Homemade liquid nitrogen generator using JT throttle and regenerative cooling

Hello all. I found this site and thought I could post what I have been up to and ask for advice from those who may have worked on a similar project. I have been building a homemade LN2 generator. It is not a cryocooler. I don't use premade cooling devices. Mine is built from the bottom up like Linde's original device.

I plan on making a better video, but I finally collected my first batch of liquid air. Using pure N2 will be soon.
http://www.youtube.com/watch?v=4Go9b2eMiHQ

I am just wondering if anyone has done this before at home? I am still trying to improve my regenerative cooling coils. Also, does anyone have experience with the joule thomson throttle? Specifically, is there an optimum design for expanding the compressed gas?

Thanks.

I have wondered but never tried, I knew that I could condense other gases from the air but never tried to capture.

I am one of the few with a working helium compressor and a cold head that needs to be reworked into something useful.

Where did you get your helium cold head from and how much was it? Originally, I thought of doing it that way, but I wanted to do it without using pre-made technology (other than the compressor).

The few I saw on Ebay were over $1000.

Ebay!

I purchased a CVI compressor for $138 delivered about 8 years ago and it came with a cold head. I planned to rework the cold head into a LN2 pot but I never was not able to get the aluminum fittings installed correctly with good seals from stainless quick releases. I purchased a few extra LHe hoses under charge and one day I may attempt again.

http://fugger.ipage.com/cvi.png