I got a LN dewar!

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Dec 31, 2011
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4,550
I have thought about using Liquid Nitrogen before for heat treating knife blades? Dry Ice slurry works just fine, but at $6 to $8 each time it gets expensive and a bit of hassle getting the stuff each time. I've always wanted LN, but never considered it due to cost. The dewars were in the $400 range (and still are for a 20 liter size), but a company put a 10 liter on sale for $200 shipped (ebay added $15 tax)

I called around about price to fill the 10 liter dewar. Prices ranged from $15 over in Mobile, to $62 locally in Robertsdale. I called 5 different places, the other 3 places were $40 to $45 to fill. Big spread in price.

I like the U.S. Solid dewar better than the other Chinese made dewars. Per this site https://ussolid.com/about-us/ the website almost seems to sound like "made in USA", but it doesn't say that exactly. Note the "make our own" and "established our own manufacturing" which could sound like "Made in USA", but could well mean they are still made in China, but under U.S. Solid's specs and supervision which would give a chance to be better than the usual "lowest bidder" from China. "In our own research (Spectroelectrochemistry, Femtosecond-laser spectroscopy, Photochemistry and Biophysics) we’ve encountered a series of overly expensive equipment that haven’t satisfied the demands put up to by modern research. We decided to make our own. After some careful analysis we’ve established our own manufacturing and are rapidly becoming viable competition in the North American market."

Anyway, the dewar got here yesterday, I went to fill it this morning. A 2 hr round trip, about 60 miles total. I went to the $15 fill place. I called to double check price, filling, etc. This morning on the phone the salesman told me $8 to fill the 10 liter dewar. Hmmm, that's almost too good to be true. I drove over, when I walked in he says "Sorry, I gave you the wrong price on the phone....... it's $5.50 including tax!" Wow I thinks. I paid the $5.50, took my dewar around back and they filled it.

Let's to see how long the dewar lasts with me playing, freezing grapes to watch them break like glass. AND see how many knife blades I can get treated with that dewar before it runs dry. If you've never played with LN you need to come over and freeze some stuff {g} Throw the frozen grapes on sidewalk and they shatter like glass.

The website says the 10 liter will hold LN for 60 days when it's not used. I'm hoping under normal use to get 30 days. I'm thinking I can profile up several blades during the next 20 days or so, then have them HT'd ready for bevels and finishing at my leisure. Anybody care to comment on expected holding time with the 10 liter dewar?

Ken H>
 
Man that's cheap. Cost me $200 to fill my 25 liter dewar in canada. I like the convenience though.

How many pieces of broccoli have died some you got on?

I get 3 months or so with my 25l dewar
 
3 months on 25 liter is pretty good, prorating that makes my desire of 30 days somewhat reasonable. I've not tried broccoli yet, just grapes. I'll bet broccoli would work good also.

Wow - $8/liter is pretty expensive. I'm not at all sure my next fill will be 50¢ or not. The ticket says "bulk price", and there is no way a 10 liter dewar would normally be considered bulk sales. I'm just hoping it won't go over $15 per 10 liter fill up. It is about 60 mile round trip. I left home right after 9am, and got back a tad before 11am so almost 2 hrs round trip including time to fill.

Like most of the other dewars it says 50mm. Only a 48.6mm X 2.5mm blade will slide inside. While a larger opening would be nice, a larger opening would reduce hold time. Like most things, it's all a compromise.
 
Congrats Ken
I have the same Dewar.


8 weeks without use to the last drop at the bottom sounds reasonable.

I was able to go 3 months with mine without use while still having an inch of LN at the bottom.

30 days of heavy use also sounds reasonable.

With moderate use should definitely be able to get a solid ~6-8weeks out of it.

H HSC ///
1.95" max blade width.





I have thought about using Liquid Nitrogen before for heat treating knife blades? Dry Ice slurry works just fine, but at $6 to $8 each time it gets expensive and a bit of hassle getting the stuff each time. I've always wanted LN, but never considered it due to cost. The dewars were in the $400 range (and still are for a 20 liter size), but a company put a 10 liter on sale for $200 shipped (ebay added $15 tax)

I called around about price to fill the 10 liter dewar. Prices ranged from $15 over in Mobile, to $62 locally in Robertsdale. I called 5 different places, the other 3 places were $40 to $45 to fill. Big spread in price.

I like the U.S. Solid dewar better than the other Chinese made dewars. Per this site https://ussolid.com/about-us/ the website almost seems to sound like "made in USA", but it doesn't say that exactly. Note the "make our own" and "established our own manufacturing" which could sound like "Made in USA", but could well mean they are still made in China, but under U.S. Solid's specs and supervision which would give a chance to be better than the usual "lowest bidder" from China. "In our own research (Spectroelectrochemistry, Femtosecond-laser spectroscopy, Photochemistry and Biophysics) we’ve encountered a series of overly expensive equipment that haven’t satisfied the demands put up to by modern research. We decided to make our own. After some careful analysis we’ve established our own manufacturing and are rapidly becoming viable competition in the North American market."

Anyway, the dewar got here yesterday, I went to fill it this morning. A 2 hr round trip, about 60 miles total. I went to the $15 fill place. I called to double check price, filling, etc. This morning on the phone the salesman told me $8 to fill the 10 liter dewar. Hmmm, that's almost too good to be true. I drove over, when I walked in he says "Sorry, I gave you the wrong price on the phone....... it's $5.50 including tax!" Wow I thinks. I paid the $5.50, took my dewar around back and they filled it.

Let's to see how long the dewar lasts with me playing, freezing grapes to watch them break like glass. AND see how many knife blades I can get treated with that dewar before it runs dry. If you've never played with LN you need to come over and freeze some stuff {g} Throw the frozen grapes on sidewalk and they shatter like glass.

The website says the 10 liter will hold LN for 60 days when it's not used. I'm hoping under normal use to get 30 days. I'm thinking I can profile up several blades during the next 20 days or so, then have them HT'd ready for bevels and finishing at my leisure. Anybody care to comment on expected holding time with the 10 liter dewar?

Ken H>
 
Thanks for comments - If I can get 4 to 5 wks with light use I'll be more than happy. Heck, $5.50 to fill is almost nothing, other than the trip. $8/liter that Scott has to pay - that's a bit tougher and would have to be very saving. deadboxhero: What do you pay for LN to fill your 10 liter dewar?

Maybe I'll be able to get 1.95" with a thin blade, but I do think my opening isn't quite that wide. I checked again and about 1.93" to 1.94" is all I can get without forcing.
 
It's pretty fun to make icecream with it as well, just pour and stir.

last fill was $3.50 per liter.

Last blade I did was 1.95" using my mitutoyo calipers to measure the blade in width at the widest point, I ground the blade height down to fit, I went back and forth from grinder to dewar on the blank before HT.

1.97" would not physically fit. Lots of back and forth.

So 1.95" was the max width size to slide into my dewar opening on the US solid brand Dewar without wedging into the opening shaft.





Thanks for comments - If I can get 4 to 5 wks with light use I'll be more than happy. Heck, $5.50 to fill is almost nothing, other than the trip. $8/liter that Scott has to pay - that's a bit tougher and would have to be very saving. deadboxhero: What do you pay for LN to fill your 10 liter dewar?

Maybe I'll be able to get 1.95" with a thin blade, but I do think my opening isn't quite that wide. I checked again and about 1.93" to 1.94" is all I can get without forcing.
 
Congrats Ken
I have the same Dewar.


8 weeks without use to the last drop at the bottom sounds reasonable.

I was able to go 3 months with mine without use while still having an inch of LN at the bottom.

30 days of heavy use also sounds reasonable.

With moderate use should definitely be able to get a solid ~6-8weeks out of it.

H HSC ///
1.95" max blade width.
Big bear ................IF you have unlimited number of blanks ready for LN , now many you think can be done with one full dewar ?
 
with an unlimited number of blanks ready to go - LOTS of them. Considering each needs to sit at least 30 minutes (just a good round number, maybe less for thin blades) and perhaps hang 6 at a time (depending on size of blade), you could get a bunch of blades from one dewar.

$3.50/liter - that's what one place quoted around here. One place was about $5.50/liter, and another $4/liter. None could come close to the one that quoted 50¢ to $1.50 /liter depending on which time I called.

Just dip some LN with one of the straws and pour into the ice cream mix? I'll have to try that. My granddaughter is coming for a visit next weekend, need to have it figured out by then {g}
 
It's pretty fun to make icecream with it as well, just pour and stir.

last fill was $3.50 per liter.

Last blade I did was 1.95" using my mitutoyo calipers to measure the blade in width at the widest point, I ground the blade height down to fit, I went back and forth from grinder to dewar on the blank before HT.

1.97" would not physically fit. Lots of back and forth.

So 1.95" was the max width size to slide into my dewar opening on the US solid brand Dewar without wedging into the opening shaft.

Ican do 1 7/8” in my Chinese dewar.
 
With heavy use (more opening and closing) than amount of steel being done (slipjoints) my 10
liter would go 4ish weeks and it was right around $20 to fill it.
Ken
 
Man we get hosed in canada. Much of our cost is an environmental fee. We have same the crap for dry ice. I tried to argue that most of the atmosphere is nitrogen and in the case of dry ice I breath the stuff out to no avail. It doesnt help that there's no competition where I am.

I actually considered making my own liquid nitrogen because why not. Common sense prevailed.

 
Scott - you did it again. Cost me an hour, not just watching the video but looking up cost and source of cyrocoolers to make LN. Actually for our use liquid air would work just fine since the purity of nitrogen isn't needed, just the cold temperature. Another idea is a "cold" freezer that holds temperature below -100°F.
 
With heavy use (more opening and closing) than amount of steel being done (slipjoints) my 10 liter would go 4ish weeks and it was right around $20 to fill it.
Ken
Looks like I'm going to get about the same storage time as you Ken. Today is a couple days over 5 wks and there still seems to be about 3 to 4" of LN in bottom of dewar, and I've only treated 6 or 8 blades. I checked this by putting a straw (ya'll know the SS "straws" that are used with dewar for semen storage) and it seems to frost up around mid point. This is only dipping straw into dewar for a few seconds. Left in longer I'm sure it would have frosted up all the straw. I "think" I could still treat a blade (small blade anyway) with the amount of LN in dewar. BUT - I'm happy with the 5 weeks, remember I played with the LN some, making ice cream, freezing grapes, etc. I'm sure I used well over a liter just playing.

The dewar is stored in the pasteboard shipping box that has a thin layer of bubble wrap around dewar which I'm sure helps a very small bit with storage. The dewar is stored in the A/V'd radio room that's kept around 74°F during day, and around 80°F or so at night. Let's see how much I have to pay this time to get it filled. Hard to imagine I can get the same $5.50 fill cost.
 
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Yep, I measured the temp right at the top, just inside the dewar neck and got -127°F. On down close to LN it was -223°F and it's still falling so the TC might actually be in LN, not sure. BUT, it's still plenty cold enough. I'm thinking I just might get 6 wks from this dewar, even with the ice cream I've made {g}

At this point, I'm VERY happy I got the dewar and started using LN. Other than $200 cost of dewar, LN is going to be a good bit less expensive than dry ice I was using.
 
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