Here's My suggestion. Use the Aluminum Plates as a heat sync to clamp the knife in, and have the plates be in direct contact with the Dry Ice. This way the Dry Ice can cool the plates well below freezing and aluminum plates will disperse the heat of the blade over a larger area, mitigating much of the localized sublimation of the dry ice.
Good idea, I would take it a step further. Make an ethanol dry ice bath and soak the aluminum plates until they are the same temp as the dry ice, then use the plates for quenching. Alternatively, you could use liquid nitrogen but the dry ice ethanol bath should not boil when you put the aluminum in it. Alternatively, you could use copper plates with even better thermal conductivity than aluminum but they would cost more.
I agree. I put my plates in the freezer before I quench and it works great. The blade needs to be flat though, so you end up grinding the bevels are hard steel. It's how I make most of my knives, but it uses a lot of abrasives.
Mix your quenching oil with dry ice to get it really cold. 15w30 should freeze up at -55F and there are some specialist oils good to -85F. That should minimize the leidenfrost effect while providing good surface contact.
Aluminum plates are pretty darn effective at heat transfer. I wonder if it would act as enough of a heat sink to be effective if you were to pre-chill the plates in liquid nitrogen.
no need to super cool the plates with air quench steels you have plenty of time to get the blade under 1000f i use Al plates for all of my air quench steels. main benny is keeping the blades from warping. at one point i thouoght about putting a 1/4" copper plate on the face of my 1" thick al plates cause copper can pull the heat out faster. never got around to doing it
yeah lol. Those old youtube clickbait videos said stuff like that and got like 80 million views. Just to be clear I'm reminiscing about those old videos not trying to say anything about your high quality stuff. also happy new year :)@@NFTI
You might also try using dry ice to create a makeshift cryo fluid out of something like alcohol, acetone, or anti-freeze(not super healthy) by cooling the liquid down.
Exactly what i was thinking, and using flammable liquids doubles the value of the experiment - will the liquid flame at these temperatures? assuming you deal with the vapors of course...
ethylene glycol is better at the heat transfer, but kinda toxic. although propylene glycol might be a good idea. i know they break down rather quickly under high heat, so it may have unwanted side effects. make sure to attempt that in a well-ventilated space for safety reasons
The cooling rate is not only dependent on temperature differential, but also how much energy it takes to heat the material. Water is 4184 J/kgK, steel is around 350 J/kgK, so for every degree the water is heated during the quench, the steel is cooled around 9. The dry ice is around 55 J/kgK, and will (as it goes into gas form) rob almost a full K from the steel. It actually worked better than I expected. Is it worth testing not "press between blocks" but "crush dry ice, and stir a knife around in it" as well? That MAY allow a faster cooling.
Water is a surprisingly good heat sink. It might not be as cold as dry ice or liquid nitrogen, but it doesn't need to be. Even at room temperature, it can still sink a lot of the heat off of a piece of metal - which is itself a pretty good heat conductor.
Instead of using screws to hold the dry ice use plastic or cover the clamp in Styrofoam. Metal contact with dry ice makes it transition from solid to gas faster.
try blending up the dry ice till its like fine sand. then move the blade around in it. it would act more like a liquid then. maybe try a super cooled oil too. or even anti-freeze cooled till it becomes thick.
So if the problem is that when the dry ice sublimates and creates a pocket where the knife no longer has physical contact, then maybe you could use the dry ice to cool your aluminum plates before and during the quench. That way you get the benefits of the aluminum's thermal conductivity and the low temperature of the dry ice.
Instead of quenching the blade in either water or dry ice, try both at the same time. Also, make sure the entire blade can be submerged. You’re trying to cool it quickly to sort of freeze the atoms in place while in an excited state, letting it cool slowly would allow the atoms to settle like silt at the bottom of a pond. If the entire blade including the handle isn’t being quenched at the same time the heat from the handle can dissipate into the blade slowing the cooling process. Unless the metal is designed for it that can effect the outcome, by how much I can’t say with out doing some testing. The first law of thermodynamics states energy can neither be created or destroyed. So using a small amount of liquid heats up the liquid and slows the cooling rate. Try getting a larger container of water, like a fifty gallon drum and filling it with normal ice. The quench process involves the dissipation of heat and the speed at which it occurs. So I would assume (if you stuck to just using water), the initial temperature of the water just before the quench would effect the outcome. Try that. Not extremes like liquid nitrogen (which was still awesome, btw), just hot water, room temperature water, cold (ice) water, then maybe find a way to include dry ice in that experiment as well if you can. No matter what, be sure to use large quantities of water, not just gallon jars. Since the heat is dissipating into the water a larger supply of water would be able to absorb more heat from the blade at a quicker rate. Would heat treating it in a large cold water supply, like a deep pool work better? Dropping it in the deep end allowing constant surface contact with the metal while continuously passing through fresh cold water. Would cold water being poured over the blade work better for hardness? I’m sure it would warp the blade more. Try not using the same container of water that would warm up with the quench, but instead using a continuous supply of fresh cold water. Like flood coolant in a cnc lathe/mill. Also, even if quenching it in water makes it slightly harder, quenching it in oil treats the surface of the metal and makes it more resistant to corrosion. The tiny pores in the metal absorb the oil and help keep it from rusting. I’ve got an interesting welding project I’m working on that involves stainless and mild steel being tig welded together. If I can get a video put together at some point I’ll try to tag you. I just found your channel and I think it’s great. Stay curious, my friend. The most common phrase uttered after an unintentional scientific discovery is “That’s funny”, because the results were not intended or expected.
@darkmooink69 Yup. I've done some googling and regular salt water isn't that good. But there's other salts that work way better. Still looking through results for the best salt.
when you mix salt water and ice you get slurry with freezing temperatures lower then -20c, people used it to make ice cream before freezers. (the ice and the salt reacts creating freezing temperatures).
When using a hardness tester you get the needle as close to vertical as you can in one smooth motion, then rotate the dial to match the needle. Tapping on the adjustment knob might apply too much preload force on the piece. How it works is it has a standard preload force, it applies a test force, then it measures the difference between the initial indent at the preload force and how deep the test load force indented. It might not be a huge difference, but would be more consistent.
He didn’t grind the thick decarb off of his blade. He also didn’t use foil or anti scale to prevent the decarb from happening in the first place. It’s likely 61-63hrc in the core depending of the stainless alloy
Nate, you don't need something very cold. You need something with very high thermal diffusivity that can be applied with consistent pressure. These microstructural transformations happen in seconds. After the first ~10-15 seconds or so of cooling even in air, the hardness of the blade is set and further cooling won't really change it. Realistically, water is hard to beat for this. A fluid definitely can't be beat by a solid at cooling. No matter what fluid you use, you will want high flow and/or turbulence (but low air/bubble content) to mitigate the leidenfrost effect as much as possible.
I don't know if it was just for the video. But putting plates on the inside.. aluminum preferably. Then dry ice.. letting the aluminum plates come down to dry ice temp. Then squeezing them together while blowing compressed air. Thats the most effective way i can think of to cool down something fast.
This was a really well done experiment with the concept. My question is, can a metal be reheated and cooled again to harden it more or would that not work?
You can to a certain extent. Essentially heating up the steel causes the microscopic grain structure to expand, when it is rapidly cooled (or even slowly cooled for that matter) the grains shrink down and a microscopic crystalline structure of the steel is formed. There are different formations of carbon and iron in the steel, austenite and martensite that are made through the process of quenching. Martensite in particular is what gives it the hardness, wear resistance and strength. Reheating it would effectively cause the grains to grow again, removing the crystalline structure, but you could quench it again. I learned a lot of this from a couple material science classes I've had to take for my degree. If you watch shows like "forged in fire" where they make knives, they make this info easily digestible in the case of knife making, not necessarily metal-working as a whole.
In the lab to get an efficient heat transfer at the temp of dry ice we use a mix of dry ice and isopropanol. The isopropanol you should be able to get at paint store. Just break up the ice and put in enough isopropanol to cover the object.
With quenching the _speed_ of temperature change is what matters and the sweet spot speed for some notion of optimal hardness seems to be provided by the quenching oil (who would've thought?). However after quenching and getting it to room temp the speed with which you can _continue_ to quench becomes so slow that you can do it e.g. by simply putting the piece in the freezer (see so called ice hardened steel). So it would be an interesting experiment to quench as usual (with quenching oil) and then harden it further with freezer, dry ice, liquid nitrogen, etc., and see how hard (and brittle) does it get, however I think it is a situation of diminishing returns.
Hey idea for you, I've always wondered, if you could seal the surface of a piece of aerogel in a vacuum chamber, if it would hold the vacuum inside without collapsing. And if it was a large enough piece, could you make a lighter-than-air solid?
Since some metals react better quenched in oil could you freeze some oil or lard into a similar block? Might be interesting combining the cold with traditional quench.
Hay nate try cooling aluminium with dry ice and using that for the quench, Aluminium quenching is offen used with high warp risk so why not try that but super cold
How about if you super-cool the quenching oil with liquid nitrogen, liquid oxygen or dry ice and THEN quench the knife in the oil? Perhaps keep the temp of the oil down during the quench by keeping the cold substance applied the whole time.
If you use granular dry ice and acetone, you would have a slurry of super cooled liquid. The only issue would be if the acetone would ignite when being touched with the hot metal. The liquid would be more efficient at carrying the heat away.
Oil is also a good case hardening substance. Getting carbon into the steel improves hardness, which oil and leather dust do quite well. Oil doesn't stink as bad, though.
Could you try something like powderizing the dry ice, putting it in a tall glass, and stabbing the hot knife into it? I feel like that might work better than using solid blocks.
Hey Nate, what about trying a bucket of propylene glycol that’s been cooled down with a block of dry ice to just above its freezing point. Then remove the dry ice so the co2 bubbles don’t interfere when the knife is submerged.
Perhaps if the dry ice was cut or ground into the smallest possible pieces or even powdered the effect would be better. IDK if dry ice can even be pulverized and remain dry ice but if it can then I'd try quenching it in a bucket of dry ice powder.
Mildly dangerous so do it outside but the best bet is to put the dry ice chips in isopropyl alcohol and make poor man's liquid nitrogen. Use that to Quench or put oil in with dry ice as a heat sync.
Specific heat of dry ice is 815 J/kg C, while oil is more like 2000 J/kg C. I don't know that it's an exact measure, but that does say that dry ice's ability to "absorb heat" (i.e. cool the knife) is less than half that of oil (not taking into account surface contact of liquid vs. solid blocks) so it's probably not able to cool the knife fast enough to actually temper it... Out of curiosity, looked up water and it's 4186 J/kg°C, which would explain why it cools TOO fast and tends to cause cracks, etc.
I know nothing about steel hardening, but what if you put dry ice inside synthetic oil to cool it down, then insert hot blade. Would that cause the oil to catch fire, or quench.
It works with modern quarters but not as well as it does with actual silver quarters 1964 and earlier. But if you push the quarter into the ice long enough that it forms a Groove and stands up, the quarter will begin to vibrate and sing. It's a really cool effect. Doesn't do anything else, but it looks and sounds cool.
How about a mixture of graphene particles in oil? Try quenching in that, the graphene will help in heat transfer and oil won't vapourise as easily! And ofcourse the oil is cooled to it's minimum before it's too viscous to use!
Make a dry ice and acetone bath and quench in that. The acetone will remain liquid at dry ice temp, and I think it will give you the super fast quench you're looking for.
The best way to get the metal harder is to get liquid water 50 degrees below zero but also liquid with an antifreeze and the blade should be close to molten
In the North East you can get dry ice from welding supply stores. And instead of using blocks of dry ice find a media blasting company that uses dry ice to strip rust and paint. They blast small dry ice pellets at the material to be stripped. So you could heat up the knife and then use the media blaster to cool it. That should cool the knife but more importantly the dry ice blasting at the knife will blow away any Leidenfrost effect around the knife.
Have you tried a mixture of crushed dry ice and acetone? Or another less flammable liquid that won't freeze. Outside with a fire extinguisher of course.
If you need dry ice, go to your local welding supply store. Co2 is sold in dry ice form because it allows for large quantities of densely packed gas to be transported with ease. Co2 is mixed with argon and used as a shielding gas for MIG and TIG welding torches to prevent the surface of metals like steel from oxidizing quickly due to the extreme heats that the metal is subjected to.
4:45 If you live a place where dry ice is unavailable, you can (kinda) make your own. You need to empty a C02 extinguisher into a container of some sort, and then compress the C02 snow that come out of it as much as you can. It isn't perfect, end its expensive as heck, but it'll work in a pinch. It can also cool down a case of your beverage of choice to fridge temps in about 5 minutes. Also, you can probably order it online.
As liquid transfers heat faster than air (what the dry ice sublimates to), perhaps if you found a liquid with a high freeing point and dropped dry ice into it to cool it down, you could get better than normal oil quenching? Idk, just guessing
It might work if you use a knife blank without holes and squeeze it between two pieces of dry ice cut to the shape of the knife blank. That way you would maintain constant contact with the dry ice without having to keep moving it around.
cryovice :P nitrogen cooled dry ice, as part of the quench. so you have liquid nitrogen, with plates of dry ice, get them down to temp, and in a cryovice. when you add the knife, it will liquid quench, while also having the press of the dry ice to keep it straight, and keep the lidenfrost from forming as much.
Would something like a chilled 3M novec fluid be good to try? With the aim of the fluid boiling at say 50C to disperse heat, but obviously not as a violent as liquid nitrogen boiling so hopefully sufficient cooling? EDIT: the great thing about 3M novec fluid is there is a lot different variants with different boiiling temperature to try.
The dry ice would make less contact than any liquic because once it melts out a space, there is only gas cooling stufff. Unless the dry ice was smaller than the blade, you would just have a knife shaped hollow in the ice. Try it with two pieces of dry ice that don't touch eachother.
I'd recommend trying a conformed aluminum plate set with dry ice to draw the heat away; alternatively, a cheaper option could be to make a 'bath' of Dry Ice pellets and small chunks, so that the ice falls in towards the knife as it sublimates.
If you want a dry ice temperature quench, fill a large insulated container with isopropyl alcohol and dry ice until the alcohol is -78C. Alcohol doesn't freeze until -90C. You'll have a liquid at dry ice temperature for full coverage.
I remember seeing something (I believe on MythBusters) years ago where they tried hardening with used motor oil and I've always wondered how well that would work with a knife/blade. Perhaps you could combine this by getting extremely *cold* used motor oil or have a quenching tub that rapidly cycles the fluid through it for faster thermal transfer?
Aluminum plates with a heat sink style backside. Then get your hands on powdered dry ice. Where I am in Michigan we have a facility an hour away that I used to pickup from for work that you could get blocks, plates, chunks, and powdered dry ice from.
The main problem here is probably the steel you are using. Quenching makes certain steel expericence what is called a martensitic change. (en.wikipedia.org/wiki/Martensite) The Martensite is what makes the blade hard and the change in crystal-structure is what makes the blade bend permanently. Grain structure is also a factor, which is why the hardness is different in each place. There is a lot of science behind it. What you can try is to reheat the blade afterwards to different temperatures and then observe the hardness and maybe how much it will bend. I am sure the results will be something nice :D
Depending on the steel, these cryogenic cooled knives will have a huge grain structure and are brittle as pretzels. That's why you quench in warm oil and not cold water.
Throw the dry ice into a blender to make it into a fine powder, then quench the blade in the powder, this will cool the blade faster but may not offer the clamping ability of the flat pieces. So if it warps with just the powder try putting the dry ice powder in between your metal plates and then clamp it.
Put a few long price of dry ice in a quenching oil setup. The oil should become almost solid or super think, then quench and move it around like normal.
I would like to see how would it work if you nitrogen cooled the blocks of try ice bedore using them to quenching, so that they are not on the border of sublimating when they are cooling down metal but have some wiggle room. Also to try the same with nitrogen cooled normal (water) ice.
Use dry ice to cool alcohol or maybe oil. The trick is to have a large thermal mass that can transfer heat. In order to do that it needs to be in direct contact with the metal. A liquid is the best for that.
Try tu use cold oil vs room temperature. You also my try experiment with a copper sandwich as a razors blades are processed like this. Copper sandwich would transfer heat more effectively when quenched and it help with knife buckling.
Make 2 aluminum or copper "water blocks" and flow the liquid nitro through the block cooling it to extreme temps and then press the knife between them.
How about using Cooper plates instead of the aluminum? Or putting the dry ice on the aluminum plates to cool them way more and then put the knife in between the aluminum?
You really only need to quench the cutting edge of the knife well. When the edge is hard it prevents it getting dull. Or atleast that is how the japanese blacksmiths preferred to make their swords. So you could get better effect by by trying to cut the block of dry ice with a red hot knife.
Idk if you can do it with dry ice, buy maybe if you finely crush it and pack it with just a small tight space to stab the hot knife in you can get better results
I knew TH-cam's CC was bad, but not that bad. As soon as that red hot piece of metal hit that dry ice and started that high pitched screaming, the CC captioned it as "music".....
Hey Nate,Its so great to see you keeping up the legacy,What an amazing experiment,Would the result change if you shredded the dry ice into thin dust and then clenched in the blade in that? (kind of like dry ice snow) much love from greece!
I see the Layton frost effect while quenching in nitrogen wondering if Blocks of metal frozen by nitrogen and pressing knife between them would work better
Yeah, it's not just how cold something is, it's also thermal conductivity and material properties. Best bet would be cooling something else in contact with the knife. Also, your rig was a good idea but a vertical set of quench plates would be a bit better.
What about antifreeze which has been cooled with dry ice or one of the other cooling agents? Would want to breath antifreeze exposed to that much heath though. Maybe just cool water with the dry ice.
What if you built a radiator / refrigeration tubing on some aluminium plates where you pour liquid nitrogen or something & the aluminium plates are then super cooled & you quench it between the plates under pressure. And what if you used pressurised oil that constantly sprays. So maybe a waterfall or fountain of oil constantly flowing….
Solid to solid without a thermal medium is going to have a hard time conducting heat. I just think you can't get enough consistent pressure on the blade because the surfaces are not smooth. I think with the carbon dioxide sublimating you are just not going to get the thermal conduction you need to cool it fast enough.
The problem is none of the materials actually pull the heat out of the steal. In the case of the aluminum plates, the aluminum actually pulls the heat out of the steal. It's the same with using oil. Just cooling the steal is not effective at hardening it.
![[MV] A leap of faith...ความเชื่อใจครั้งสุดท้าย (From "Petrichor the series")](http://i.ytimg.com/vi/U1piZH2CNXA/mqdefault.jpg)
I designed this bushcraft utility knife! Would you like to get one? I want to see if people are actually interested in it.
Yep
I'll pick one up, love your craftsmanship and artistic flair.
For sure
What’s 2000°F in °c? Everyone else uses °c
1093°C @@CaptainW_rCrimes
Here's My suggestion. Use the Aluminum Plates as a heat sync to clamp the knife in, and have the plates be in direct contact with the Dry Ice. This way the Dry Ice can cool the plates well below freezing and aluminum plates will disperse the heat of the blade over a larger area, mitigating much of the localized sublimation of the dry ice.
Good idea, I would take it a step further. Make an ethanol dry ice bath and soak the aluminum plates until they are the same temp as the dry ice, then use the plates for quenching. Alternatively, you could use liquid nitrogen but the dry ice ethanol bath should not boil when you put the aluminum in it. Alternatively, you could use copper plates with even better thermal conductivity than aluminum but they would cost more.
That's pretty much what I was going to say. Aluminum is a great conductor of heat, but I think the Dry Ice is more of an insulator.
was gonna suggest the same. would be cool if Nate tries it and it works
Heat sink* for future reference.
I'd use plates of copper as a heatsink - I think that would work quite well - especially with the dry ice/ethanol idea
Good stuff
I think next step is dry ice on the aluminum plates to cool the blade instead of blasting with cold air.
I agree. I put my plates in the freezer before I quench and it works great. The blade needs to be flat though, so you end up grinding the bevels are hard steel. It's how I make most of my knives, but it uses a lot of abrasives.
copper plates that were cooled with liquid nitrogen before.
Or liquid nitrogen to cool the plates. But yeah. That'd be interesting.
Mix your quenching oil with dry ice to get it really cold. 15w30 should freeze up at -55F and there are some specialist oils good to -85F. That should minimize the leidenfrost effect while providing good surface contact.
I wonder what frizen oil looks like.
Lard. Frozen oil looks like lard/butter. It's essentially all the same stuff, with slight differences that change the melting temp. @@jwalster9412
This is what I was thinking. Now I am kinda curious if oil will boil like water does if you drop dry ice into it?
Just did a youtube search. People have tried it. Yes, the oil bubbles.@@willernst2721
lol i was just about to comment the same thing, doubt it would work better than just oil, but would be interesting to see the results
Aluminum plates are pretty darn effective at heat transfer. I wonder if it would act as enough of a heat sink to be effective if you were to pre-chill the plates in liquid nitrogen.
no need to super cool the plates with air quench steels you have plenty of time to get the blade under 1000f i use Al plates for all of my air quench steels. main benny is keeping the blades from warping. at one point i thouoght about putting a 1/4" copper plate on the face of my 1" thick al plates cause copper can pull the heat out faster. never got around to doing it
Quenching in cooled -100C ethanol might work, just make sure to do it in an inert atmosphere so it doesn't catch fire.
I'm so glad to see a "5000 degree knife thru anything" type of video in the year 2024. Its like seeing an old friend.
I'd be interested to see a 5000 degree knife, since that's way above the melting point of every knife steel.
yeah lol. Those old youtube clickbait videos said stuff like that and got like 80 million views. Just to be clear I'm reminiscing about those old videos not trying to say anything about your high quality stuff. also happy new year :)@@NFTI
@@NFTImaybe the knife is an exotic alloy?
You might also try using dry ice to create a makeshift cryo fluid out of something like alcohol, acetone, or anti-freeze(not super healthy) by cooling the liquid down.
Exactly what i was thinking, and using flammable liquids doubles the value of the experiment - will the liquid flame at these temperatures? assuming you deal with the vapors of course...
ethylene glycol is better at the heat transfer, but kinda toxic. although propylene glycol might be a good idea. i know they break down rather quickly under high heat, so it may have unwanted side effects. make sure to attempt that in a well-ventilated space for safety reasons
Lovely sounds at 1:58
The cooling rate is not only dependent on temperature differential, but also how much energy it takes to heat the material. Water is 4184 J/kgK, steel is around 350 J/kgK, so for every degree the water is heated during the quench, the steel is cooled around 9. The dry ice is around 55 J/kgK, and will (as it goes into gas form) rob almost a full K from the steel. It actually worked better than I expected. Is it worth testing not "press between blocks" but "crush dry ice, and stir a knife around in it" as well? That MAY allow a faster cooling.
YAPPER DETECTED
Water is a surprisingly good heat sink. It might not be as cold as dry ice or liquid nitrogen, but it doesn't need to be. Even at room temperature, it can still sink a lot of the heat off of a piece of metal - which is itself a pretty good heat conductor.
i love nates super good enough setup. like it works but barely and thats all it needs to do.
Instead of using screws to hold the dry ice use plastic or cover the clamp in Styrofoam. Metal contact with dry ice makes it transition from solid to gas faster.
this is by far the best attempt at this idea, never seen anyone use 2 blocks of dry ice along side a mount for them to perfectly cool both sides
try blending up the dry ice till its like fine sand. then move the blade around in it. it would act more like a liquid then. maybe try a super cooled oil too. or even anti-freeze cooled till it becomes thick.
Nice improvised knife ice press!
So if the problem is that when the dry ice sublimates and creates a pocket where the knife no longer has physical contact, then maybe you could use the dry ice to cool your aluminum plates before and during the quench. That way you get the benefits of the aluminum's thermal conductivity and the low temperature of the dry ice.
Instead of quenching the blade in either water or dry ice, try both at the same time. Also, make sure the entire blade can be submerged. You’re trying to cool it quickly to sort of freeze the atoms in place while in an excited state, letting it cool slowly would allow the atoms to settle like silt at the bottom of a pond. If the entire blade including the handle isn’t being quenched at the same time the heat from the handle can dissipate into the blade slowing the cooling process. Unless the metal is designed for it that can effect the outcome, by how much I can’t say with out doing some testing. The first law of thermodynamics states energy can neither be created or destroyed. So using a small amount of liquid heats up the liquid and slows the cooling rate. Try getting a larger container of water, like a fifty gallon drum and filling it with normal ice. The quench process involves the dissipation of heat and the speed at which it occurs. So I would assume (if you stuck to just using water), the initial temperature of the water just before the quench would effect the outcome. Try that. Not extremes like liquid nitrogen (which was still awesome, btw), just hot water, room temperature water, cold (ice) water, then maybe find a way to include dry ice in that experiment as well if you can. No matter what, be sure to use large quantities of water, not just gallon jars. Since the heat is dissipating into the water a larger supply of water would be able to absorb more heat from the blade at a quicker rate. Would heat treating it in a large cold water supply, like a deep pool work better? Dropping it in the deep end allowing constant surface contact with the metal while continuously passing through fresh cold water. Would cold water being poured over the blade work better for hardness? I’m sure it would warp the blade more. Try not using the same container of water that would warm up with the quench, but instead using a continuous supply of fresh cold water. Like flood coolant in a cnc lathe/mill. Also, even if quenching it in water makes it slightly harder, quenching it in oil treats the surface of the metal and makes it more resistant to corrosion. The tiny pores in the metal absorb the oil and help keep it from rusting. I’ve got an interesting welding project I’m working on that involves stainless and mild steel being tig welded together. If I can get a video put together at some point I’ll try to tag you. I just found your channel and I think it’s great. Stay curious, my friend. The most common phrase uttered after an unintentional scientific discovery is “That’s funny”, because the results were not intended or expected.
how about powdered dry ice for quenching and mix powdered dry ice with oil
How about a high concentration salt water quench? Not sure how cold salt water can get before it freezes but it's worth a try.
It’s only a few degrees difference. Sea water freezes at -2C
@darkmooink69 Yup. I've done some googling and regular salt water isn't that good. But there's other salts that work way better. Still looking through results for the best salt.
when you mix salt water and ice you get slurry with freezing temperatures lower then -20c, people used it to make ice cream before freezers. (the ice and the salt reacts creating freezing temperatures).
Those sounds made my day :D thanks mate needed it really badly :P
When using a hardness tester you get the needle as close to vertical as you can in one smooth motion, then rotate the dial to match the needle. Tapping on the adjustment knob might apply too much preload force on the piece. How it works is it has a standard preload force, it applies a test force, then it measures the difference between the initial indent at the preload force and how deep the test load force indented. It might not be a huge difference, but would be more consistent.
He didn’t grind the thick decarb off of his blade. He also didn’t use foil or anti scale to prevent the decarb from happening in the first place. It’s likely 61-63hrc in the core depending of the stainless alloy
Nate, you don't need something very cold. You need something with very high thermal diffusivity that can be applied with consistent pressure. These microstructural transformations happen in seconds. After the first ~10-15 seconds or so of cooling even in air, the hardness of the blade is set and further cooling won't really change it.
Realistically, water is hard to beat for this. A fluid definitely can't be beat by a solid at cooling. No matter what fluid you use, you will want high flow and/or turbulence (but low air/bubble content) to mitigate the leidenfrost effect as much as possible.
I don't know if it was just for the video. But putting plates on the inside.. aluminum preferably. Then dry ice.. letting the aluminum plates come down to dry ice temp. Then squeezing them together while blowing compressed air. Thats the most effective way i can think of to cool down something fast.
This was a really well done experiment with the concept. My question is, can a metal be reheated and cooled again to harden it more or would that not work?
You can to a certain extent. Essentially heating up the steel causes the microscopic grain structure to expand, when it is rapidly cooled (or even slowly cooled for that matter) the grains shrink down and a microscopic crystalline structure of the steel is formed. There are different formations of carbon and iron in the steel, austenite and martensite that are made through the process of quenching. Martensite in particular is what gives it the hardness, wear resistance and strength. Reheating it would effectively cause the grains to grow again, removing the crystalline structure, but you could quench it again.
I learned a lot of this from a couple material science classes I've had to take for my degree. If you watch shows like "forged in fire" where they make knives, they make this info easily digestible in the case of knife making, not necessarily metal-working as a whole.
Annealing
In the lab to get an efficient heat transfer at the temp of dry ice we use a mix of dry ice and isopropanol. The isopropanol you should be able to get at paint store. Just break up the ice and put in enough isopropanol to cover the object.
I watched some of his videos a while back and then took a break, and I can say that he has Certainly improved in Quality! Keep it up man!
With quenching the _speed_ of temperature change is what matters and the sweet spot speed for some notion of optimal hardness seems to be provided by the quenching oil (who would've thought?).
However after quenching and getting it to room temp the speed with which you can _continue_ to quench becomes so slow that you can do it e.g. by simply putting the piece in the freezer (see so called ice hardened steel).
So it would be an interesting experiment to quench as usual (with quenching oil) and then harden it further with freezer, dry ice, liquid nitrogen, etc., and see how hard (and brittle) does it get, however I think it is a situation of diminishing returns.
You could also use a bath of dry ice and acetone. Acetone has a freezing point of -94 °C, which is lower than dry ice's sublimation point of -79 °C.
Suggestion: Try freezing a thickness of water onto the dry ice. Sublimation effect should be reduced while maintaining a temperature of near -104 F.
Hey idea for you, I've always wondered, if you could seal the surface of a piece of aerogel in a vacuum chamber, if it would hold the vacuum inside without collapsing. And if it was a large enough piece, could you make a lighter-than-air solid?
Always amazing these experiments
Bladesmiths that are worried about a blade bending when cooled already used huge rectangular slabs of aluminium to do the quench.
Since some metals react better quenched in oil could you freeze some oil or lard into a similar block? Might be interesting combining the cold with traditional quench.
Try using heat transfer fluid for quenching. It should remove the heat quite fast. Hopefully, it's not too fast and breaks the blade
Nice, Can you try quenching it in ethanol?
Hay nate try cooling aluminium with dry ice and using that for the quench, Aluminium quenching is offen used with high warp risk so why not try that but super cold
How about if you super-cool the quenching oil with liquid nitrogen, liquid oxygen or dry ice and THEN quench the knife in the oil? Perhaps keep the temp of the oil down during the quench by keeping the cold substance applied the whole time.
If you use granular dry ice and acetone, you would have a slurry of super cooled liquid. The only issue would be if the acetone would ignite when being touched with the hot metal.
The liquid would be more efficient at carrying the heat away.
Oil is also a good case hardening substance. Getting carbon into the steel improves hardness, which oil and leather dust do quite well. Oil doesn't stink as bad, though.
Could you try something like powderizing the dry ice, putting it in a tall glass, and stabbing the hot knife into it? I feel like that might work better than using solid blocks.
if you want to get it cooled quickly put dry ice water and salt in a bucket and when you put the knife in move it around really quickly
2:45 Its like a vise, since it uses pressure to keep something in place, and its designed for dry ice. Its the Ice-Vise!
Hey Nate, what about trying a bucket of propylene glycol that’s been cooled down with a block of dry ice to just above its freezing point. Then remove the dry ice so the co2 bubbles don’t interfere when the knife is submerged.
Perhaps if the dry ice was cut or ground into the smallest possible pieces or even powdered the effect would be better. IDK if dry ice can even be pulverized and remain dry ice but if it can then I'd try quenching it in a bucket of dry ice powder.
Mildly dangerous so do it outside but the best bet is to put the dry ice chips in isopropyl alcohol and make poor man's liquid nitrogen. Use that to Quench or put oil in with dry ice as a heat sync.
Specific heat of dry ice is 815 J/kg C, while oil is more like 2000 J/kg C. I don't know that it's an exact measure, but that does say that dry ice's ability to "absorb heat" (i.e. cool the knife) is less than half that of oil (not taking into account surface contact of liquid vs. solid blocks) so it's probably not able to cool the knife fast enough to actually temper it...
Out of curiosity, looked up water and it's 4186 J/kg°C, which would explain why it cools TOO fast and tends to cause cracks, etc.
I know nothing about steel hardening, but what if you put dry ice inside synthetic oil to cool it down, then insert hot blade. Would that cause the oil to catch fire, or quench.
It works with modern quarters but not as well as it does with actual silver quarters 1964 and earlier. But if you push the quarter into the ice long enough that it forms a Groove and stands up, the quarter will begin to vibrate and sing. It's a really cool effect. Doesn't do anything else, but it looks and sounds cool.
How about a mixture of graphene particles in oil? Try quenching in that, the graphene will help in heat transfer and oil won't vapourise as easily!
And ofcourse the oil is cooled to it's minimum before it's too viscous to use!
Make a dry ice and acetone bath and quench in that. The acetone will remain liquid at dry ice temp, and I think it will give you the super fast quench you're looking for.
The best way to get the metal harder is to get liquid water 50 degrees below zero but also liquid with an antifreeze and the blade should be close to molten
In the North East you can get dry ice from welding supply stores. And instead of using blocks of dry ice find a media blasting company that uses dry ice to strip rust and paint. They blast small dry ice pellets at the material to be stripped. So you could heat up the knife and then use the media blaster to cool it. That should cool the knife but more importantly the dry ice blasting at the knife will blow away any Leidenfrost effect around the knife.
Have you tried a mixture of crushed dry ice and acetone? Or another less flammable liquid that won't freeze. Outside with a fire extinguisher of course.
If you need dry ice, go to your local welding supply store. Co2 is sold in dry ice form because it allows for large quantities of densely packed gas to be transported with ease. Co2 is mixed with argon and used as a shielding gas for MIG and TIG welding torches to prevent the surface of metals like steel from oxidizing quickly due to the extreme heats that the metal is subjected to.
4:45
If you live a place where dry ice is unavailable, you can (kinda) make your own.
You need to empty a C02 extinguisher into a container of some sort, and then compress the C02 snow that come out of it as much as you can.
It isn't perfect, end its expensive as heck, but it'll work in a pinch.
It can also cool down a case of your beverage of choice to fridge temps in about 5 minutes.
Also, you can probably order it online.
As liquid transfers heat faster than air (what the dry ice sublimates to), perhaps if you found a liquid with a high freeing point and dropped dry ice into it to cool it down, you could get better than normal oil quenching? Idk, just guessing
It might work if you use a knife blank without holes and squeeze it between two pieces of dry ice cut to the shape of the knife blank. That way you would maintain constant contact with the dry ice without having to keep moving it around.
I'd recommend making the dry ice contraption with spring loaded spikes that pull down, instead of a static setup like that. Great video
cryovice :P
nitrogen cooled dry ice, as part of the quench. so you have liquid nitrogen, with plates of dry ice, get them down to temp, and in a cryovice. when you add the knife, it will liquid quench, while also having the press of the dry ice to keep it straight, and keep the lidenfrost from forming as much.
Would something like a chilled 3M novec fluid be good to try? With the aim of the fluid boiling at say 50C to disperse heat, but obviously not as a violent as liquid nitrogen boiling so hopefully sufficient cooling? EDIT: the great thing about 3M novec fluid is there is a lot different variants with different boiiling temperature to try.
The dry ice would make less contact than any liquic because once it melts out a space, there is only gas cooling stufff. Unless the dry ice was smaller than the blade, you would just have a knife shaped hollow in the ice. Try it with two pieces of dry ice that don't touch eachother.
I'd recommend trying a conformed aluminum plate set with dry ice to draw the heat away; alternatively, a cheaper option could be to make a 'bath' of Dry Ice pellets and small chunks, so that the ice falls in towards the knife as it sublimates.
What about getting some oil, and chilling it with dry ice chunks and see if that does anything... need some constant contact with the blade.
Interestingly, quenching oil is usually heated before use, as the thinner viscosity helps it transfer heat faster.
If you want a dry ice temperature quench, fill a large insulated container with isopropyl alcohol and dry ice until the alcohol is -78C. Alcohol doesn't freeze until -90C. You'll have a liquid at dry ice temperature for full coverage.
Nates about to be getting a discount for dry ice at his local dry ice store.
I remember seeing something (I believe on MythBusters) years ago where they tried hardening with used motor oil and I've always wondered how well that would work with a knife/blade. Perhaps you could combine this by getting extremely *cold* used motor oil or have a quenching tub that rapidly cycles the fluid through it for faster thermal transfer?
Can you use liquid nitrogen to supper cool the aluminium plates when you press then down in between the knife and eliminate the need for air entirely?
Aluminum plates with a heat sink style backside. Then get your hands on powdered dry ice. Where I am in Michigan we have a facility an hour away that I used to pickup from for work that you could get blocks, plates, chunks, and powdered dry ice from.
The main problem here is probably the steel you are using. Quenching makes certain steel expericence what is called a martensitic change. (en.wikipedia.org/wiki/Martensite) The Martensite is what makes the blade hard and the change in crystal-structure is what makes the blade bend permanently. Grain structure is also a factor, which is why the hardness is different in each place. There is a lot of science behind it. What you can try is to reheat the blade afterwards to different temperatures and then observe the hardness and maybe how much it will bend. I am sure the results will be something nice :D
Depending on the steel, these cryogenic cooled knives will have a huge grain structure and are brittle as pretzels. That's why you quench in warm oil and not cold water.
Throw the dry ice into a blender to make it into a fine powder, then quench the blade in the powder, this will cool the blade faster but may not offer the clamping ability of the flat pieces. So if it warps with just the powder try putting the dry ice powder in between your metal plates and then clamp it.
You would have to work fast because of all their surface area of the crushed dry ice
Put a few long price of dry ice in a quenching oil setup. The oil should become almost solid or super think, then quench and move it around like normal.
I would like to see how would it work if you nitrogen cooled the blocks of try ice bedore using them to quenching, so that they are not on the border of sublimating when they are cooling down metal but have some wiggle room. Also to try the same with nitrogen cooled normal (water) ice.
Use dry ice to cool alcohol or maybe oil.
The trick is to have a large thermal mass that can transfer heat.
In order to do that it needs to be in direct contact with the metal. A liquid is the best for that.
you could try to build a metal plate to put in-between the dry ice and the knife and see if that works.
You could try just slicing back and forth into the dry ice, only hardening the cutting edge
Happy and Healthy New Year to Nate and all the Nate from the Internet viewers! Who's watching in 2024?
Try tu use cold oil vs room temperature. You also my try experiment with a copper sandwich as a razors blades are processed like this. Copper sandwich would transfer heat more effectively when quenched and it help with knife buckling.
What would be a good quench is propylene glycol cooled to -80 with dry ice
Make 2 aluminum or copper "water blocks" and flow the liquid nitro through the block cooling it to extreme temps and then press the knife between them.
How about using Cooper plates instead of the aluminum? Or putting the dry ice on the aluminum plates to cool them way more and then put the knife in between the aluminum?
i love this guy
Dry ice is also often sold in special effects stores.
You really only need to quench the cutting edge of the knife well. When the edge is hard it prevents it getting dull. Or atleast that is how the japanese blacksmiths preferred to make their swords.
So you could get better effect by by trying to cut the block of dry ice with a red hot knife.
Have you tried antifreeze with dry ice yet? That should be able to get MUCH colder than water or oil, and still resist boiling as well.
Idk if you can do it with dry ice, buy maybe if you finely crush it and pack it with just a small tight space to stab the hot knife in you can get better results
I knew TH-cam's CC was bad, but not that bad. As soon as that red hot piece of metal hit that dry ice and started that high pitched screaming, the CC captioned it as "music".....
Hey Nate,Its so great to see you keeping up the legacy,What an amazing experiment,Would the result change if you shredded the dry ice into thin dust and then clenched in the blade in that? (kind of like dry ice snow) much love from greece!
I see the Layton frost effect while quenching in nitrogen wondering if
Blocks of metal frozen by nitrogen and pressing knife between them would work better
Yeah, it's not just how cold something is, it's also thermal conductivity and material properties.
Best bet would be cooling something else in contact with the knife.
Also, your rig was a good idea but a vertical set of quench plates would be a bit better.
What about antifreeze which has been cooled with dry ice or one of the other cooling agents? Would want to breath antifreeze exposed to that much heath though. Maybe just cool water with the dry ice.
Can you use dry ice or liquid nitrogen to chill alcohol to the subzero temperatures then use that to quench the knife?
Maybe dry ice in oil that won't freeze at those temps it would kind of be a sim of the same temps but in a medium that will allow cooling!
Acetone is commonly used for dry ice baths in the labs. Could give that a shot.
Fire extinguisher service centers usually sell dry ice if you cannot get at the grocery store.
What if you built a radiator / refrigeration tubing on some aluminium plates where you pour liquid nitrogen or something & the aluminium plates are then super cooled & you quench it between the plates under pressure.
And what if you used pressurised oil that constantly sprays. So maybe a waterfall or fountain of oil constantly flowing….
Solid to solid without a thermal medium is going to have a hard time conducting heat. I just think you can't get enough consistent pressure on the blade because the surfaces are not smooth. I think with the carbon dioxide sublimating you are just not going to get the thermal conduction you need to cool it fast enough.
Huh, neat!
Perhaps the next iteration would be like a grinding wheel but dry ice?
next up acetone, cooled by dry ice. picked that up from some exotic pc overclocking.
The problem is none of the materials actually pull the heat out of the steal. In the case of the aluminum plates, the aluminum actually pulls the heat out of the steal. It's the same with using oil. Just cooling the steal is not effective at hardening it.