Polycold Cryotiger -203c on ebay for under $200

[Charles Wirth]

A small Cryo compressor, a good started project for someone who wants to venture down this path. Low wattage, low price but should be fine to learn.

Or... Suck the gas out and use in a cascade. Several on ebay at this price. Polycold gas blend as awesome and very expensive.

http://www.ebay.com/itm/IGC-Polycold-Cryotiger-Industrial-Cryogenics-Cooling-Refrigeration-Compressor-/131355798548?pt=LH_DefaultDomain_0&hash=item1e956a6c14

PDF:

http://instrumentation.obs.carnegiescience.edu/ccd/imacs/docs/ICG_Brochure.pdf

[n00b 0f l337]

Sadly these aren't the mythical unicorns they look like. The box is just a compressor condenser oil separator. The hoses and cold head provide all the heat exchange and capillary lines. And while the gas charge is present, the cost doesn't support it... sadly I know this because I have one on the shelf.

On the other hand. If someone grabs this I will help you find a cold end and hoses if possible, or would be happy to help build one.

[Charles Wirth]

I am a bit more adventurous, I would suck the gas out as the cheapest polycold charge will set you back $700

I have a larger CTI with helium compressor.

[n00b 0f l337]

The charges are certainly expensive!
I think we can make that mix for far less though. And even less still if we look through Mytek work with hydrocarbons.

[Charles Wirth]

You and I can do our own blends for much cheaper, this was a less expensive option for parts and gas.

It is a full condensing unit with brazed plate heat exchanger built into an autocascade single compressor with custom gas mix.

I think Cryotiger is PT50 ~ $650 per charge

[Crabby]

So basically one could build a line set for this and have a charged autocascade? Assuming it is fully charged.

[n00b 0f l337]

You'd need a specialized vacuum sealed evaporator system. And you'd get a -200C at 10watts.