[jberg]

I have ask epoxy what include pre mixed carbon nanotubes so I don't mix those bye my self. This supplier have also some kind of paste what can be added to other supplier epoxy.

I have no any expierence of them product but here more info http://www.amroy.fi/TDS.php

I'm not sure that do they sell this stuff to private persons. I have a "one man company" and I live here in Finland so I can ask samples using my company name.

where do you get carbon nano tubes?

[Eng-Meethaq]

Hi, please I need an books and journal about concrete polymer . please help me since I dont fined it in net recently.

[garfieldsimons]

Episs
Companys fabricating machine bases of epoxy granite are not in the business of selling the raw material.I did a lot of research on the subject and there is little to be found.Sand is basicly granite and probably a good filler.
Idon't remember exactly the figures,but epoxy granite has 10 times the damping factor of cast iron and 50 times the damping factor of steel.
THE COST??? 1gal. epoxy $80 Maybee 10 sq ft/gal/1/4 thick.Figure it out,its
gunna cost mega bucks even with sand fill at 50%.
This is just off the top of my head.If anyone wants more accurate figures I will look them up again.
Any how I figured out a slab of real granite is 1/2 the price of epoxy granite,maybe less.A 4X8'X4"epoxy granite table top could cost 5or6 grand or more.A black granite surface plate 4X8'X8"with stand is $2600 from an E-Bay store.If anyone is still interested I will try to answer any questions or re-research my findings.
Larry

If you follow the auctions you will find used surface plates quite cheap. (I got a 3 x 5 for $50. Moving it was real fun though) Epoxy based is crazy expensive. Better to play with concrete.

[Nami]

You surely have a lot of experience with vabrating tables.

That cotroller you use is not a inverter right?

No, it's just a chopper circuit of some sort. Single-phase A/C in, single-phase A/C out. Way overpriced ($150), as you could build one for much less.

Do you know if when you use 2 motors lets say you have 2 motors that each one have 100kg force, will the table end up having 200kg of total power? Or its not cumulative?

It could be anywhere from less than 100 kg. if they were fighting each other, to 200 Kg. if they were in perfect sync. Think of 2 people pushing a kid on a swing from opposite sides. If you time the push right, the work is harmonic and each person should have to push 1/2 as hard for the same effect. If one person pushes too soon, you drain energy out of the "system" before pushing back.

I pretend to build my table using 1 motor first and do some tests, if I dont get a satisfactory result I will add the 2nd one


If you let a mixture on the vibrating table the time to get a complete compaction will be it real fast until you get the point that you reach maximum compaction? It doesn't change anything lets say letting it there for more then 5 min right? Looks like when you get the ideal rpm the mixture simply collapse to its compacted place...

It usually happens fairly quickly. In thicker pours, it's advisable to do it in separate "lifts", or layers, so that air bubbles don't have as far to travel before being released. Many variables will affect the vibration time, including viscosity of mix, vibration power. amplitude, frequency, method of attachment of mold to table, constant or fluctuating frequency, mold material, etc.

Thank you for the answers

No problem

[phil c]

Did anyone managed to build anything out of polymer concrete? I would be interested in your experiences and materials suitable for machine frames, tables, etc.

Here's a nice looking polymer/epoxy(?) machine table called X2 Mini Mill base

http://www.cnczone.com/modules.php?n...threadid=24879

Do machine manufacturers use reinforcements in their frames?

It's an interesting execution, but why pair a high strength/stiffness backbone with plastic and aluminum slides? One of the benefits of cast iron in the RF-45 knockoffs is that it makes a cheap, long wearing, very stiff bearing surface(once you get the fits right, which can be hard to do). The only downside is that it is heavy(dense).

Plastic and aluminum slides would have to be huge(compared to the 30 mm or so wide cast iron bearings) to be equally stiff.

A better, but more expensive solution would be fairly large diameter crossed roller slides- very stiff, very free movement, very expensive.

[ckelloug]

Hi jberg,

I'm still happy to test samples if you post the composition to the thread. I'd been taking a bit of a break lately as my checkbook and I both needed a rest in this endeavor.

I'm working on acquiring a surplus vibrating table and once I get it, I'll be back in business. There is only so far you can go on models alone and I covered as much of this ground as I could a while back.

Regards all,

Cameron

[DarkDesigns]

Hey all, just wanted to comment on the posting about polymer concrete/epoxy granite machine bases.

I personally have been playing around with various mixtures and aggregates.

I've spent many (exhausting) hours researching threads and forums about the concept.

I have found just as many variations to the "mix" as I have found people trying it.

The common factors are as follows:

Epoxy/Aggregate machine bases provide a MUCH greater vibration dampening factor as do cast iron or steel.

The most common aggregate of choice is crushed granite in various sizes ranging from sand size up to 1/2" or larger.

ALL "recipes" have reported great results in various forms, I have yet to find too many "horror stories" except from the "less informed" that have tried without doing the proper research.

Having siad that, my own experiences resulted in GREAT results. I have cast numerous structures including a rotary table base, a bed for a small gantry mill, machine bases for small equipment. MOst of my experimenting has been on the smaller nature (those of you with limited "play" funds understand) usuall never more than a gallon or so of epoxy resin.

The basic agrregate mix is what is used for the "structure" to become the "load" or "weight" bearing component of the mix, the resin being mearly a binder.

Various compositions I have tried, structurally, all were sound. Every thing from "play sand" (wash and dry THOROUGHLY first) with Aquarium grade pebbles....to... full blown Granite aggregate of various sizes.

All in All it depends on the "look" you wish to achieve as well as the structural "soundness"

Jagged aggregate holds better in the bond, but is harder to mix. "Rounded" aggregate mixes better.

I've tried Quartz also with FANTABULOUS results. (As quartz has better vibration dampening than granite.)

Best advice is start small, minimal cost. until you find a mix thats right for you and your application.

Regardless of what type of aggregate you use, shoot for a 14-20% amount of resin with hardener, should make a mix thats wet enough to "wet" properly, yet dry enough to hold some shape.

I ALWAYS gelcoat my molds before pouring in the E/G (or E/A?)
Much better surface finish. As most of my bases stay unpainted.

Hope this helps anyone thats interested in trying it. Gantry mill with the E/G base runs production plastics and wood at least 8 hrs a day, 3-4 days a week, and has been doing so for the last 2 years. Still as solid and vibration free as the day it was first used.

Regards to all.

[the4thseal]

pics?

[veteq]

CAD images will do also..!!!

Is the 14 to 20 % resin and hardener by weight, volume or Joule ?

[the4thseal]

Joule?
a unit of energy for the amount of epoxy? please explain.

[veteq]

long story, sorry............(nuts)

[the4thseal]

so you are not using Joules for measuring .....thank god.....dd not want come grips with that idea.

[ckelloug]

I saw this video on youtube looking for something else today. It's too funny not to post here. . . [ame="http://www.youtube.com/watch?v=2GR2lOSAblY"]YouTube- Epoxy[/ame]

Veteq, was your comment about joules related to mix ratios by the amount of exotherm or specific heat of the mix or are you just messing with us

[veteq]

Veteq, was your comment about joules related to mix ratios by the amount of exotherm or specific heat of the mix or are you just messing with us

It was the exotherm in relation with energy that was needed to produce the basalt stones. ( exotherm Joule / stone ) :stickpoke

after i finish my radiocarbon dating proces for the basalt stone, i cann start the real calculation............

Mwuuauaaa....!!!!!!!!!!

[daedalus]

Happy new year everyone. Just wanted to share a link to a paper i found discussing a candidate material design that has compressive strength comparable with industrial epoxy granites. I havent gone through the whole thing, but it is interesting in that it lists the compressive strengths of several commercial materials and epoxy content percentages.

Their approach does make me think, if the goal is to replicate zanite or harcrete, would it be possible to reverse engineer their mix ratios by cutting up a sample, polishing it, and measuring the particle areas / ratios?

[veteq]

Hey Daedalus,

Had just a quick read, but it looks like Zanite uses 8 - 9 % epoxy by weight.
Thats a lot and different then all the studies overhere.

If so, it will make the proces a lot easier.

Happy Year to everybody.

Roy

[daedalus]

Hi Roy,

I have been trying to track down the papers referenced in that one. There is a paper in portugese that does a bit more work on calculating the estimated coefficient of elasticity, and presents measurements on around 10 mixes, down to 13% epoxy ratio, its available here: http://vsites.unb.br/ft/enm/metro/papers/cobef1_03.pdf, you can get a reasonable quality translation through google.

Tom

[veteq]

Hee Tom,

Nice paper, aren`t the 10 comparisons about maximum tension (sigma)
What i understand is that the E- modules is only determind for 23 and 20 % epoxy by weight.

Am i wrong? maybe a potugese guy cann look at it?

Kind regards,

Roy

[veteq]

Had just a quick read, but it looks like Zanite uses 8 - 9 % epoxy by weight.
Thats a lot and different then all the studies overhere.

If so, it will make the proces a lot easier.

Roy

If i remember the Germans i posted about a few times (Thomas zietz)
Where using the vibration table to get the cores right when using small amounts of epoxy by weight ( < 6% )

If Zanite uses around 8 - 9 % the mixture will be very wet in relation to getting it in the mold. There where a lot discusion about the E-modules will be very bad in this case, but i did a few test with EEM and they showed me that for almost all designs i made, the stiffnes would be more then enough and diplacement would be minimal.

Think the ease off use will be far greater then the negative side of the cost of a bit extra epoxy.

Roy

[daedalus]

Hi Roy,

If you look at the text in "3.2.2 – M&#243;dulo de Elasticidade", there are estimates for 13&#37; and 20% epoxy content if my attempt at guess the words is correct.

Tom