What size and make Cryo dewar should I get?

HHH Knives

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Hello, Im looking into purchasing a dewar and the options and available sizes are throwing me off.

My question is, What size and make should I get? I will want to be able to cryo large kitchen knife blades OAL 16" as well as use it for folders and other smaller fixed blades. But mouth opening as well as depth of canister are my concern at the moment.

Any advise of info you Dogs cane share would be appreciated.

Thanks
Randy
 
The ones I see only have a 2 inch opening as normal size. I know you can get small holder that have bigger opening and are at least a foot deep. Most dewars are rated on length of holding the liquid nitrogen. Older ones had glass lining and newer ones have stainless.
I have seen exampes where they use the big dewars for storage and put knives in the smaller ones with bigger necks and pour the nitrogen over the knives and let stand.
Brand names are not important just how long of holding time..
Ebay has several. Lab suppliers carry them. I run across the dewars used in semen storage. You might check them. Select Sires and ABS are a couple. Welding supply house some carry them.
I use a semen tank and for small items out them together in a holder and put in tank. larger ones I put on stainless wire and slowly lower into the tank until they are submerged.
 
Mike, Thanks for the help. I just about purchased one on ebay today a 22L tank and waited to be sure B4 investing the cash. It was a semen tank and had a mouth opening of 2 5/8" The only problem is, I didnt know what the inside height was. And I waited to long and another lucky dog got it!! :)

Using a separate tank to do the kitchen blades may be the best way to go about this. I have seen some wide mouth dewars with 2 day hold time. that hold like 5 liters. Good thinking, Now its going cost me twice as much! lol
 
Chart and MVE are 2 manufacturers that I know of. There may be more but those two are the majors ones that we buy our vessels from(though you probably wont be able to go direct). The larger vessel capacity, will help keep your N2 from gassing on as fast. I have 3 customer that use 10l vessels and they are always empty when they need them.
 
Yea, I have been looking at used large vessels/dewar and separate smaller year large enough for my kitchen knives to actually do the cryo quench in.

Also found a Dewar with a 2 5/8 opening thats 26 inches deep. That would probably be about PERFECT!! But again with the wide would evaporation will be a issue?
 
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Here are the stats on the one Im thinking of getting.





LN2 Capacityliters22
Working Timemonths4
Dimensions
Necktube


Height


Outside Diameter
in
mm

in
mm

in
mm
2.62
66

26
660

15
380




Weight
Empty

Full
lb
kg
lb
kg
25
11
64
29

Canisters
Length
Internal Diameter
Number
inches
inches
mm
11
2.0
51
3

Capacity
0.5cc straws (on canes)

0.5cc straws (bulk)
500

1360

 
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The evaportion does go out the neck but they all have a foam plug that goes in the neck. Some build a box and put a hot water tank insulation blanket around them to extend the life. Mine is a 10 week tank.Mine has a 2 inch neck. Some will go above 12 weeks.
The one you have a description of sounds good.
 
[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 phone 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!
smile.gif
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!
 
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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.
smile.gif
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. ;)

 
I transport mine on the back floor board. I slide the front seat forward then install dewar then slide seat back solid to lock the tank in place. Saves having any thing that can move and be a problem.
 
UPDATE!!!
I went to get my Oxygen tank filled at a local welding shop this week. When I picked the tank up I mentioned LN and asked if his supplier would bring it out and deliver If I have a Dewar waiting for him. As it turn out the LN delivery truck comes to our little town once a week. Best part is, they will deliver and the welding shop is just a few blocks from my home so transport shouldn't be a problem!!!

Up until today I was under the impression that the closest place for a fill up was a 40 minute drive one way. What a Blessing and even if the cost is a little higher then the other place. With gas at 4.00 a gallon and time being one of the few things I cant make. Ill gladly pay a buck or 2 more a liter for the convenience!!

Heck if I wanted to I may be able to even cut out the local welding shop and deal direct with the supplier. But I wont There great guys , good old boys! Every time I drop in to buy something I spend at least a hour chatting with them and hanging around. Shops like this are all but extinct in this day and age. :)

Im still super excited to start learning and working to make a better HT blade. The search for the perfect cutting edge continues!!! :D
 
The tank arrived today! Its HUGE! :) Somehow I didnt think it would be this BIG. But Im glad it made it safe and sound and ready to ROCK N ROLL!!!
 
WHAT! Thats crazy big!

I have my first LN delivery scheduled for this week and will start the journey of Cryo quenching! :)
 
Sorry, I got the dewar and had it filled and in my excitement forgot to update this thread! :)

It is very exciting I have been running HT tests as I find the time on some new steels! Stainless and carbons. So far I have Cryo quenched AEBL, CPM154, O-1, K390, and Elmax. and a few stainless damascus blades!! All with great results. The Cryo part is pretty simple, and I found Alpha knife supply has a pretty good resource for heat treat specs on many of the steels we like as knife makers! So I have started there and refined from there.

Heres a few photos of dipped some stainless damascus blades in the LN

and a couple of some finished blades that have had the Cryo added to the HT process.


God Bless YA
Randy
 

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