[brunog]

Bob,
I personally don't want to go that way, I want to make a machine without welding, portland cement and rebar.

You want to make a machine based on Bamberg's paper, fine, DO IT!
Send us a post once it's done and please try to upload smaller versions of your photos or drawings, we all know how to enlarge photos WHEN necessary.

You can also refer to previous posts, I believe that is the reason why the post are numbered.

You don't like the way this thread is evolving, that's your right

I personally believe this thread has well evolved and that we are going in the right direction.

As Larry has said in a previous post; this will take time and be patient!!

That was my 2 cents

Bruno

[BobWarfield]

Bob,
I personally don't want to go that way, I want to make a machine without welding, portland cement and rebar.

You want to make a machine based on Bamberg's paper, fine, DO IT!
Send us a post once it's done and please try to upload smaller versions of your photos or drawings, we all know how to enlarge photos WHEN necessary.

You can also refer to previous posts, I believe that is the reason why the post are numbered.

You don't like the way this thread is evolving, that's your right

I personally believe this thread has well evolved and that we are going in the right direction.

As Larry has said in a previous post; this will take time and be patient!!

That was my 2 cents

Bruno

Bruno, I'll trouble you no more with too large photos or otherwise. Best of luck to you.

BW

[walter]

I love when Bob gets steamed about something, always a good read

You should visit his website- so much cool info in there. I always learn something new.

But he's got it all wrong when it comes to E/G.

Everybody knows that E/G works. It does. Period.

Not only that... It works better than anything else. If there is anything that can even come close, it would be cast iron.

Did I say commercial E/G? Because that's what I meant. That's what works.

The hobby E/G, on the other hand, does not.

So there you have it.

There's no need to build anything to learn that. I already know that.

The mechanics of a 15 ton commercial base are different, building a 15 ton base is easy- building a 0.15 ton gantry is not.

Density is the key- they have the density and you don't.

They put 15 tons of wet quartz in the mold, send the high freq shockwave and the thing gets rock solid. Beyond belief.

Gravity.

You won't get that with your 50lbs of sand. Gravity does not work on small quantities.

Here, try this.

Grab a salt shaker, wet the salt with some glue, and start shaking.
I'm not kidding. Start shaking and see if you can vibrocompact it into a machine gantry material.

That's the thing. Your 50lbs mold is the salt shaker. You can agitate it but it will never compact (enough to become a gantry material). That' it.

* * *

Now that the engineers joined in, we may be able to overcome these problems. Push the limits and make it work. But not without some tricky engineering.

Press Compaction is the only way to get the density at this point.
You can double the density just by pressing it.

But press compaction doesn't work on liquids, does it?

So you'll need to get rid of liquids.

But how you're going to hold it together without epoxy??

Well, that's where the tricky engineering comes in...

You lower the epoxy content to absolute minimum, then you lower it some more, add coupling agents, engineer the best mix possible, and then squeeze it to 1/3 of the original size.

That's when you realize the full strength o quartz.

The big firms are keeping this info to themselves so the only way to find the formula is through testing
_

[davo727]

Hi, Ckelloug - Very good post. I will keep watching this, One of the big issues I think is if a strong usable part can be made at the low epoxy percentages. Id have to look back at my posts to get the numbers but seems to me one of my batches that had a low amount of epoxy was not going to be very good for making anything. And it still probably had 30% more epoxy than what you guys are shooting for. So for making a big machine hopefully a good technique can be developed to save material costs. Also please take no offense to any comedy attempts, its all in good fun Dave

[davo727]

A question: Do you all think its mostly just a cost issue as far as epoxy percentages? Or is there a huge performance gain at the lower percentage also? Im thinking I could make a machine with steel and EG contruction and be ok with the extra % of epoxy in it. I cant make giant cast iron castings but it looks like EG can allow me to make a big machine. Dave

[ckelloug]

Walter et. al. Do not get discouraged. From my perspective, we're still defining what we need to make. Your experiments and those of others like WilliamD are what keeps theoreticans like me from reinforcing the thing with unobtanium plated moebius strips. How do you measure the surface are of that? Once we are really sure we know what we need to make then the engineering effort can go into how to make it instead of what it is.

Davo727,

In answer to your question about the epoxy fraction mattering, the amount of epoxy has a huge role to play. See my earlier post on this. http://www.cnczone.com/forums/showpo...postcount=1082

The bad news is that the lower the epoxy fraction the harder it is to make
Furthermore, from reading the references posted by the folks on the thread, the optimal level of epoxy depending on which source you believe is between 8% and 16%.


DAK3333: Totally awesome post. I need to reread it. Can you (or anybody lurking here) do anything towards finding a way to implement what I described in post 1134? http://www.cnczone.com/forums/showpo...postcount=1134
This looks less painful than direct measurement and has the bonus of being able to do tests with relatively small samples.
DAK, I've got a B.S. in General Engineering HMC '97 which makes me just knowledgeable enough to be dangerous. I usually work writing software so this is a nice chance to relearn some physics and chemistry.

DAK, Can you please examine the attachments at the bottom of this post and tell me what you think?
http://www.cnczone.com/forums/showpo...postcount=1129

They describe a silyating agent from DOW Corning called 3-glycidoxypropyltrimethox-silane that I was calling non-dangerous. It is one that has as applications directions that a few ml is mixed in lots of water with a bit of vinegar for PH control and then the aggregate dunked. It's an aqueous dispersion of some kind of silane based compound, not gaseous silane and it doesn't ship hazmat. Oldschool silanes were bad. With a flashpoint of over 100C, I think this stuff is safe if you don't drink it or use it as a lubricant.

Look forward to talking with you all soon.

<h4>
Anybody on this thread who has done experiments and can describe what they put in and obvious flaws in the results, please do so. It's vital information. If it's already on the thread, I'll find it when I index that section but compositions and observations for each sample beyond a picture and a smiley are the most helpful. Also, the exact order ingredients were added in to the mixture and how they were mixed should give lgalla an opportunity to tell us what needs to be done since I'd bet this is part of the tricky part.
</h4>

[mholden]

I am sorry if this has been brought up before. Milltronics used E/G bases on machines the largest is a 30 x 100 inch. They worked very well but cast iron is much cheaper.

[mholden]

sorry here is the pict.

[harryn]

Hi, some newbie comments here, on this very interesting thread.

Silane based adhesion promoters - there is a lot of history on these in many fields for bonding Si / SiOx compounds to organics. They work. I still think of them as sort of like primer for paint, but that is simplistic of course.

If you are not so comfortable with using these, at least a portion of their value comes from the chemical displacement of strongly adhering water films on the sand surface, even after baking. A final wash of the sand / filler materials with pharmacy grade 91 % IPA (rubbing alcohol) often provides much of the same benefit. Mild heating will evaporate the IPA away if needed. (outdoors of course)

Safety - please be very careful with silica based fillers, including quartz. These are well known for causing lung problems from inhaling small silicon oxide dust particles. For some reason, AlOx containing particles do not seem to be as much of an issue.

[walter]

Hello and welcome to the coolest and most entertaining thread ever!

Now you have the chance to be the reason that it continues to exist.

Simply visit this poll and cast your vote!

http://www.cnczone.com/forums/showthread.php?t=37019

Voice your opinion on this thread and tell us how we're doing!

Thanks :-)


( votes are anonymous, single choice, 18 or older, void where prohibited..)

[hotponyshoes]

I do a lot of work with caarbon fibre hence I know a little about getting epoxy to impregnate..

So of the items that are too large to go into an autoclave (or not wort the claving cost) get vaccum bagged.

This gives you a (in theory) a maximum pressure of 1 bar hence DOUBLE the pressure on your component.

You can normaly bag up any size component and draw the air out then place the whole lot inside another bag (needs to be glued or zipped together) and connect this to a air compressor, Even made from 'normal' materials these bags will take 2 bar so you can have a pressure on your component of (relibabaly) 3.5 bar.

Depending on what you are trying to compress you can squash stuff down nicely.

Onw word of warning, We have tried using high-freq and also ultrasound waves to get the resin to impregnate better.

It does seem to work but when stress testing ALL the parts we made with these methods came out weaker. Our resin guys think the waves prevent the resin molouculs bonding correctly.

For 'gluing rocks' I would starp a concrete poker (or several) to the outside of your mould and make sure you turn it off before cure commences.

[ckelloug]

hotponyshoes,

Glad to have you aboard. Interesting about the high frequency and ultrasound. I'd have figured you might have got the carbon fiber to resonate and damaged it rather than messing up glue chemistry. Interesting!

To the other denizens of this thread, I have indexed the 295 points I believe to advance the state of our knowledge rereading all posts from 1 to 1152! I'll publish the index tomorrow and begin writing the E/G handbook based on what has been learned so far.

[Stepper Monkey]

Hey all, I just got a big granite slab to make an epoxy surface plate out of, but more importantly I found a good source of nice thick granite slabs, dirt cheap, that you all might be able to use;

I couldn't afford an actual big granite surface plate, so I just got a big slab of polished granite. I couldn't find one thick enough from the kitchen counter making guys, but they suggested a place where I could get a nice thick one for next to nothing.

I did - and other than it is, well, kind of tombstone shaped, and has some dudes name and a date sandblasted into it on one side, it's perfect. The epoxy should fill that nicely though. It is otherwise a perfect granite slab for the purpose. Nicely flat and mirror polished both sides, and really cheap too! Guess there isn't much of a secondary market for "scratch and dent" factory rejects on headstones... I'll let you know how it turns out!

[thkoutsidthebox]

Hello, All
I have finally read all posts. Whew!!

I just finished the first 40 posts....maybe there's hope for me yet, but quite a way to go! At least now I know what polymer concrete is...

[DAK3333]

Harryn, In post #1150 you are dead on for everything. Gold Star.

Igalla, I believe you were waving the vacuum banner very early on. We definitely need vacuum and will get better results from it than vibration. As the lifting force of trapped air is removed the compressive force of gravity will be predominant. Pulling vac on the final mold may be impossible for some of the larger machines envisioned here, but just applying vac to the batches before the “pour” will go a long way.

Bob, I often miss the mountain while studying the mole hill, and have found that often it’s the guy who rolls up his sleeves first that receives the fame and fortune. Inquiring minds want to know, but those who go do it, win.

Walter, Zeosperes are nice. They are trade name for a group of materials called zeolites. Zeolites are lattice cages of either SiO2 or AlO, and are typically treated with some compound of interest. This compound of interest becomes trapped in the pores of the lattice, becoming “a ship in a bottle”. Usually these are catalyst or UV degradation inhibitors, theses ships in a bottle are then added to paint and coatings as stabilizers or hardeners and curing agents. Here in this thread we are treating them with epoxy, they then become beads on a string if you will. The fumed silica and carbon black (“Bling”) then are used as wheel chocks to keep the beads from spinning. This is as from post #early like the lava rock only on the micro level. What we need to do is limit the degrees of freedom inside the matrix of the composite without creating a brittle structure. Zeolites fumed silica, silica gel and large aggregate such as sand and gravel are all part of it.

Ckellouge, speaking of the micro level, that is were I feel comfortable. However you deal with macro forces and dynamics, and as we all live in the macro world your input will become more necessary as we reach a final formula.
The small samples you talk about are very important for materials study. I use a TA Q800 DMA to analyze samples of my material (usually 50mmX10mmX2mm) PDF attached. TA publishes an application guide form time to time, perhaps they would like to highlight our work. I personally would love to test some samples but Uncle Sam would frown on that use of taxpayer $$, and as a fed I cannot endorse TA or approch them.

Greybeard Walter and Bob in the interest of K.I.S.S. I suggest that since we are already using quartz, fumed silica and sand, all of which is predominantly SiO2, that we should not pursue the use of silylating agents. Ckellouge, yes there is an increase in strength but the added complexity of steps may not be value added.

It has happened, I have left someone out, sorry it is not intentional. Just a side note though, this is the first thread (or forum for that matter) which I have ever posted to. I came to CNCZone looking for info on a small PCB Mill, found this thread and felt welcome enough to try and make a contribution. Thank you all for such a welcoming atmosphere.

[ckelloug]

Dak3333 Your last post is remarkable. The dispersion hardening info here comes mainly from references to rubber hardening chemistry that I don't know how to find documents on. Your experience will prove invaluable as you are certainly the first expert on the chemical properties of reinforcement which is where we are. Are you sure you don't have an epoxide group hanging off of you? You've bonded nicely with the group! Please stick around as many of us will have zillions of questions.

Fun statistics. I've produced a poster histogram of the index of the thread I'm producing. This index covers about 300 of what I deemed the most interesting posts between posts 1 and 1150 or so and attached it for the sake of humor.

<h5>Any volunteers to help edit the CNCZone E/G E/g E/Q handbook?</h5>

[walter]

...for a group of materials called zeolites. Zeolites are lattice cages of either SiO2 or AlO, and are typically treated with some compound of interest. This compound of interest becomes trapped in the pores of the lattice, becoming “a ship in a bottle”. Here in this thread we are treating them with epoxy, they then become beads on a string if you will.
The fumed silica and carbon black (“Bling”) then are used as wheel chocks to keep the beads from spinning. This is as from post #early like the lava rock only on the micro level. What we need to do is limit the degrees of freedom inside the matrix of the composite without...

Now that's what I call hard core!



I’m very proud of the team that we’ve managed to assemble. If we don't get to finish that battlecruiser now, my head rolls first ---> (chair)

Thanks for being here! :cheers:

[ckelloug]

Here is a section from the handbook I have started writing for us to use on this thread by compiling everyone's posts and calculating what needs to be calculated:

E/G is a heavy material with a density of about 125lbs/ft^2 with
tensile and flexural strengths of about 2ksi and a compressive
strength of about 10ksi. It has tensile modulus around 2000 ksi and
compressive modulus around 4350ksi. These are midpoint values for a
nist paper on E/G: brunog [935]. These are from material that can be
assumed well made commercially. There is virtually no hard data as of
May 4, 2007 as to the material properties of the composites made by
thread members.

Consensus is that a 192x96 inch footprint gantry router is the biggest anybody here would be interested in producing. The smallest seems to be about 12 inches in footprint. Since not all thread members are engineers,
this section aims to provide some guidance into the sizes of structural members used in making a part.

Here are some rules of thumb for 100 lbs load plus beam weight for estimating the size of the top beam of a gantry. These calculations use 2e6 psi for flexural modulus at a safety factor of 6 for simply supported beams i.e. beams that are supported with both ends sitting on something.


The figures in this first table apply only to carrying the load and beam weight, not to deflection.

0-12 inches: 2inch x 2inch beam sufficient
0-24 inches: 2.5inch x 2.5inch beam sufficient
0-48 inches: 3inch x 3inch beam sufficient
0-96 inches: 5inch x 5inch beam sufficient
0-192 inches 13inch x 13inch beam sufficient

Smaller beams than these may self destruct in use.


The next two tables cover simply supported beams considering deflection:

For Unreinforced E/Q considering the weight of the beam plus
100 lbs at .0001 deflection at midpoint

12 inch long: 4inch x 4inch beam required
24 inch long: 8inch by 8 inch beam required!
48 inch long: 25inch inch x 25 inch beam required!!!
96 inch long: Unachievable
192 inch long: Unachievable


For Unreinforced E/Q considering weight of the beam plus 100 lbs at
.001 deflection

12 inch long: 2.5inch x 2.5inch required
24 inch long: 4inch by 4inch required
48 inch long: 8.5 inch x 8.5 inch required !
96 inch long: 30inch x30inch required!!
192 inch long: Unachievable

Examining the data: It looks like the easy unreinforced E/G will be very nice
for machines up to 24 inches square in foot print as a 24 inch beam
can be made with .0001 deflection with 8 inch cross section. Larger
machines will definitely need to use some sort of reinforcement or cored construction as they will warp too much to be very good.

Assuming we get better at making E/G, machines smaller than 24x24 should be easy to do. This is excellent news because it should eliminate the doubts we had about this all being possible.

Big machines will need a lot more engineering.

[walter]

Well, the Caveman Lab is now open for business..










I will try to attempt to answer some of the epoxy content vs strength questions.

If I don't come back in 6 hrs, delete your links and pour a little 90 proof liquor on the pavement for me.. :tired:
_

[brunog]

I got information from Epoxytech, they manufacture East system epoxy.

They suggest we use their epoxy resin and hardener 9482 which is actually intended for marble repair and aggregate bonding.

Ihave attached the specs. Does anyone have any idea what a shore D hardeness represents in compressive strength??

Best regards

Bruno