DIY Vacuum Fixtures

[Boyan Silyavski]

PS. I will use the compressor directly. It will suck from where the filter goes. Will disconnect the normal pressure regulator. Still not sure if i will need a vacuum deposit or not. Will try both ways. I read on the Zone, so many people are using setup like that and report no compressor heating even after 8h constantly working. You know its easier to suck than to compress

[EddyCurrent]

Also there were these threads about the subject;
http://www.mycncuk.com/threads/6710-...a-vacuum-table
http://www.mycncuk.com/threads/7824-...-cutouts-edges

[Boyan Silyavski]

Ok, just tried running the compressor for half an hour and it did not heat at all. Unscrewed the outlet quick connector and screwed a connector where the compressor sucks air.Then taped the inlet . 30 min was ok. Just was going to report here and it turned off. Waited 5 min tuned it on and it run again. It was almost cold to the touch but obviously something heated. But before i rip it apart and search for a termistor or something , i would like to see if it will work for the fixture or not.

Yeah, i read all the threads here and at the zone. However my conclusion is that i have better have fixture for each job or for the universal table, to have a mat for each job. That covers all unused holes and produces enough friction at the borders and may be inside the job too if needed. Some plain cheap mat will be perfect. Later will go on shopping.

[mitchejc]

Silyavski, its great news to know that using the compressor inlet works well. Would it not make sense to use an old 9kg or 12kg LPG gas cylinder as a reservoir + a simple one way valve then you don't have to run the compressor all the time?

[JAZZCNC]

Be careful with compressor tanks they are designed for positive pressure not negative and they DO implode under high vacuum esp if they are old rusted and not vented correctly.

I'm not scare mongering here it really does happen. My son builds and tests tankers and you'll be amazed at how destructive Vacuum can be on what seem like strong tanks. Watch the Video.!
The Lad in the Green jumper connecting the pipes at 3:19 is my Son he was also the one who crushed the tank hiding behind the tanker while filming and venting the tank . This was an old tank with it's internal baffels cut out to help crush (Your compessor also doesn't have these braces or baffels.) and you'll be amazed how little Vac pressure was needed to flatten that thing.!! . . . . Don't under estimate Vac pressure it's a Killer.!


If your planning on using the compressor has Vac tank then suggest you weld exterior rings as braces to strengthen. Like this.

EdIt: Oh by the way those Numpty's weren't acting either they really thought they'd crushed the tank. . .Lol (Serieously)

[mekanik]

Any tank that will withstand 14.7PSI positive pressure(@ sea level) (29.4 PSI absolute)will withstand a vacuum attainable by any compressor you CNC chaps will be using.
I was going to buy a vacuum device for changing my engine oil but they were a bit pricy for a plastic tank and a bit of a hand pump so i modified(or should i say hacked) a 5Ltr pressure sprayer that stood up well on a dry run however when i tried using it on the car the hot oil weakened the plastic and it did collapse, the pucker units are obviously made from a different type of plastic and they have internally moulded rings as per a submarine pressure hull. buddy down the road gave me a small butane tank and i will be converting that shortly. all i am trying to say is if you are using a pressure vessel for vacuum storage you should be fine.
Regards
Mike

[JAZZCNC]

all i am trying to say is if you are using a pressure vessel for vacuum storage you should be fine.
Regards
Mike

Yes and No Compressors by there nature are water storage units and rust internally so old pressure vessels can be dangerous when used as Vacuum storage.
So all I'm saying is just be aware the pressure vessel may look strong but is it really.? . . You got Xray eyes.!

[mekanik]

Appreciate what your saying Dean, and i would suggest that a gas cylinder was used as opposed to a second hand compressor tank. The one i have is prestine internally.
Regards
Mike

[JAZZCNC]

Appreciate what your saying Dean, and i would suggest that a gas cylinder was used as opposed to a second hand compressor tank. The one i have is prestine internally.
Regards
Mike

Yep I agree just don't weld it up.! . . Thats another playing with fire thing I've experienced first hand and very scary.! Pocket of gas in metal exploded and just looked like it had been shot with a bullet I shite my self. . .

Boyan I did some playing around with vacuum a while ago and found that the small pipe was ok if your just pulling and maintaining high vacuum but soon as the vac dropped IE drilling just a few holes the Vacuum would drop and part would loosen.

Noticed Larger pipe held longer and allowed more holes before dropping I think due to more volume thru the pipe but it didn't allow the same high vacuum.
So I'd say if your not cutting thru then small pipe for better higher vacuum and if you plan on cutting thru in a few places then larger volume needed.

I'm a fan of Vac pods they can be placed any where and can work around them, esp good for profiling.

[mekanik]

I will be welding a small threaded adaptor to the base to take a valve for the extraction pipe, but i cut the valve out with a 50mm hole saw and it's been sitting around for over a couple of month so should be OK.
The youtube vids i have seen for window and door manufacture seem to use the movable pad system with various stops for alignment.