[JerryFlyGuy]

What about using the sand that is a from water jets? Not as the sole material but as a portion of the aggragate?

Better known as Garnet, the same as is used [basically] in sandblasting.

Jerry

[Geof]

What about using the sand that is a from water jets? Not as the sole material but as a portion of the aggragate?

Judging from a thread I read a while back you should be able to get this for free after it has been used. And you would have a heck of a time drilling into the finished material.

[JerryFlyGuy]

Larry asked me to post this PDF for him, it better explains how he planns [is?] to build [ing] his router.

Jerry

[lgalla]

In reply to Atenman1,
My business is making money[Hopefully]Company motto"We do anything for money".Actually the main focus is woodworking.We had previously had much involvment in composites from aircraft parts to poured counter tops.Right now the project is"Sub contractor"We designed huge subwoofers for the club&concert market.Our designs are for large companys who put their name on the product.
On the granite machine cuttings and used sandblast sand,I would assume you are getting lots of impurities.Sand is only 5bucks a bag.Why take a chance?
Larry

[CNCAddict]

Larry, wouldn't laminating resin be much better? The epoxy you linked to is "thick" epoxy. Would it still flow enough to provide an extremely flat table surface? Also, 0.005" can't be a hard and fast rule. I'm sure it would be possible to do better than that with low viscosity resin, no???

Keep up the good work

[lgalla]

Fellow CNC addict.Was the linkwww.shopmaninc.com?If so look in more detail they have 600cps laminating epoxy in various pot lifes.Also check their TT epoxy.[table top epoxy]very good how to's.This is our surface plate.
On Walters'channels[must add good idea]I assume the frame will be levelled with a level first.The final pours for"plate"in my opinion should flood or pour over the edges.This makes a huge mess but is necessary to self level.
My 2:cheers: worth
Larry BTW Walter how is the frame assembled?

[brunog]

Larry,
Just finished looking at the PDF file Jerry uploaded table looks good.

Question: would you not haave better vibration damping if the slides were set further on the inside and were fastened on the E/G base and not on the I beam.

What do you think?

Bruno

[walter]

Atenman1 & Bruno,
Thanks for the links -lots of good info there. Keep them coming!



CNAaddict,
Half inch "second pour" - that is a good idea, check out the "precisionepoxy" link for more details- beautiful surfaces there.



Larry,
About the frame assembly: Very simple design, 3 piece E/G "bolt-on" gantry in the middle of the frame. The whole thing floats on the steel stand. That's the whole router. (more drawings on Sunday).


Thanks for all your help & suggestions- much appreciated!

[vger]

My brother works at a granite shop (counter tops) and they have lots of scrap stuff they would just love for someone to haul off. Lots of small pieces that could be crushed up. Might check with a local granite counter top shop to see what they have.

In handling the granite surfaces (2 and 3 cm thick) they use great care to avoid breakage. They even have special metal rails with vacuum hold downs to ensure rigidity for transport. If you attempt to support 6 ft or longer 3 cm thick piece at its ends, it may break. Not sure if this would be true of E/G.

The mold release that was refered to on the http://www.microplan-group.com/pagin.../celith_gb.htm web site may well be a product called PVA (Poly Vinyl Alcohol) in either a liquid or paste form. I've used PVA as a release agent for polyester, vinylester, and epoxy materials with good results. It's not very expensive, cleans up easily, and it does have a reasonable shelf life.

The microplan site also mentions they incorperate T slots into the structures. Might make for an interesting demold. I would assume you either slide the T out, or perhaps the T is made of something soft enough to be easily removed.

Have a great day
Steve

[brunog]

Vger,
I believe they insert metal T-slots when molding, the info was much clearer on their french version.

Bruno

[oldpoopie]

Couldnt you use a syrifoam of some sort to mold with. Then any areas difficult to break free could be melted out with a solvent.

[lgalla]

Hi Brunog,
The slides are mounted this way as it is near impossible to drill the E/G.I don't think the mounting location would make any difference as the steel flange is only 2"wide.Thanksfor the comments.
Steve I agree large unsupported slabs would probably break.In my table made of I beams it is self supporting without the E/G.The E/G is only for vibration damping and surface accuracy.People making mill bases are probably in the 18"X24'X4"no problem.
PVA is great,but I never have much luck spraying it.Must try the paste.PVA is water soluable.If your part is stuck you can pour water on the mold part line, the water will work its way down and aid in release.
Steve could you ask your brother a source for drills for granite?
Thanks
Larry

[brunog]

Larry,
if you position threaded inserts before pouring in the E/G no drilling is required.

(please refer to post #30 in the thread as an example)

Long hex nuts with hex bolt inserted 1/2" and sticking out at the bottom could make a good insert. Adding a large size flat washer could give it more strength.
Then plug the insert holes before applying the final leveling coat of epoxy.

Voilà, no driling on E/G
Bruno

[JerryFlyGuy]

Or, just D&T into the beam, then install removable tapered studs into the holes, the studs are narrower where they face up to the beam than at the top, a little wax and a simple twist they break loose from the epoxy and screw out leaving you w/ a tapped [& counter bored] hole. Most rails have very accuratly placed mounting holes so it shouldn't be to tough to do. My rails came w/ 60mm c-c holes. You still have to get the suckers straight, but thats another discussion

Jerry

[vger]

Hi Brunog,
Steve could you ask your brother a source for drills for granite?
Thanks
Larry

Here is a link to one site that has em...
http://www.diamond-drill-bit-and-too...Drill/MAIN.htm

They use the core drills as most of their holes are relativly large. The same site has some tips on using them, as well as other diamond tooling. His shop has a nice CNC machine that does the edges and the cutouts in the countertops. Fancy edging tools like these..
http://www.granitecitytool.com/showi...=37&pcatnum=80
Some of the profiling tool bits they use are > $600 ! They last quite a while as long as they keep em wet, real wet :drowning:

I've used the diamond core bits to drill through glass. Just keep the feed rate real slow, keep em wet, and back em out frequently to cool and flood with water and they work great. On heavy granite once you are deep enough for your insert or whatever, just do what the Egyptians did, snap the center post out. http://www.geocities.com/unforbidden...ng_drills.html
Just use lots of EG (elbow grease)

Steve

[lgalla]

Where is Mark aka RotarySMP?Mark provided many good leads and technical info.
From all the good pictures provided it appears a solid E/G gantry is best suited to mills and moving tables.
On my I beam table,I do not want to use inserts as I worry of getting it right the first time.The I beam allows more trys.
For the mill guys a solid granite surface plate 18"X24"X4" can be had for $45.If this could be drilled and or inserted this should make a cheap solid base to build on.
Larry

[brunog]

Larry,
have you considered slotting the ends with an angle grinder and diamond blade and inserting a piece of flat iron between the granite surface plates?

Bruno

[lgalla]

Bruno thanks for the ideas.there has been many good ideas worth weighing or considering or incorporating to the final design.This thread seems to be dying now as posts are few.I am dissapointed as the ideas were leading to a simple solution for accurate machinery for the home guys or semi pros.
What happened to the burried 80/20?Not for me but interesting enough.I try to post as check this out or read this.I try to post as think about this.Thanks to members "checkin it out"Maybe members in general want to be told buy this epoxy buy this aggregate mix this ratio etc.If one is serious about a build one should read all posts from#1 and seek advice or input to ideas.Nobody is an expert on this new technology and we can acheive expertise by combining
ideas.I am 99% sure of the route to take for my build,but still like or desire more ideas.Come on guys lets put our heads to-gether and find good solutions.
Larry

[walter]

...Any how I figured out a slab of real granite is 1/2 the price of epoxy granite,maybe less...

Hmm...
How about using some of those kitchen 5"x2" granite slabs?
Should be relatively easy to put few of those "together" and encapsulate it with E/G...?

(This could work for smaller machines, up to 3'x5')

[brunog]

Bruno thanks for the ideas.there has been many good ideas worth weighing or considering or incorporating to the final design.This thread seems to be dying now as posts are few.I am dissapointed as the ideas were leading to a simple solution for accurate machinery for the home guys or semi pros.
What happened to the burried 80/20?Not for me but interesting enough.I try to post as check this out or read this.I try to post as think about this.Thanks to members "checkin it out"Maybe members in general want to be told buy this epoxy buy this aggregate mix this ratio etc.If one is serious about a build one should read all posts from#1 and seek advice or input to ideas.Nobody is an expert on this new technology and we can acheive expertise by combining
ideas.I am 99% sure of the route to take for my build,but still like or desire more ideas.Come on guys lets put our heads to-gether and find good solutions.
Larry

Larry,
I totally aggree with you, I also believe that E/G is the way to go in building a good solid machine. I am far from being an expert in this domain,and I am trying to find good quality low cost possibilites in aggregates and epoxies.

So far filtering sand looks like one part of the puzzle as its content is 100% quarts, however i want to learn more about what are the correct sizes of aggregates to use?
Would glass beads be feasable as an E/G component?
also you have mentioned 1/32" glass fiber for reinforcing E/G,that also looks interesting. How about aquarium stone? too big?

Another concern I have is about molding:
Is there a simpler and efficient way to make E/G casting without having to build a vibration table can I make multiple pours and force it in the cavities wit a trowel? Canan electric sander do the job as a vibrating pad over the E/G paste to improve the final product provided it is well protected against the epoxy ruining it?

What about anti foaming additives anyone know more about this?

I am sure that all of the answers are somewhere and we need to continue discussing the process in this thread, we all have somekind of experience in different domains, I am sure we can come up with answers by keeping
our thinking caps on and loking different avenues.

regards,

Bruno