# Vacuum Clamping



## woodapple (Aug 23, 2007)

Hi Folks, 

I'm looking for information on vacuum clamping set-ups for template routing and have found numerous websites describing different methods. The most attractive (cost effective) seems to be using an old refrigerator compressor as the vacuum source. Does anybody have any direct experience building and using a system like this? If so, I would like to hear your take on it. Thanks. 

Eric


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## Thom2 (Nov 12, 2004)

I can't say much about using a refrigerator compressor, but I'll show you my rig anyway.

here it is set up for use:










and here's a shot just to show the basic components:










FYI: One of the first pieces of equipment I ever bought for my shop was a 60g air compressor. My Dad was a mechanic/autobody repair tech for many years and I grew up having a large compressor in the shop. I do enough other stuff besides woodworking that I could never survive without a decent size compressor.

With that said, aside from the compressor purchase, this vacuum rig I built cost me $10 .... yes ... $10 ..... I know you can't believe it, I know you've been shopping and gasping at the prices of these rigs .... but I'm telling you ...... T-E-N D-O-L-L-A-R-S 

I will admit that I was lucky enough to have a lot of the pieces laying around to complete it, but the major component is $10 and miscellaneous hardware will set you back another $20 or so, plus a guage ... hmmmm ... you should be able to be into a setup like mine for under $40 if you play it right.


First thing you'll need to do is make a trip to HF to get the major component .. you know ... that super-whoppin' expensive T-E-N D-O-L-L-A-R component 

Super Expensive T-E-N D-O-L-L-A-R component can be found here:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92475

You can also pick up this guage from HF for $13 ... I think I've seen it on sale for under $10 tho'
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93547

Now you've got the two major pieces you'll need, go home and tear apart that vacuum pump, the only thing you'll need is the gut (in my picture it's the silver box smaller than a pack of cigarettes). Take the gut and head to the local GOOD hardware store that has a decent assortment of brass fittings. Do whatever you need to adapt the inlet to your air hose nipple (I later installed a ball valve on the input side). On the output side, you'll need a tee if you plan on running the guage. 

There you have it, now you know the secret to my inexpensive vacuum rig


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## gregW (Mar 14, 2007)

that's pretty cool Thom...thanks for the info.

are you using it to make aluminum push sticks?

(they look like aluminum chips in the first picture..)


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## Thom2 (Nov 12, 2004)

gregW said:


> that's pretty cool Thom...thanks for the info.
> 
> are you using it to make aluminum push sticks?
> 
> (they look like aluminum chips in the first picture..)


If you're familiar with Lee Styron (www.leestyron.com), I spent a year or two making the push sticks for him that were sold with his Shark Guards. I've since given up that gig, but the vacuum jig was AWESOME for that work.

Here's some other pics if you're interested:

http://bt3gallery.fhauto.com/view_album.php?set_albumName=SharkFeeders

and here's a good shot of why my shop used to be nicknamed "Tinseltown"


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## jigmaker (Jul 17, 2007)

What size air compressor are you using, i am thinking of using this to draw a vacuum on a vacuum veneering bag.


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## AxlMyk (Jun 13, 2006)

Someone on E-bay has several of these.
http://cgi.ebay.com/Gast-Vacuum-Pum...yZ109622QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


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## kp91 (Sep 10, 2004)

Thom,

Love your setup, especially the price! Thanks for sharing the ingenuity. I might just have to make a trip to HF to play around with this one!


Jigmaker,

the spec sheet from HF says 4.2 CFM, so most any shop air compressor should work. Tank size shouldn't be too important, since you'll need a valve to shut off the bag after you've pulled the vacuum (assuming no leaks).


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## jigmaker (Jul 17, 2007)

kp91

I am working on a vacuum controlled switch to operate the compressor so it will maintain a constant vac., i will post the results when i get it working. My compressor will produce 4.2 cfm at 40 psi.


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## Thom2 (Nov 12, 2004)

I am running a 60g compressor, but it wouldn't need to be that big for this application. There is a big difference in air demands between vacuum clamping and veneering too. 

One thing to remember with clamping, the bigger the template, the less vacuum you actually need, the rule of thumb is that 1psi = 2" of vacuum. With this in mind, here's some examples of the force applied to a template.

12"x12" (144") panel @ 2" of vacuum = 144 lbs
12"x12" (144") panel @ 10" of vacuum = 720 lbs
12"x12" (144") panel @ 20" of vacuum = 1440 lbs

With a venturi, the air consumption is related to the amount of vacuum you're trying to pull. If you're trying to pull a full 20" vacuum all day long, you're gonna work the dickens out of your compressor. If you're templates are big enough tho, you can cut back the vacuum significantly and still have plenty of holding force.





jigmaker said:


> kp91
> 
> I am working on a vacuum controlled switch to operate the compressor so it will maintain a constant vac., i will post the results when i get it working. My compressor will produce 4.2 cfm at 40 psi.


Turning the compressor on and off with a vacuum switch is not going to work for the venturi setup. I highly suggest you look at air solenoids if you're going to use a venturi vacuum pump. You don't need to operate the compressor, you need to control the air flow to the venturi. The compressor motor needs to be able to control tank pressure and can only do that if it is controlled by the pressure switch on the tank.


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## jigmaker (Jul 17, 2007)

kp91

Thanks for that info i guess i better do a little more research before i get into this very far, i have built a vac. pump using a refrig. compressor and it works, but i thought i would use a system using the venturi ,that way i could be using two bags at the same time. Not only that but i enjoy playing around with this kind of stuff, it keeps me off the streets, as my wife would say.


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## Thom2 (Nov 12, 2004)

jigmaker said:


> i have built a vac. pump using a refrig. compressor and it works


The original poster of this thread was asking for tips and advice on using a refrigerator compressor, perhaps you could offer him some assistance????


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## kp91 (Sep 10, 2004)

PLEASE-- if using a refrigeration compressor, make sure the unit was properly evacuated of freon- don't just vent it to the atmosphere. (up to a $10000 fine if caught)


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## Joe Lyddon (Sep 11, 2004)

Thom2 said:


> I can't say much about using a refrigerator compressor, but I'll show you my rig anyway.
> 
> 
> ... this vacuum rig I built cost me $10 .... yes ... $10 ..... I know you can't believe it, I know you've been shopping and gasping at the prices of these rigs .... but I'm telling you ...... T-E-N D-O-L-L-A-R-S
> ...



WOW! Thom, I think you've hit a few nerves here!!

I'd sure like to see a new thread on the subject where you describe your system in more detail, close ups, bags used / made, how to use system, etc.

This is the first time I've seen this possible for such a reasonable price!

Thank you very much!


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## duckarrowtypes (Aug 28, 2007)

I'm digging up this old post so that I can ask a followup question. I'm considering getting one of these v-clamp venturi vacuum hold-down puck kajiggers but I don't have a source of compressed air.

I'm wondering just how much this little bugger will require from a tank. If I just got one of the little 1 gallon tanks would the compressor be kicking on constantly? I'd prefer not because of the noise...

What do you say oh masters of woodwork?


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## AxlMyk (Jun 13, 2006)

At 4.2 cfm usage, you won't have much time before a 1 gallon tank runs out of air. You would have better luck with a vacuum pump connected to the clamp system.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=98074


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## Mike (Nov 22, 2004)

It strikes me that when you are using a vacuum bag system you could get away with a Foodsaver or Seal-a-meal to draw the bag down. It would not be fast but should do the job for cheap. Has anybody tried this?


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## Errol (Dec 13, 2006)

A brief note to Duckarrow.
The V-Clamp kajiggers do work well, but if you want to keep your compressor cycling on and off frequently set the supply to 60 psi. Holding power will be 9% down, air consumption will be 25% down
Errol


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## tribalwind (Oct 3, 2008)

looks like the photos are gone from thoms initial reply, bummer' 
i'd like to set one up, 

i do have an old fridge compressor that was given to me while ago. no idea on using it, was full of oil (empty now). if i can just use a small harbor freight vac i'd rather go that route if fridge is complex or needs oil changing etc.


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## jigmaker (Jul 17, 2007)

I tried using a frig compressor and had a problem with heating up and activating the thermal protector switch, i couldn't figure out how to override the switch. it would pump up a good vacuum but after a while it would heat up and then it wouldn't start so i was loosing the vacuum. I give up on it and now i am trying to get up enough funds to purchase a commercial pump and bag system. Jim


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## jjciesla (Oct 20, 2007)

Check out;
http://www.roarockit.com/
It's a skate board site that sells vacuum kits with a hand pump, for small jobs.

Here's some other sites for vacuum info.
http://composite.about.com/od/aboutcompositesplastics/l/aa000109.htm
http://www.bertram31.com/proj/tips/vaccuum.htm


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