Should I buy this Liquid Nitrogen Dewar?

International Cryogenics liquid nitrogen storage dewar (NEW)
http://www.amazon.com/International-Cryogenics-Nitrogen-Storage-Capacity/dp/B007XYC40A

I hardly post threads on here but I've been feeling pretty ignorant and helpless lately.

I already had another thread up about dewars but it was non-specific. I found one, which I think looks like a real good deal, but I needed to get your guys' opinion on it.

The problem is I have to decide whether I want it by tomorrow afternoon.

It's $722 from Amazon new so I would think paying $315 for a new one would be good, right? I guess his company won it at an auction as part of a larger "lot." It's brand new, they just don't have any use for it.

I'm sure on the exterior dimensions but I wonder how big the inside is... The reason I ask is because I've seen some dewars that have a bunch of interior insulation that makes the inside a lot different(smaller) than the exterior would visually indicate. If it's 23in tall, I should be able to do 15in blade at least, right?

Here at the specs:

international cryogenics liquid nitrogen storage dewar

Capacity 10 liters
Static hold time 62 days
Evaporation rate 0.16 liters/day
Neck tube diameter (ID) 2.25" (57mm)
Outside diameter 11.25" (286mm)
Overall height 23.00" (584mm)
Empty weight 12lbs/5.5kg
Full weight 33lbs/15kg


Here's an Amazon link to the one I'm looking at.

http://www.amazon.com/International-Cryogenics-Nitrogen-Storage-Capacity/dp/B007XYC40A


Sorry for clogging things up on here with multiple threads here gents. I just need to try and figure this out by tonight. I'd greatly appreciate the help, as always. Cheers! I looked on their website and they don't list the internal height of their dewars. Kind of frustrating.

I found a cutaway illustration of their dewar's internals(see below). It looks like the insulation on the bottom takes up about 1/6th of the height. With an external height of 23 inches I think I'll still have enough room for 15"-16" knives. What do you guys think?

Are dewars able to be filled up into the neck? I know that they probably hold the LN longer if the cap is all the way on but if I need to cryo a longer knife, and was limited by the height taken up by the bottom, I could just get it filled up into the neck and barely close the lid... Any ideas?

[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]Hello and good day, I have been planning on adding "cryo" Liquid nitrogen quench to my Heat Treat line up.. With the addition of stainless steel to my current offerings. So this is the next step to make sure the SS steels have the proper RC and toughness. As well as edge retention. [/FONT]

[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]Based off my limited experiance with this cryo treatment. I dont think it makes and significant difference with to my current carbon damascus mix. And if I understand correctly the SUB ZERO treatment benefits most stainless steels. With a notable gain toughness as well as additional hardness and edge retention. We have also started making a new damascus combination, of O1 an L-6. Which if I understand correctly will benefit from being Cryo quenched.. [/FONT]

[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]I have spent some time researching this and found a couple of great options for my new cryo tank. As well as tons of info on the subject on line. I talked to another knife maker that I have much respect for. He was very kind and open, sharing some important info with me so I make a informed purchase on the storage tank. He is currently doing cryo and has done much testing on many of the NEW SS steels. I gained more info from 1 call then I did searching the internet for 15 hours reading on the forums. So I need to say THANKS!!!! you know who you are. I appreciate your time and advise.

This is gona be fun!! [/FONT]

[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]This is a obsession, As most of you know. Proper Heat Treating is just as important as the steel type.. If not even more important! As a maker, I am always trying to refine my process and testing.. and learning.. There is room for improvement, and I intend to find it. This is the next step in my evolution. I know there are some here that have much more experience with this, and I welcome your comments and hope to learn as much as possible about this process B4 the new Dewar arrives.. Im just opening the door on the subject and starting to learn.. So please share your experience.[/FONT]

[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]Selecting the right tank turned out to be the easy part. The hard part was finding it at a good price! The price for a new tank was WAY out of my reach. So the search continued. Ebay and Craigs list, all the forums etc.etc. I finally found my tank.. A used 34L tank with a neck tube opening of over 3.5" For the TALL kitchen knife blades and large choppers! [/FONT]

[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]The LN tank is on its way to me and Im jazzed! Thanks to EVERYONE who gave me some help and advise, I hope to one day be able to return the favor or share or help someone else by passing along the same advise and info! [/FONT]

[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]God Bless[/FONT]
[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]Randy[/FONT]

[FONT=verdana, geneva, lucida, lucida grande, arial, helvetica, sans-serif]edit : I have gathered a bunch of different stainless steels over the last few months. Also a RC tester. Let the fun begin! On a side note, we are still working on mastering Stainless Damascus.. Which will also be Cryo treated! Yep, Im obsessed or CRAZY! lol possibly a little of both![/FONT]
__________________ I think I have that same tank Randy. I actually have two wide neck ones - a 20l with 3 3/4 neck and 19" deep - and the 34l with 3 5/8 neck and 23" deep (inside). I also have a few 20l with necks about 1 7/8. To be honest, there isn't a lot of difference in performance. The narrow neck ones will hold an unused charge for about 7 - 8 weeks. The 20 litre wideneck gets about 5 weeks nomatter how much or little I use it. I just got the 34L a few weeks back, but it seems to be at least holding it's own just fine after a couple weeks of liquid nitrogen.

A few hints are in order. It's good to put the tank on cardboard or something to prevent wear. Also, try to refill before it is completely empty. The expansion / contraction is not good for the tank life. You can hang most blades by a length of tie wire, but it's nice to have a tube holder for those times there isn't a hole in the blade to hang from. Liquid Nitrogen isn't as nasty as you might think. Yeah, it's downright bad to bathe in, but if a bit spatters on your sandles or your hand, you'll hardly notice. Cold blades are easily handled with welding gloves or insulated winter work gloves.

When going from cryo to temper, I either wait 20 minutes till they thaw, or I use a slow ramp (20 min) to get them up to 100F and then temper as normal.

Oh yes, these are not dry transport units. When transporting them in a car or van, I seatbelt the tank in place - and avoid turning the car upside down.

Rob! Rob, Thanks for the info. I think we may have the same Dewar's 3 5/8 and 23 deep 34L sounds about right!!! There are alot of options out there. Based on the info I had, My main things were a newer Dewar with a 3" + opening, and in good condition.. It took me some time to find one that looked good at a price I could manage! It seems the ones that were in my budget, all looked like they were used hard. Farm used, you know. driven around in the back of a farm truck. collecting and delivering samples. etc.

This one appears to be lightly used, and shows almost no signs of being bounced around. all the paint is there and no dents or duct tape! lol Funny what some people try and sell. I really did see a Dewar with tape holding it together for sale recently! LMAO!

I am anxious to start running some tests and to learn the new steels and what they have to offer! I have selected a couple of steels that I think will be a good starting point.. Its very exciting! And opens up alot of steel possibly to me.. I honestly like this part of the journey as a maker. I have said it before and will say it again. The journey is often the best part of the process. That said, I am always happy to get help or advise and appreciate it when someone takes the time to help guide me. So I dont fall in the same hole they have already encountered. Wasting time and energy or money.. For that, I am very grateful!!

Thanks for sharing and taking the time to post! Much respect. Great tip about transporting. I will Buckle it up and try and keep the rubber side down.