What size dewar would you recommend?

Josh Rider

Josh Rider

Stuff maker
Joined
Sep 2, 2014
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After 3 years I finally decided to buy a proper kiln.

For now I will be doing carbon steels and venturing into steels that can benefit from sub-zero.

I’ll be on the lookout though for a dewar, so what size should I look for?
The widest blade I can see myself doing is a chef’s knife occasionally.

Thanks for any recommendations.
 
You would be looking for a "Wide Mouth" Dewar most of which will be 20 Liter and above. Be sure to ask how wide so you can easily insert a 2" wide blade and the 20 is deep enough for a Large Chef Knife.
 
Mine takes just over 2" blades and I personally would not go larger. The larger you go the faster you loose LN just in storage. Dewars are rated in loss at L/day. My dewar is very efficient and has a rating of .09L/day. If your doing lots of blades quite often then the loss is not as big of a deal becaus your going to be filling your dewar every month or so. But even with me doing the heating business on the side I only fill mine every 3-4 months or so and some times even longer.
 
I got a 10L with a 1.9" mouth. For me that will do 95% of what i do that gets cryo. And seems to be the most bang for buck in dewars.
 
I wanna say 12" depending on your liquid level. I'll measure when I get it filled tomorrow.
 
From reading a few papers thy say then entire chamber is -300 or less between the liquid level and the bottom of the foam stopper.
 
Interesting, I wouldn't have thought that but it makes sense when I think about it. Ice in the freezer isn't any colder than the air around it either.
 
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