A bit out my depth... but I'm not sure why use alcohol and dry ice? Is the goal to keep it warmer than -50C to avoid damaging the board? If not why not fill your tank full of liquid nitrogen? it seems like it would be a lot safer.
I can't use straight LN2.I'm pretty sure if you just poured LN2 on a running motherboard it would immediatly die.Thermal shock is no joke.
By using Isopropanol and dry ice , I can bring the temp down reasonably slowly, thus minimizing the effects of thermal shock.
Secondly , the physical requirements of a tank/recirc system designed to handle LN2 is a lot more mechanically demanding.And expensive.
I'm really not sure LN2 would be any safer.While using flammable solvents seems really dangerous , in reality , flammable solvents are used every day in industrial applications.As long as the correct protocols are followed , it's really no big deal.
Before I give you a sneek peek , let me explain why updates are slow on this sucker.A good portion of the materials required for this are very difficult to source.I Just found 'proper' borosilicate glass :
I am waiting on quotes.It might be $$ so we'll see.
I have also found the 'exteriors' for my vacuum jacket lines.
here's yer pic :
I have every part (computer wise) except the video card.
I am working on the 'inners' for the VJ lines.
Once I decide on proper inners (and have pipe sizes etc),I can start worrying about the pump in earnest.
This is the hard part.
Just try and spec out a 'cheap' pump for alchohol at -80c.No such thing exists.heh...I'll be using the soviet method for building my own pump , I think....The 'blood and thunder' way assures results. I should have some prelim pump building pics soon.