[lgalla]

Directions
Lar

[walter]

Torch and heat lol! that thing almost caught fire yesterday

Larry, how's the exotherm on this thing.. I've got it at 1/4" now (at 68 deg F )

(thanks for the PDF!)

[jhudler]

Larry,
I know they say it's "self leveling" but this doesn't mean it's flat. What are the expectation of the Table Top's "level" err "flat" +- .005 ? Do you know?

Would be nice to know what's in the TT but they don't have MSDS online.

Jack

[walter]

Ok, I've got it under control. I also found the cause of the meniscus. It was the stupid fan! I've had thermal runaway and I pointed the fan at the center..

Sorry for the chaos. This 150 lbs plate was built with E/G, aluminum junk and rocks and is for one time use only- to cast the machine table.

http://www.cnczone.com/forums/showpo...postcount=1137

Bob Warfield's table. I'm going to glue the inserts to the surface plate and then pour E/G.


Max,

I bought the el cheapo 1/4-20 inserts from this store http://www.mcfeelys.com/search.aspx?q=insert $26 per box of 100. I'm just testing the idea, don't feel like spending too much on it.


John,

Sorry for the chaos. This time I think it was my fault.


Jack,

The plate is over 2.5" thick, 150lb and rock solid. TT epoxy with no fillers.


Larry,

Thanks for the info and the help line. I really appreciate it!

[lgalla]

Walter from the shopmanic site, you calculate the volume/sq/ft for your pour.If you use a torch or hairdryer the viscosity goes well below 100cps.The hair dryer will blow and ripple the heated ,lower viscosity epoxy.Rather than just repeating or quoting the Pdf,read it over and over again.
You must also level the part to be poured with even a simple carpenters level.
Jack we are relying on Precision epoxy's success at leveling floors for testing space robots.http://www.precisionepoxy.com/NPS%20plate.htm
Larry

[jhudler]

Max-Mod... your avatar on usinages.com is too cute. Keeps distracting me from reading.

[jhudler]

Larry, Walter,
I'm wondering if you should just try an cast this plate on top of piece of glass window pane. Using thickness spacers at the edges and center that you can fill in later... ala Moglice technique. You would have to deair the epoxy in a vacuum or ribbon pour. Spray a thin film of mold release and then use compressed air at the edges to release it after cure.

Glass made today is done using a process where molten glass is floated on top of molten tin, that's why it's called float glass and it's normally flat to about +-.005. Take a micrometer down to your local hardware store and see.

If you want really high quality glass the go here S.I. Howard Glass and look at Schott D263 Borosilicate Glass, it has surface flatness up to +-.0008". Schott Borosilicate has excellent CTE characteristics and won't warp on you or god forbid shatter you if things get too hot. Look at the Soda Lime Glass if you want something thicker to work with.

Comments?

Jack

[greybeard]

OK Jack, your mention of glass has now prompted me to show my hand.
I had hoped to get the idea built and tested first, but the kitchen refit for SWMBO has intervened, and it may be the New Year before everything is complete.

What I intend to build, based on my idea of using spin cast elements to construct the frame, is a small machine for wood routing(30in x 20in x 2in, XYZ), using a 1.5kW router that weighs about 3lbs, with air bearings floating on glass surfaces.
The beams will be triangular in section spun cast in EG, about 3in x 4in, but after casting and post curing, each bearing face is coated in turn with a thin layer of epoxy, and a glass strip is laid on top, two surfaces only on each beam.
The end product will use the glass surface embedded in the epoxy as a path for the air bearing which will be made from porous carbon filter elements.
These will be cut from 10 micron water filter cartridges, each giving a 4 sq. in bearing area, so I'm planning to use them in pairs, spaced appropriately for the length of each truck.

I'm designing in CorelDraw, so I'm afraid the drawings are fairly basic, but I'll add a view to this post for starters.
When I get into testing the air bearing design, my next step, I'll start a thread for the whole project.

John

[the4thseal]

ok what does "SWMBO" mean? s for the bearing......i do not get it......at least how it will work. i would love to get it and i hope they work. i have seen air bearing and they are cool.

[Mcgyver]

SWMBO = She who must be obeyed. Not very familair with the term myself, being a caveman and all

[the4thseal]

it appears i need to make a man hut as a bastion safety. thanks

[harryn]

Walter from the shopmanic site, you calculate the volume/sq/ft for your pour.If you use a torch or hairdryer the viscosity goes well below 100cps.The hair dryer will blow and ripple the heated ,lower viscosity epoxy.Rather than just repeating or quoting the Pdf,read it over and over again.
You must also level the part to be poured with even a simple carpenters level.
Jack we are relying on Precision epoxy's success at leveling floors for testing space robots.http://www.precisionepoxy.com/NPS%20plate.htm
Larry

Hi Larry

The targeted location for my DIY router has a floor slope of about 1/4 inch in 3 ft, and it has been a PITA to work with the build in that location. (The whole garage is sloped, so the exact location does not matter) This is a particular problem for me, as my router has no table - it builds up from the ground.

I have been toying with the idea of leveling the spot out using an epoxy surface plate, and wondered just how level it would end up being. After reading the entire article on the Naval Academy installation (2 X) I saw that the "spec" listed by the author was +/- 0.003 "foot to foot", and it still had a bit of a slope when they were finished. This seemed "ok" but not as good as I expected given what has been discussed on this thread.

I called Precision Epoxy today to discuss - a couple of interesting points:

a) Static - they use the Cu tape with good success to dissipate static. That was a big deal for me as well.

b) The spec for that NA application was +/- 0.003 in over the ENTIRE 14 x 16 ft floor - not foot to foot as the author had listed. It turns out that that floor had some very serious problems - cracks, humps, shifting, etc. In any event, they went back and did a "repour" to fix it and it is now dead on.

c) There is a minimum amount of material needed in any given "layer' to level it out. The minimum thickness over the highest spot is usually 1/8 - 1/4 inch, with 1/8th usually being plenty.

d) Over my 3 x 6 ft area, the PE guy thought I would have a hard time to measure ANY variation from dead flat when I am finished. Pretty impressive - almost as good as my hand sanding.

e) The "original" purpose of the product was for machine bases, but the NASCAR market came along faster. I think he said it had a T Strength of 18 KPSI but I am not certain right now.

f) Al part leveling - - We discussed the idea of pouring a layer into a piece of Al channel 3 in wide x 8 ft long to level out the inside - no problem - should be very level.

g) BTW, it also has de-airing aditives in it now.

g) Pretty much anything can be used as a mold (2x4, melamine, etc), the top coat is not needed for machine bases (just a gloss coat), there is not a need for a ramped edge for a machine base, and he is sending me more info.

Anyway, it looks like these epoxy materials can definitely be made to pour flat. I suspect that he has additives in it that reduce the surface tension as well. I wonder how it would perform as an epoxy for EG ?

[lgalla]

Harryn,good you talked to the precision guys.Answered many questions for me.
Good luck with the floor.I like the idea of using the floor as the tabletop with no legs.Can't get any more solid than that!Only problem you have to bendover for loading or tool changes.
Larry

[greybeard]

.......and for dogs chasing the spindle.
John

[jhudler]

Question, is this attempt at creating an epoxy surface place, just so you can place linear rails on it?

[lgalla]

My shortest post ever,Yes for my application!
L

[harryn]

For my goals:
- I would like a flatter work / assembly area in general, so anything is better than now. For various reasons, my workbench isn't that flat or large, and it has a bunch of kids projects on it. I guess that is ok from a macro viewpoint.
- My spindle will be horizontal (z) and the Y axis is vertical, so I can change the tooling at any height (yes it reaches 6 ft off the ground)
- My router project is being built inside of a cabinet from the start, so hopefully, at least part of the safety question is dealt with.

Getting the area more level got started when my cabinet legs did not have enough range to level the cabinet. I am marginally competent in the first place, so building something straight and squre on that much slope has been challenging.

Of course, all of this work is still some time in the future from reality.

[harryn]

d) Over my 3 x 6 ft area, the PE guy thought I would have a hard time to measure ANY variation from dead flat when I am finished. Pretty impressive - almost as good as my hand sanding.

LOL - I forgot to tell the guy I sell equipment that measures the flatness of of semiconductor wafers much more accurately to flat than the curvature of the earth - while they are moving Of course, I probably don't need that level of precision for wood cabinets.

[lgalla]

In the jist of trying to keep it short.I will only respond with one sentence.
Yes,I want an epoxy surface plate to mount the linear rails to to guarantee a level vertical plane only having to worry about the horizontal rail spacing which will also provide an accurate surface to measure and align the Y axis rails which are mounted on the Y axis steel beams which were cast from the surface plate of the tabletop and know X&Y are true and Z is a piece of cake and the steel beams can be modifyed or filled with epoxy/granite to eliminate symphatic resonances and if it ain't true one can just mill the spoilboard or tabletop into perfection with theYaxis which will result in one happy CNC Camper.
L

[jhudler]

How about building a flat torsion box and then level it.
I do all my woodworking assembling on one that measures 4x6 feet made of 3/4 MDF with a hard replaceable Masonite inlay.

For a level surface you only have to level the box with adjustable feet.

You must have a well aligned table saw to make one: blade parallel to guides that are parallel to the fence, and blade that is square to table.

A torsion box would be an excellent surface to cast EG parts on.

Google "torsion box"

Jack