[lgalla]

Jsage we are not really having a dry humor contest.Strange,weird,humorous ideas lead to good solutions.It gets people thinking,new ideas evolve.It seems to promote members posting what they may think is crazy ideas but the proof is in the puddin,we have 426 good informative posts.As far as I am concerned the dry humor posts have helped to discouver new ideas.I hope any dry humorous posts have a buried serious note.
Thanks for all the good posts.
Larry

[jsage]

LOL,

Cheers Larry, and all. I'm going back to my own mission for now.

mike

and the sage is short for sagebrush. Not like I usually have something sage to say ; )

[walter]

This is longer than waiting for 8' thk's to appear on E-bay...

You're after them as well? I have a feeling it'll be a long wait..

[lgalla]

Walter actually ther has been long rails on E-bay.To-day SR15's 101" long went for $600 a pair.A guy had 10 sets HSR45's with 36 ft of rail and 4 blocks.Some went for $200.He would not ship to Canada so I lost out there.I will PM you if anything good comes up.
Larry
PS It is probably better to just buy HIWINS in the size you need.

[walter]

Good info. Thank you.

[brunog]

The downside is if you want to vacuum clamp through a MDF spoil board 4'X8' the vacuum pump must be 15hp or confined to purpose confined hold down areas,resulting in slower production rates.

How do you intend to secure the spoil board?
If i understand correctly you need 15hp to suck through the MDF?

What if you make grooves that would be in line with the vacuum holes,
would you need less hp then?

If your concerned with having to allways use vacuum on 100% of the surface, there could be ways of making simple manifolds and using ball valves to concentrate vacuum where it's needed, and maybe not use so much HP?

best regards

Bruno

[Zumba]

You can secure the spoilboard to the table with the vacuum grid. The vacuum grid can be molded into the E/G table itself. That would save a heap of money over machining a solid aluminum 4x8 plate. Aluminum and E/G theoretically have the same density, and theoretically have a 15 times price difference ($5.00/pound for aluminum here in Northern CA, 30 cents for E/G).

Also, when using a spoilboard, perfect flatness of the E/G table is unnecessary. The self leveling nature of the epoxy should give sufficient flatness.

[martinw]

Testing, testing

Has the cnczone server gone "clunky" ????

Martin

[greybeard]

Yes, for the last twenty minutes, on and off !
John

[martinw]

The density of polystyrene and strength is of little use in E/G,urethane is the way to go.
Larry

Dear all,

I think there has been some trouble with the server. Hence previous test transmission.

Anyway, could we return to Bruno's ripping idea of casting-in rigid foam panels briefly, before the whole caravan moves on yet further?

I totally agree that expanded polystyrene has little strength, but extruded polystyrene (eg some grades of Dow's Styrofoam) can have compressive strengths in excess of 70 psi. However Styrofoam has a coefficient of linear thermal expansion that is eight time greater than granite, and this might cause problems.

I had to insulate a high temperature in-line air heater battery a while ago, and was worried about the insulation melting (or worse). The stuff we used is called FOAMGLAS It is glass that is "blown" into a foam using an inert gas.

There are various different grades available but one of the strongest is HLB 1600 which has a density of 10 lb per cubic foot and a compressive strength of a whopping 232 psi. It gets better....the coefficient of linear thermal expansion is absolutely identical to that of granite.

OK, compressive strength is only part of the picture, but to put it into perspective, you could build a solid brick wall 300 feet tall with the bottom course of bricks replaced by this foam.

Here is a link to Foamglas (structural properties are on page 16)..

http://www.foamglasinsulation.com/literature/FI201.pdf

It might be worth looking into.

Best wishes

Martin

[martinw]

Yes, for the last twenty minutes, on and off !
John

Dear John,

Twenty minutes! You were lucky!

More like three hours from my neck of the woods.

Best Wishes

Martin

[jsage]

martinw,

Will definitely give it a read. Checked the first couple of pages and was intrigued. Gotta run.

One semi aside. If the overall engineering is good, then perfection of the epoxy granite fabrication becomes less critical.

[greybeard]

Martin - your mention of foamglas put me in mind of a product that is/was used as a polyester filler, hollow glass spheres. Can't drag the memory back, but it might have been called something like "microspheres"? Poured like dry sand, and got everywhere when I tried it about 30 years ago !
Obviously a possible low density substitute for the sand rather than for macro inserts like your foam blocks.

John

[Geof]

Martin - your mention of foamglas put me in mind of a product that is/was used as a polyester filler, hollow glass spheres. Can't drag the memory back, but it might have been called something like "microspheres"? Poured like dry sand, and got everywhere when I tried it about 30 years ago !
Obviously a possible low density substitute for the sand rather than for macro inserts like your foam blocks.

John

Maybe a low density substitute but not a low cost substitute.

http://www.fibreglast.com/showproduc...llers-111.html

$66 for 3 lbs, about one cubic foot.

[lgalla]

Hi Martin I was out 4or5hours.I was worried my bad puns got me kicked off the Zone.
Larry

[martinw]

Hi Martin I was out 4or5hours.I was worried my bad puns got me kicked off the Zone.
Larry

Larry,

You cannot escape your challenge to me of a duel over bad puns so easily, and by blaming the CNCZone server. It is a matter of honour, probably conducted in mist-shrouded woods, at dawn, with PCs at 5000 miles apart.

Best wishes

Martin

[lgalla]

Hey Bruno& Zumba back to the vacuum table.
If you are high production,you do need 15to20hp vacuum like the big boys sucking through MDF or LDF.They gurantee holding one sqft with the rest of the table open.Naturally Zoneing reduces the requirements.As I have a small 15cfm pump I will experiment with it.Perhaps a vacuum storage tank would help.An aircompressor tank is not suitable as it will collapse under vacuum.Really!
Zumba I have not studied the grid table so am dumb on the subject.As a first project for your router could you attatch a solid plastic sheet to the top and rout the slots???Rather than trying to cast the grid.
Larry

[ger21]

If you are high production,you do need 15to20hp vacuum like the big boys sucking through MDF or LDF.

Not necessarily. If you are running lots of the same parts, a dedicated fixture will let you get away with very little CFM, provided you get a good seal. But if you want to cut out sheet after sheet of varying nested parts, than yes, you will need to be sucking through a spoilnard with a high CFM pump. Be prepared for a LOT of noise from that pump, too.

[lgalla]

Right on Gerry,could naw said it better myself.Great spelink Eh!!
If you plan a router for high production you have to be prepared to possibly spend 8 grand on a pump.
Gerry a sales guy once told me besides the noise."If you have a 3000sqft shop and a 15 to 20hp vacuum,you will need air conditioning in the summer and no heating bills in the winter"I guess they produce lots of heat???
Larry

[ger21]

Not as much as our 50HP compressor. runs at about 190°