Where?

[scrumpyjack]

I have chosen to adopt a realistic submarine ballast system ie a ballast tank that is blown to rid the tank of its ballast water, so..............
Where can I source a mini air tank that can be charged by a mini compressor please. I have done the ebay search and found a 'Leggo' tank the mind boggles!!
AND question two what about a mini compressor? I thought about a 12volt tyre compressor the ones you can find in Halfords that plug into a fag lighter.
Fred the dopey question provider!!

[ramius-ii]

Hi! http://www.subcommittee.com/forum/icon_biggrin.gif
What makes it

Hi!
What makes it difficult to give a accurate answer is not know what scale you are working with therefore there are dozens of choices of various sizes. If you are limited by size then you may consider using the compressor from an "Airsoft" gun. As for tanks, you may wish to consider just making them yourself from copper, or brass, or thick wall aluminium tubing. Whatever your choice you can find the PSI rating and it may be prudent to choose a tubing that is rated for twice the operating pressure. The key is all these decisions is what pressure (PSI) do you plan to work with? Any compressor must have a source of air to compress so this is another consideration as to where will the air come from to replace the air used to "blow ballast"? The 12 volt car tire type compressors are capable of 250 PSI so you would need to limit or regulate the maximum pressure. I become very nervous with 50 PSI. I hope this answer provides some food for thought and additional design considerations.

Best, Ed

[Guest]

In a nutshell, if you're

In a nutshell, if you're going this route, then you will need to make a lot of bits and bobs yourself, especially for the size of model you are building.

The tyre inflater compressors work okay, but they are manufactured to a price, and the quality isn't great. A converted IC engine is a much better proposition, or you could always look at the range of piston pumps manufactured by Thomas- be prepared for a hefty blow to the wallet.

I would advise against using brass tubing for a pressure vessel- not the most stable of metals. Stainless steel or copper is better.

[Wheelerdealer]

The VW/Audi tyre compressors are

The VW/Audi tyre compressors are excellent and can be found on eBay. They go up to 85psi only (which is plenty for your purpose). Robart air tanks may fit the bill, they are rated to 150 psi. Airbrush propellant is stored at 70 Psi, so an empty can of one those will work.

[Guest]

The VW/Audi compressors are bit

The VW/Audi compressors are bit on the large side, although much better quality than the 'el cheapo' tyre compressors from other sources. For a start they're well balanced.

They're made by a company called Valeo, and the German modellers like to use a pair of them for their big 'pressluft' boats, although one would be more than sufficient for a smaller boat as they shift a lot of air.

If you were to replace the standard motor with something a bit smaller, and lay it on it's side, then you could probably squeeze it in.

I've no experience of the Robart cylinders, but they look like standard aerosol canisters (probably aluminium). For a compressed air cylinder, which will be sucking in humid air, I would like a drain plug to enable moisture in the tank to be drained out.

I would think these cylinders are likely to be a tad too thin to enable the fitting of a plug, but even assuming there was enough meat on them, any alteration of the cylinder like this will lower the pressure strength of the cylinder. Definitely an area to over-engineer.