[eloid]

hello doing some research for a vacuum table, I would like to build
and make it modular as time needs ( 2x2 panels), to eventual be large enought to hold down 4x8 sheet.

i seen the vacuum pumps at harbour feight not sure if they have what i need long term...can anyone tell me how many inch or hg or mircons typical one needs
etc for large hold down claping power....

would this do

http://www.harborfreight.com/cpi/cta...112&zmap=66467

or

http://www.harborfreight.com/cpi/cta...emnumber=66466


Is the rating of microns enough? I think i would need to have a inline vacumm tank.... to have reseiour on hand for the pump to catch up if there
leakes etc...

[Harrymac]

Try building one Go to JoesVenier.com not sure of spelling .I just built venture type for shop runs many presses, clamps etc for uner $200.

[rcpilot82]

www.joewoodworker.com

Venturi Press and electric pumps

[rowbare]

I don't think that pump will hold down a 4x8 sheet at least not in a general purpose application. If there is any leakage whatsoever it will release. MDF tends to be porous once surfaced so if your work piece is MDF you might have some issues.

As for a vacuum tank, all that really does is increase the volume that you are trying to evacuate. That isn't to say it can't be useful, but you need some clever valving. The idea is that you evacuate your tank, use the vacuum from that large vacuum to suck the part down, then switch to the pump once the material is in place.

However for special purpose applications things a couple of strategically placed vacuum pods like http://www.vac-clamp.com/ (or home-made ones, many examples on the site here) could do the job nicely.

[eloid]

I don't think that pump will hold down a 4x8 sheet at least not in a general purpose application. If there is any leakage whatsoever it will release. MDF tends to be porous once surfaced so if your work piece is MDF you might have some issues.

As for a vacuum tank, all that really does is increase the volume that you are trying to evacuate. That isn't to say it can't be useful, but you need some clever valving. The idea is that you evacuate your tank, use the vacuum from that large vacuum to suck the part down, then switch to the pump once the material is in place.

However for special purpose applications things a couple of strategically placed vacuum pods like http://www.vac-clamp.com/ (or home-made ones, many examples on the site here) could do the job nicely.

from my understanding vacuum is vacum, 29 inch hg is top end, and anymore is not worth the money to spend on it, at 9 cfm that a lot of cfm to evacate... that where the differeance lies ... the time it take to evacute the give area... the 2.5 3.5 cfm unit are will take 3/ 4 times longer to do evacute same area...

In my application I would use a 4x 8 vaccum table that had ported ports which would accept pods simular to the nemi pods ie diy version of them the pod you showed are ok but lack the versatility of the Slider Pod see the below links

The task is to hold down 4x8 sheet of oak partical brd with pods or specifically locateded mats ...anything less in my opinion would only vacuum in a lot of saw dust into the filter/ vac system of the vacuum pump ..what I plan on doing is using pods or several vacuum pads/ mats to achive the vacuum for this task. The tank is mainly for power outages or poped breakers... if a breaker goes on the vac system during milling ie Reserve tank would be a safty feature or for big leaks.. nobody needs object fly out of there cnc machine cus of a thermal overload issue on a vacum pump.... if being run continouly with out vac tank.




[ame="http://www.youtube.com/watch?v=X6hVL9bomh4&feature=related"]YouTube - Two Minute Setup![/ame]
[ame="http://www.youtube.com/watch?v=SfvQoQnQgmQ"]YouTube - The versatility of the PATENTED NEMI Slider Pod![/ame]
[ame="http://www.youtube.com/watch?v=7u01h7ffQ8M&feature=related"]YouTube - NEMI Mushroom Clamps![/ame]

my question is the quailty of Hf pump any good?

[eloid]

Try building one Go to JoesVenier.com not sure of spelling .I just built venture type for shop runs many presses, clamps etc for uner $200.

how many cfm can you get? how many inch of hg can you pull? is it a pump version or venture type?....
hf has unit 3 cfm $159
9 cfm $249 hard to beet that price both units....
if you dont want to built one ie time...

not sure if you save long run vs all the extra work required. There great for
r134a ac car repairs and home ac systems.. has the fittings for evcutating
ac systems.

[ger21]

At work on our machine which uses pods, we have a Becker pump like the $9000 one here. With 170+ CFM

http://www.shopbottools.com/vacuumholddown.htm
No way those little pumps will be able to work with multiple pods on a 4x8 sheet. You need very high flow, because you'll have leaks. Also, with out very high CFM, you'll have a hard time getting all the pods to suck at once, unless you have a valve and can open and close each one individually. The problem you'll have is that if one pod is not making contact, you won't get any suction on any of them. Also, Vacuum will suck through MDF AND Particle board. Which again means you'll need higher CFM to maintain vacuum.

[Benonymous]

I have a 4CFM version of the pump that HF is offering in 9 CFM, from your links. I'm using it for vacuum bagging. When I started off vac bagging I had a lot of trouble achieving a decent air-tight envelope and at one stage I ran the pump continuously for around an hour. My observation was that the pump body got quite hot and the pump oil started misting out of the air outlet. When I stopped the pump, I'd used quite a lot of the oil and needed to top it up. I'm really not confident that these units are suitable for continuous running as in a vacuum table situation.

As an aside, a friend who runs a commercial grade machine with a vacuum table has a sheet of 5mm MDF on the top and the vacuum actually pulls through it. So he's got a scratch surface and a dust filter in one!

[Harrymac]

eloid ; you can reach me at email I can go into more detail to buzy now to do working,[email protected]