Does anyone know what is the smallest size possible? I've been looking around and all I found were this fat non refillable tanks at walmart.. I just want something I can carry around inside a briefcase or book bag, I know it sounds crazy but the only reason why I want this is because I think I have seen it somewhere before...i'm not crazy.

I need it for a magic trick I do where I get a kid to inflate a balloon by mouth or with a pump if he cant by mouth, and then I tie a string to it and draw eyes and tell the audience I'm going to hypnotize it and make it think its a helium balloon, at the end I make it float and give it to the kid as a souvenir . does anyone do this? or anything like it? I know its published somewhere, I made this my own way but the effect has been done before.

Any help would be appreciated.

Try a diving or scuba outlet or ebay for a "spare air" tank, or emergency tank. I'm not sure how big they are but this is probably your best bet!

good luck,

best wishes
Danny

Try http://www.spareair.com and check out the 170 Model which is under 9" high.

You may need to check if you can fill it with helium.

I'm not 100% sure on this, but I would think that you could use a small CO2 tank like the refillable sort they use for paintball. Try to find a dis-reputable gas distribution hub that will fill it without it being certified for the purpose.

Only kidding on that last bit. Seriously though, I know that with the CO2 tanks they have to be inspected and licensed before you can fill them.

The first thing you need to do is find a source for helium once you have that they can direct you as to where to find a tank. in fact they probably sell them. or for a small deposit they give you one. when you return it you get your deposit back, or roll your deposit over to the next bottle. I am sure helium tanks are like any-other tanks that hold gas.. they are only good for so long then you cant fill them anymore so renting a tank might be better then buying one.

Thanks for all the good info, I know of a good helium supply, I'm gonna contact them and see what they have..

I once saw a hot air balloon pilot use a small tank like you described to inflate a balloon to test air currents before lift-off.

Maybe hot air balloon supply places might have them.