Ultra low-temperature cascade refrigeration system repair

I bought a -100*C refrigerated cold trap from a surplus sale, which was not operational.  In this video, I describe how the unit works after recharging its second stage with R1150 (ethylene) refrigerant.

Savant RVT4104 - (manual) http://phoenix.tuwien.ac.at/chemistry/Gebrauchsanweisungen/SAVANT%20Vapor%20Trap.pdf

Vote for future video topics on Applied Science

Upvote here:  http://www.reddit.com/r/AppliedScienceChannel

How to electropolish aluminum

I show a basic electropolishing technique that requires no special equipment and has proven to work well on aluminum (aluminium).