Instructables

how many psi can a 5 gallon plastic bucket (found in home depot) can take?

so im doing this for a chemistry project. My plan: to create a cannon with buckets and tubes with ping pong ball. I use dry ice and water to compress gas in the bucket and release the air through the valve. i realized that when i puff air into it and conceal it, (3 to 4 times) the bucket starts to deform.

Vyger2 months ago

Instead of plastic buckets you could get concrete pillar forms. These are super heavy duty large cardboard tubes that are made to hold the pressure of being filled with cement. They come in various sizes both diameter across and length. They are also pretty reasonable on price. You should be able to get them at stores like Home Depot or most lumber yards. So, they are made to resist pressure, moisture and abuse. Might be just what you need. Oh, and they don't shatter and send out plastic shrapnel if the break.

http://www.lowes.com/Building-Supplies/Asphalt-Concrete-Cement-Masonry/Concrete-Forming-Tubes/_/N-1z0wp98/pl#!

Found some examples with just a quick search.

Kiteman2 months ago

Hmm, that's quite a loose interpretation of "chemistry" there - no actual chemistry involved at all, just physics.

If you want to make a cannon for chemistry, use explosive mixtures to generate pressure quickly (no valves needed), or mixtures that generate a lot of gas steadily (carbonates + acids produce CO2) that you can restrain and then release through a valve.

For a decent project that would be small enough to carry easily to school without incident, yet impressive enough to make people jump, I would recommend either a hydrogen cannon, or my own world's loudest party popper.

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Having said all that, I would also say not to use a plastic bucket for anything more violent than a vortex cannon. The plastic is soft, and deforms easily (which would break most seals you can make), the corners create a lot of weak spots that could rupture unexpectedly, and the large area of the top would be difficult to seal in a way that is strong enough for your purposes.

Jack A Lopez2 months ago

FYI, the verb "conceal" means "to hide". The verb for closing something with a seal, e.g. an air tight seal, is just "seal".

For example, I'm going to seal this bag of potato chips with a hot wire sealer, and that will prevent air from getting into (or out of) the bag.

Jack A Lopez2 months ago

I don't think a typical 5 gallon bucket will work well as a pressure vessel.

I think the way to go is to basically build the thing out of plumbing fittings, like this instructable,

http://www.instructables.com/id/Baking-Soda-and-Vi...

I noticed in the "related" panel there.

Sort of a central problem when using a solid reactant, like dry ice, is you need a resealable-hole big enough to fit your solid chunks of reactant. I think a 2-inch ball valve, or a 2-inch union, will give you a hole big enough to drop in your dry ice. The pressure vessel itself would be a length of 2-inch pvc, or if you need more volume maybe you could use a bell-shaped adapter to go to like 3 or 4-inch PVC.

If you think you might possibly want to use the parts again in some other project, then I suggest using the threaded style of ball-valve, or union, plus some threaded adapters. If not, the kind you just slip together and glue will be easier to build the first time, but usually impossible to take apart and reuse.

By the way, I am not sure if PVC will hold pressure at really cold temperatures. Dry ice sublimates at like -78 C, at 1 atm. What I fear is the PVC could maybe undergo some kind of ductile-to-brittle transition,

http://en.wikipedia.org/wiki/Ductility#Ductile.E2....

and a brittle pressure vessel is basically a bomb, which is bad. Although it may be the case that you can design the thing so the PVC itself will not ever get colder than water-ice (around 0 C), e.g. if water is placed in the vessel first.

mpilchfamily2 months ago

A bucket isn't going to handle that sort of thing. The lid is not designed to hold any kind of pressure. I suggest you find some pipes with screw on lids that are rated for pressure. They will have pressure ratings marked on the outside. An old 2 leter bottle could do the trick as well.

Look at instructables dealing with potato guns.

Burf2 months ago

Check the label for any ASTM specs that mention the psi rating, though I don't recall ever seeing any. Or, check the bucket's manufacturer's website to see if that information is available.

Generally, paint buckets are not designed to be pressurized vessels and I would not recommend they be used in that manner.

thematthatter2 months ago

I dont think it will be enough to launch a ping pong ball. Now an old fire extinguisher with a good gauge would be better.

thematthatter2 months ago

I dont think it will be enough to launch a ping pong ball. Now an old fire extinguisher with a good gauge would be better.

thematthatter2 months ago

I dont think it will be enough to launch a ping pong ball. Now an old fire extinguisher with a good gauge would be better.