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How to compress air into a hollow solid without a valve? Answered


Really need some help with this one, have searched everywhere but cant seem to figure it out. I know there is probably a very easy solution i'm missing so please help.

Basically I want to compress CO2 at around 80 psi into a hollow metal. I have drilled a micro hole and created an opening (about 2mm radius) into the metal. My problem is after I compress the CO2 in there how do I remove the compressor nozzle and seal the hole without the CO2 escaping. 

The metal is small and there is no place for a valve. Is there such a thing as a self sealing removable valve? Or could I use a valve  with two openings and pump liquid metal (that would than solidify) and seal the hole so I can remove the compressor?



with the correct equipment, you could seal the tube by crimping. With the right tube and some preparation, you could seal it with a soldered seal as well.

Make the feed tube slightly longer than necessary. fill the feed end in ~1-2 inches with solder. Drill through the solder with a bit smaller than the tubing's inside diameter. Use this end to fill the ampule.

Once you've achieved your fill pressure, crimp the tube across the soldered area.

Cut off the crimped tube from the feed hose. with the crimping vice, pliers/etc in place and under pressure at the ampule end, heat the cut end until solder just flows. remove heat and allow to cool.

That *might work, idk...

Why do you want to do this?
(compress CO2 at around 80 psi into a hollow metal)



6 years ago

The only thing that comes to mind is to place a small rubber or soft silicone ball inside the tube. When the tube is pressurized, position it over the inlet and the remove the hose. The internal pressure should force the ball into the hole sealing the opening.


Not too soft, though, or it could end up deforming enough to fit into the hole and come out like a bullet.

It would make a wicked pea shooter, eh. :)

...pointed right as you...

How thick's the metal ?


Assuming you don't need to get the Co2 out again by the sound of it - why not generate it inside the sealed tube - CO2 is a simple gas to produce - vinegar and baking powder will do the job, it will generate it's own pressure although you may need to experiment on ammounts required.

You can put the liquid in a glass vial and weld the tube shut the shake to break the vial.

Otherwise a simple flap valve inside the tube will seal the hole.

Maybe you could get some dry ice and place your little piece of metal on it so the metal gets very cold. While it is getting cold, cut a bit of the dry ice off, and place it in the little hole when the metal is cold enough. Then, plug the hole and get your metal away from the dry ice. When your metal thingy warms up, the dry ice inside will melt into compressed gas, sealed inside.