Subject:
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Re: Inexpensive air tank found at WalMart!
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 15 Feb 2000 01:01:58 GMT
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Viewed:
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1024 times
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I got frustrated with the low capacity of the little blue Lego air tanks soon
after I started playing with pneumatics, so I came up with my own design for a
home-made air tank, as well.
My air tank is made from a regular plastic soda bottle, a small piece of
stiff lego tube (I took mine from one of the little <$10 technic sets) and some
hot glue. I later added the valve stem from an old bicycle inner-tube so I
could fill my tank with a small bike pump.
All you have to do is drill a hole (or two or three) in the top of the cap of
the soda bottle, just big enough for the little tubes to fit snugly (I think
it's 1/8"). The plastic is soft, so it's actually easiest to hold the drill
bit in a pin vice and just twist it through by hand. Pin vices aren't that
common, so I guess you could use a pair of vice-grips in a pinch. I think I
used one of my larger x-acto handles which happens to have a 1/8" hole in the
blade-chuck. Then push little (~3/4") pieces of tube into the holes so that
about 1/4" is inside. Use a generous helping of hot glue to hold the tubies in
place. You can put glue both inside and out, but be careful not to obstruct
either the air passages or the bottle cap threads. You can quickly screw the
cap on the bottle and then take if off before the glue cools to make sure the
threads are clear.
That's all there is to it. You can use any size soda bottle, 20 oz for a
small machine, 2L for a big one. It's fairly easy to pump up a 20 oz. bottle
with Lego hand pumps, or probably with a lego compressor. For a 2L bottle you
can cut a larger hole in the cap and fit in a valve stem from an inner tube.
Then you can use a bicycle pump to charge your air tank.
Please be careful if you use a bike pump though, you could easily build up
enough pressure to blow up the bottle if you don't destroy you Lego first.
So try to use some sort of pneumatic safety valve. Definitely don't use a
glass bottle. And leave the plastic label on your soda bottle because it's
actually designed to strengthen the bottle. (Sorry about all the warnings, I
worked for a while in a gas turbine lab and learned all about what happens when
pressure vessels rupture).
I'll try to take some pictures of my setup and put them up on my nonexistant
website. I'll post the URL when I do.
Phil
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Message has 1 Reply:
 | | Re: Inexpensive air tank found at WalMart!
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| (...) Ok, take a look at: (URL) cap of my pressure tank, with 3 air-ports and 1 filler valve. Two ports are connected by a short tube to seal them off temporarily) and (URL) cap attached to a 2L bottle) (25 years ago, 15-Feb-00, to lugnet.robotics)
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Message is in Reply To:
| | Inexpensive air tank found at WalMart!
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| After receiving my pneumatic parts on Saturday (Thanks Steve!) it didn't take long to discover that an air tank isn't a "nice-ssity" it is a necessity! So I thought a baby food jar fitted with a barbed line connector would make a great little air (...) (25 years ago, 13-Feb-00, to lugnet.robotics)
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