps.

Regards All,

Cameron

[TZE]

2 ckelloug:
Thank You for reply! I notice some tricks of the trade from your post .
I can sit 'n' relax about type of epoxy resin for my first steps!
So I will try with ED-20 & PEPA (isophorone diamine is a rare thing out there - but I'll try to find it) and I try to mix components accurately. I'll try to achive compressive strength of E/G pice about 60-80MPa. I think that it is not so bad - I can reinforce casting with metal or glass fiber to achive about 60-80MPa for tensile strength ( it's main advantage of E/G, isn't it? )
But can I suggest than rather flexible ED-20 & PEPA is good matherial for damping of vibrations? Or it will play and vibrate like cell phone ?
Rather long&rigid steel sleeve with bearings and spindle in "shock damped" E/G headstock is an good thing for honing/precise boring/reaming I think...

[ckelloug]

TZE,

E/G is best for compressive strength. The properties of stone and epoxy are not so good in tension. Cast iron has a similar problem but it is a lot stronger. Flexible epoxy might help damping a bit but I have done no research or optimization on damping properties so I don't know how big the effect is. From a study showing that E/G did almost as well as pure epoxy for vibration damping, I suspect that flexible epoxy may not make a big difference.

PEPA was said in the article to make a somewhat brittle epoxy so I'm not so sure why the materials data I saw also suggested it was too flexible. You'll probably want to oven cure your parts in a mold to get the highest possible chemical conversion of the epoxy.

It is important to use as little epoxy as you can get away with.

Best of Luck,

Cameron

[mikegramkow]

Hi all, I'm new though I've read every post over a few week period, not much to contribute from me but I receive regular email and magazines from NASA Tech Briefs (I would recommend this subscription to every geek) and this was one of the sponsored listings:

One-Part Epoxy Adhesive Cures At 80 Degrees C

Save time, increase productivity, eliminate waste, and lower
energy costs with Master Bond one-part epoxy adhesive/sealant
Supreme 3HT-80. It requires no mixing prior to use and has a
shelf life of 6-8 weeks at room temperatures. Typical one-part
epoxies require 250-300 degrees F to cure, but Supreme 3HT-80 cures
in only 30 minutes at 175 degrees F -- even more quickly at elevated
temperatures, i.e., 10 minutes at 250 degrees F. It's 100% reactive
and contains no solvents or diluents.

http://link.abpi.net/l.php?20100525A1


Just thought it might be interesting, the website says that viscosity can be adjusted to individual requirements. It's from Master Bond Inc. I figured someone more involved than I, say our resident expert ckelloug for instance, might call for a sample and test it.

Mike

[ckelloug]

Hi mikegramcow,

I've requested literature from Masterbond on the supreme HT-80 with a description of the application. We'll see what we get back. Masterbond had a great reputation when I had to call them 10 years ago about EP3AO thermal epoxy and the rep teased me and suggested I apply for a job.

Regards all,

Cameron

P.S. I have the half-ton vibration table in my lab but I need to figure out how to get it off of the pallet, and then remove the vibrators, rewire them for 220V operation and reinstall them. It's somewhat difficult as each of the two vibrators weighs several hundred pounds and is held on with 3/4 inch bolts. It won't be easy. I'd take any advice offered.

[greybeard]

........ each of the two vibrators weighs several hundred pounds and is held on with 3/4 inch bolts. It won't be easy. I'd take any advice offered.

Engine hoist on legs ????
Regards
John

[ckelloug]

Hi John,

Glad to see you're still about.

The vibrators are under the table in a bid by the table's engineers to drive me nuts. I've been thinking floor jack under the vibrator and then undo the bolts but I still have to figure out how to get it off the pallet. There a picture a few pages back.

The engine crane would work to get it off the pallet but there's nowhere to go with the crane to get the vibrators. I suppose, I'll just have to put on shop clothes and plan to get very warm and go do it.

Cameron

[johnohara]

Cameron~

Looks like it's designed to be picked up with a forklift.

Couple of ideas:

Something with an articulating boom or chain-fall hoist. Stone yards, monument makers, mason contractors, etc. all have these kinds of trucks.

Once lifted, put some wheels under it to move it around -- bolted to the existing holes in the I-beams.

Or, put used railroad ties under the beams to give you room to work.

Looks pretty violent. Is the vibration speed adjustable?

~John

[AFAIK]

I sent two emails to touchstonefloors for the 3-4mm grading curve, I have received no replies. I've had a look on the internet for other sources to no avail, so I am going to see what I can find locally.

One thing I am trying to work out, does epoxy granite self-level to 0.005" or is it just the epoxy resin?

[the4thseal]

just epoxy, there systems meant just for that, if you do your part they do theirs.

[romandian]

which ones exactly? i have been thinking about injection types, that have a viscodity of water. any brand/product you have in mind?

[lgalla]

Epoxy at the viscosity of water would have plenty of reactive dilutents and would "blush"several days after cure.Blush is a waxy buildup on the surface.The proper type of epoxy for self leveling is rather thick and will not blush.As you are in Europe...Search google for table top epoxy.For US & Canada...http://www.uscomposites.com/kk121.html
Larry

[romandian]

the thick epoxies i tried so far do not level to 0.005 ". so i thought about using sikadur 52, which is solvent free and has the consistency of water.

http://www.sikacorp.com/tds-cpd-Sikadur52-us.pdf

[ckelloug]

Hi AFAIK,

Epoxy granite will not self level. Low viscosity epoxy with the right additives (tabletop epoxy) will self level but I don't know anybody who's actually tried here. The aggregate makes a mixture of thin epoxy and aggregate not self leveling. Certainly post about self leveling epoxy if you try it.

I'm off to the lab today to remove, rewire, and reinstall vibrators on the big vibrating table. Two come-along winches connected to the steel trusses in the lab roof combined with my trusty pallet jack allowed me to de palletize the table and remove the first of the two vibrators.

Regards all,
Cameron

[brunog]

Cameron,
You should take photos in all angles of your vibrating table and post them to give ideas to all of us DIYers.

Best regards

Bruno

[Steven.ji]

Hi all!
A am sorry about my bad English but a have a great interest about E/G.
I respect all users here, but some time i can use only Soviet (GOST) names for materials(with live URL and/or appropriate data), because i do not know how they are exactly named in Europe and USA.
I live in ...

Hi Friend

I'm intereted in Russia market very much. In terms of your message, I commincated with you as following

1. As you mentioned, Russia used to develope the E/G in middle of 80's. But as my information, my friend from Ryazan Machine Too works told me that nobody used to apply E/G in machine tool, till now nobody use it.

2. You killed air by torch, that mean you remove air by heat. In fact, manufaturers remove air by vibration. Heating is not a good method. Heating will damage molecular chain.
Small air bubbles inside E/G will be good for vibration damping.

3. Some of your fillers are cracked stone. As my opinion, this is not a good method. There's small crack in cracked stone. The performance of E/G will be reduced.


Regards

Steven

[Steven.ji]

ckelloug,

I have not found the aluminum oxide in the size I need yet. Could more quartz be used or some other material instead of the aluminum oxide? I have found another site that has quartz in size ranges of 1-2, 2-3, 3-4 and 5-8 (mm) http://shop.touchstonefloors.co.uk/p...roducts_id=160

Thanks to greybeard I now have the option to sieve the materials if I wish, but from a rough estimate of the castings, I would be sieving about 400kgs so would prefer not to do it.

Hi Friend

I used to engage in ceramic insulators. There's no any crack in the ceramic. With compact structure, the ceramic is very hard. The composition of ceramic insulaors contains aluminum oxide.

If possible, you may try the insulator ceramic particles.

Regards

Steven

[Steven.ji]

..........
............................................
One thing I am trying to work out, does epoxy granite self-level to 0.005" or is it just the epoxy resin?

Impossible!!

In terms of pure resin, the material can be self-level, but I do not know the exact data.
But for epoxy granite, this is definately not due to the reasons

1. the air bubble will go out from epoxy granite constantly during hardening. After complete hardening, you will some air bubble on the surface.

2. E/G will shrinage after hardening, so some of stone will stick out the surface.

So, the surface will not be even.


Regards

Steven

[veteq]

Hey Cameron,

Got a couple off questions for you:

I see a lot off writing on forums about 70Hz spec for vibrating EG,
most motors only go to 50HZ (3000RPM)

Would a 50Hz also work ?

If so, would a motor like this work ? (Look at the attachment...)

Also this motor spec says 400 and 230 Volt, so would this motor run on 400 (3phase) or also on 230 (1phase)

Do they need a VFD, or just plug it into the wall socket??

Sorry for my noob post, maybe you cann explain a bit...

Kind regards,

Roy

[ckelloug]

Hi veteq Roy,

I'm not that up on the vibration frequencies right now but I reread German Castillo's Ph.D. thesis and he says 30Hz to 70Hz and that the exact frequency was only of secondary importance.

The vibrator you have attached is a 3 phase model which will not run from wall current. The 440V/230V means that it is still three phase at either of those voltages depending on whether it is wired delta or wye. You either need industrial 3 phase power or a VFD to run it.

My concern is that the attached vibrator may be a bit small. Most of the papers I have seen suggest an acceleration between 2g and 4g is required for good compaction and those vibrators look a bit small for non-trivially sized parts. If you can bolt two of these directly to your mold and isolate it, they may have enough power to vibrate a small mold for a small part. If you have to power a vibrating table, I think they are small.

My own surplus 1.5m x 1m vibrating table weighs 500kg. Each of the two vibrators weighs about 50kg and delivers 16kN of force with the eccentric weights adjusted for maximum force. (Two vibrators are used to get vertical only vibration.) My table can vibrate any part I'll be able to make even up to a few hundred kg. I sat on it for 10 seconds as a test and it was ready to rattle my teeth loose.

Pictures of my table will follow when I get a chance.

Regards all,
Cameron