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[rubyredrose]

I am am making a steampunk styled gas gun, with a fuel tank backpack, see here. My questions are about materials.

I am wanting the central cylinder to be a clear plastic filled with colored liquid of some sort. What can I use for a cheap, easily available clear plastic tube or cylindrical container about 10-12 inches in diameter & 10-18 inches tall (or easily cut-able) for the base of the "fuel tank"? It needs to be rigid enough that I can wear it as a backpack, but something I can drill holes into for supports.

Secondly, what liquid should I use for the "fuel"? With plain water I am concerned about mildew (ideally this would be permanently sealed) and adding soap or bleach would make it sudsy. The liquid would need to be able to be colored, so...food coloring? Ink? What would work best without dying the plastic?

Thanks for any sugestions! n_n

[Kitsoru]

2 liter soda bottle? I've also found 1 liter bottles. Science supply stores often have these kinds of things, so I'd look there.

As for liquids, if you're bringing this into a con I'd make sure it's something they'd be okay with you bringing in... But I'd think food dye would work fine. You could test different things to see what works well with the plastic. Is there a particular color you'd prefer?

[FullMetalSam]

Wow... that's one hard question.
For the clear plastic tube - in the dimension you're looking for - I really don't know where you'd be able to find it - but it's going to cost you a bunch of money. You should be expecting the price tag to be very high.

Have you considered heat forming a sheet of plexiglass into a tube of your desired dimension. OK, it's way more work than just buying the tube - but it's going to be way cheaper. You could even use an opaque tube as a support (trashcan, tupperware (which I've seen with big diameter - though not 18" long), etc.).

As for the liquid... as you said, I would stay away from water... but you should consider Shampoo. You're not going to be able to color it, but there are shampoos of various colors and some really cheap ones (because you're going to need a lot of liquid).

Good Luck!

[astillar]

Ditto to Sam, that's an uncommon size for a clear cylinder. A cylinder with those dimensions, even if only half full, would add up to about 3 gallons, which would make for a heavy backpack. As for keeping the liquid clean and clear, an alcohol additive (rubbing or drinking kind) should keep the microbes at bay.

[rubyredrose]

Thanks very much everyone for the suggestions! n_n Astillar, your point about liquid weight is a good one, so I've scaled down the main tank size. In case it's helpful to anyone else in the future, I ended up selecting a food container as my main tank and will be using water bottles as secondary tanks.

FullMetalSam, if I'd kept the original scale of the backpack, I'd've gone and shaped the plexiglass...that was what I was originally thinking I'd have to do. However, upon reflection, I've decided to make the backpack drainable, and tone down the size, in the interests of sparing my poor back.

[jc3394]

Love the concept drawing and can't wait to see the finished product.

If you're looking to fill it with a liquid, you could try what come magic tricks use: double containers. Using your "container store ref pic" you could stick the front smaller container inside the larger one and just fill the space between the two containers to give the illusion that it's full to keep down the weight.

Let us know the progress and finished product!