Forbidden Donut

Wrap it in enough duct tape...

While generally a good idea, there's nothing to wrap. I'm trying to glue a fucking rubber(ized) gasket to the inside of a cryogenic metal box...

Lowest temperature commercial glue I've found can handle -75C, which doesn't quiiiite cut it.



I will add:

Fuck Gravity.

What's the margin for error here? If you try one and it doesn't work can you just try another one or is this a one shot kind of thing.

The only solution I could offer would be trying a product designed for use in extreme temperatures, such as JB-Weld. I realize that cold and hot are two different things, but its about all I can offer.

Much Obliged.

I'm mostly pulling together a list. We're going to conduct an experiment when we have some spare time and I want as many freaking samples as possible.

I wouldn't be surprised if there weren't any adhesives that were actually designed to handle temps that are over halfway to absolute zero... But it'd be nice. As it stands, our solutions all entail poking holes and bolting this crap on, which is shitty and doesn't form as good a seal.

I'll go ahead and tack that on *The List*

Hmm Weird. I made another reply earlier this morning and it didn't stick (stick, get it?, bahahaha).

Anyway, one more try. My other suggestion was to use magnets to hold the gasket in place. You don't lose any integrity in the rubber from drilling in it, its re-positionable, and magnets only increase in strength as they get colder. Could be fairly inexpensive at any hobby store depending on the thickness of the gasket and the surface you are attaching the gasket to.

You might be a fucking genius.

Edit: I'd like to add

Is the cryo box made of stainless steel? If so forget the magnets. I work with cryo liquids occasionally (oxygen, argon, nitrogen etc.). I don't know of any adhesives off the top of my head. Will look into it.


found this stuff.

Armstrong A-12 epoxy is used in many cryogenic applications including liquid helium dewars.

The box is in fact SS. Annoying, but I came up with a couple mounting ideas.

Meanwhile, I'll most definitely look into that.

/I really didn't expect much of anything to come out of fd.
//I guess we're all growed up and shizz.

Why the cold box? Going to put your PC into it and do some serious overclocking?

I also notice that the gasket is on the inside of the box. This tells me you are going to use a pressure vessel type door (the more pressure the better the seal). Don't forget to install an emergency pressure relief valve that will bleed off at less than the max pressure capability of the box. Also you will need a manual valve to bleed off pressure so the door can be opened at the end of your project.

I must admit you have piqued my curiosity. Just what kind of shenanigans are you guys up to? Also how will the door be held in place? There is a good possibility that all you need to do is place the gasket on the door WITHOUT adhesive and then pick it up into place and make the seal.

Also I noticed that you said "rubberized gasket". That may not hold up too well in a cryo application. We never use rubberized type gaskets. They do not hold up well when the temp drops. They tend to become brittle. Teflon products should work well. Gore makes some good stuff. A bit expensive though. There are other gasket materials that may be better suited. I would need more info on what you are doing to answer though. I also on occasion have access to some "free" gasket material. One of our clients is very easy-going and will probably let us have some gasket material at no cost, as long as it is not a large amount.

Well, let's see what I'm allowed to tell people...

I happen to work for Gore. We're also using Gore Skyflex Aircraft Sealant in this application. /smile.gif" style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" /> It is in fact, awesome. And for us, it's free /biggrin.gif" style="vertical-align:middle" emoid=":D" border="0" alt="biggrin.gif" />

The gasket material itself is rated for temperatures below -170C, which is beyond our intended range.

The Application:
This box is actually part of a much bigger apparatus called a thermal shock chamber. There are two "boxes" with a hole between them. A pneumatic elevator carrying a basket (and whatever we put in the basket) can travel between the top box and the bottom box. One box is kept very hot, and the other very cold. We don't want them to share those characteristics with one another as that can become expensive. Like leaving a window open with the AC on, only the AC is trying to keep it at -160C and the outside temperature is more like boiling water.

A gasket lines the top edge and bottom edge of the hole, and a sealing plate travels with the rest of the elevator to seal from the top when the elevator is down, and from the bottom when it is up.

With me?

The gaskets lining the top edge of the hole are fine. They have gravity on their side as well as there being a multitude of heat resistant adhesives.

The gaskets lining the bottom edge stay intact just wonderfully, but they eventually sag and droop, and then the sealing plate can fold them over when it goes up the next time and *that* snaps the shit out of them.

Curiosity sated?



The pneumatic lift is ... violent. We have that aircraft sealant sticking pretty well to it at the moment, but it'll need to be replaced quarterly, at least. We added that crap because the monkeys that use this chamber don't let it dry out before firing it up again. Make a box cold, open it to humid air, and cool it down again and you get... lots of ice. Since the aircraft sealant is made with our special Gore crap, the water beads off and ensures that we don't freeze the stainless steel elevator body to the porous rubberized gasket.

It helps, but with temperatures this extreme we actually need a seal with ratings as high as the one we're using anyway.

The temperature bleed or "droop" was much too high with just the AS, which pissed me right the hell off.

Explained it very nicely thank you. An airlock or in this case temperature lock. Maybe the A 12 will do the trick. As to actually working for Gore, you guys make some good stuff.

Next time you guys may want to look into using a rotating airlock type system. Much less violent.

:Big fat winking gif:

Think:
No moving parts, save a ventilation fan or two.

That stuff looks pretty awesome.

I can't seem to dig up a data sheet that *proves* it can do it. All I see is a tensile strength of 2500 lbs @ -60. I'm plenty convinced, lol.

Worth a fucking shot, eh.

I hope it works. I know how annoying it is to replace gaskets/valves due to design issues. There are several that I have to work on about twice a year.

Yeah man. It's bullshit.

We were in a position before adding that Gore material to it in which we had to replace that bitch once a month.