Designing a ln2 pot Need input

I am working on a design for a liquid nitrogen cooling pot and need some input. So far the design will hav 3.8 pounds ok copper, and 1 pound of aluminum in the base. What I need to know is how large can the base be. Right now my base is 3 inches by 3 inches, would this be too large?

Note: OP was with a smartphone, I didn't have internet on my pc until ~30 min ago... ISP is phail.
I want to make them to sell them, So I want them to fit anything.

I just found intel's datasheets, and I have one from ASrock for the AM3 holes, and AMD's are all mounted the same, right?

If so, I should be good (Thanks )

So, On to design..

I've read what articles about LN2 pots that I could find, and done my own designing and math to come up with what I have. But I'm not designing the pot for my own hardcore use, and I want to get input from those who have much more experience freezing CPU's.


Here are a few things I'd like to ask:



Temperature probe:

What Diameter temperature probe do most people use? Mine is .184 inches, notably larger than most.
If you were to recommend a size to make the most people happy, what would it be?



Mass:

How much is enough?
My Design in progress has 3.8 Pounds of copper, and ~1 LB of aluminum in the lower part of the base (I didn't count the walls in my calculations, I figure they don't matter as much)

I can add more copper mass (with little impact to surface area) but It would make it more expensive in material.

Should I aim for more mass, or... what is the preference?

(I haven't done any LN2 benching yet. Only dice. Seeing as my HW store doesn't carry LN2 (I could put in a PO with A&L gasses, But I dont have a dewar, or the money for one anyway))



Surface Area:

Does Too much hurt? Or should I make it as much as possible?

I'll provide exact figures for my design later.



Mounting:

I Intend to make universal mounting brackets (using the prints mentioned above), one goes on the pot and and goes underneth. Same as my dry ice pot.

Does anyone think that would be inconvenient for whatever reason?

(Those hex pieces slide on, and the setscrew in the side lets you lock them, then you can use them to screw the rods into the backplate. I personally really liked the setup, I could feel and torque each of the 4 corners just the way i wanted)




Volume Capacity:

How much LN2 should a good pot hold? ATM the design holds ~2.5 cups (leaving 2.5 inches of tube unfilled) but all I have to do is increase the length of my aluminum tube to increase that.



Attachment of the tube:

At the moment the tube that goes on top Is interference-fit, which means anything short of a sledge hammer or hydraulic press couldn't remove it. (Someone told me these come apart when it gets cold, and some pots have failed because of it. I see how a poorly done Press-fit would come apart at LN2 temps. But not a strong interference fit, with equal cross-sections in the two parts.)

Would a permanent top be an issue for some reason?
If it might be, I could put in a tight thread, but it would take a lot longer to make the pot.



Cross-Section:

The Shortest cross-section between the LN2 and the processor would be .625" in my current design Does this sound acceptable, too thin, or too thick?



Shape:

Does this look good

I am going to be using a square base again (works well for mounting, both at the mobo and in my machine). The tube isn't going to be so thick, though. (Bigger OD, thinner walls, inside NOT done with a cheap ass chinese boring bar that flexes .5 over 4 inches!)


Those aren't scratches, it's frost! If I make pots to sell they are going to be very well finished. Scratches, chip indents, use of mechanical abrasives... ALL inexcusable!


If anyone feels like commenting on these aspects of the design, or pointing me to resources, I'd much appreciate it.

I can use it to make it as tight as I want. (short of stripping out threads)

I'll see about other mounting mechanisms though, it would probably be better to use something people are familiar with. (And that doesn't require a hex-wrench)

no no, you slide them on and then tighten the setscrew, no pressure required

after all 4 are on and locked, they act like handles to screw the rod into the backplate, torquing it to your feel.

This is on my todo list, I just dont have the time ATM to look through all of the specs to make universal mounting hardware.

Once I have the time, I'm going to make ~ 5-10 of these

I'm going to use 2.75 Diameter 5052 Aluminum

The Aluminum has 60-70% conductivity of pure copper, But pure copper is so hard to find, What I've seen is alloys being used, which means The aluminum will have ~80% or better of the thermal conductivity of a typical copper pot. without the oxidation issues.

Approx 1/3 The Mass of a copper, good for bottoming out temps with dice, there will be enough mass to prevent temperature swings. (You are going to keep this thing full with dice, right?) And It won't take long to bottom out.

The tube on top will hold about 2.5 cups of volume, way more than you need for dice. (You will need to refill every 8 minutes with this, in my experience.)


The "Mounting gear" will be two plates. I will include a piece of insulation to be used between the plate and the mobo.
(I could also make a motherboard mounting plate like I did with my original pot, but thats a lot more material.)


EDIT:
I got a PM saying the post was removed for advertising without being an official vendor, but I looked here and this post isn't removed, So I've removed the portion where I was thinking out loud about making kits.
Edited by General_Kerr - 3/1/12 at 11:25pm