Cooling quenching oil with dry ice: bad idea?

P.Brewster

P.Brewster

Joined
Jul 25, 2007
Messages
1,380
I'm often sequentially quenching a batch of knives (up to 20) and need to cool my tank of oil. I've built several effective systems involving exchanging the heat with a tank of cool water, but it's a hassle to set up and take down.

Because I'm lazy, recently I've just been placing sealed ice packs (the kind you put in your cooler) in the oil. This is effective, but also a bit of a hassle, because I need to clean the oil off when I'm done.

I'm thinking about dropping some chunks of dry ice into the oil. I would do this in between quenches, and I would wait for the dry ice to 'melt' (sublime) before I quench the next knife.

Tell me what problems you think this might cause. I'm thinking that the dry ice will probably put some water in my oil, but that should sink to the bottom. I'm wondering if the dry ice might cause explosive 'fountains' of oil, or something to that effect.
 
It won't be a problem, but it won't cool real effectively. As the dry ice begins to sublime, it'll form a jacket of CO2 around itself. You'd need to move it around quite a bit.

As for water and "explosions", well water won't be a big issue and explosions SHOULDN'T happen, but with dry ice, things can get crazy at times. The biggest issue would be if the dry ice block had a fault in it and it fractured suddenly.

Just my thoughts
 
P.Brewster said:
I'm often sequentially quenching a batch of knives (up to 20) and need to cool my tank of oil. I've built several effective systems involving exchanging the heat with a tank of cool water, but it's a hassle to set up and take down.

Because I'm lazy, recently I've just been placing sealed ice packs (the kind you put in your cooler) in the oil. This is effective, but also a bit of a hassle, because I need to clean the oil off when I'm done.

I'm thinking about dropping some chunks of dry ice into the oil. I would do this in between quenches, and I would wait for the dry ice to 'melt' (sublime) before I quench the next knife.

Tell me what problems you think this might cause. I'm thinking that the dry ice will probably put some water in my oil, but that should sink to the bottom. I'm wondering if the dry ice might cause explosive 'fountains' of oil, or something to that effect.
Click to expand...

I don't know if the co2 would dissolve in the oil, if it did, you would have quench oil soda pop.

If you made a cooling pump with some coils that are in the oil, then run water through the coils and put the dry ice in that water.
 
A transmission oil cooler radiator and a 12V radiator cooling fan plus a 12v transmission oil pump will make a great quench oil cooler. Add a thermostat to it and it will automatically turn the fan on at 130F. All these can be bought at the auto parts store of scrounged at the auto junk yard.

To make an even better quench tank, bring the oil return straight up in the center of the bottom and draw the warm oil off about 3" below the top surface. Use a pump with a couple GPM flow rate and 3/4" pipes and tubing. This will make an up-rushing quenchant flow that really quenches a blade well. Add the cooler above to the circulation lines and you have an industrial grade quench tank that will do as many blades as you want. Add a small heater rod with a simple temperature controller and the tank will warm the oil for you, too. The same controller may be used to run both the heat as well as the cool in many cases.
 
Stacy E. Apelt - Bladesmith said:
A transmission oil cooler radiator and a 12V radiator cooling fan plus a 12v transmission oil pump will make a great quench oil cooler. Add a thermostat to it and it will automatically turn the fan on at 130F. All these can be bought at the auto parts store of scrounged at the auto junk yard.

To make an even better quench tank, bring the oil return straight up in the center of the bottom and draw the warm oil off about 3" below the top surface. Use a pump with a couple GPM flow rate and 3/4" pipes and tubing. This will make an up-rushing quenchant flow that really quenches a blade well. Add the cooler above to the circulation lines and you have an industrial grade quench tank that will do as many blades as you want. Add a small heater rod with a simple temperature controller and the tank will warm the oil for you, too. The same controller may be used to run both the heat as well as the cool in many cases.
Click to expand...

Yup I've done this already, for the most part - although in my experience it takes a LOT more cooling BTUs than you're suggesting to keep up with an 8oz knife being quenched every 3 minutes or so. Specifically, the GPMs on any affordable oil pump is just not enough.

What I've done so far is listed below. Rev 1 and 3 worked fine - I'm just hoping for something more simple and faster to set-up/take-down because I don't have the space to leave it installed.

Rev 1: 5-gal bucket of cold water. Water is pumped through a stainless steel heat-exchanger that is immersed in the oil. The heat exchanger was a coil of 50 feet of 3/8" OD tubing. Worked great.

Rev 2: The same as rev 1, but in reverse - oil is pumped through a heat-exchanger that is immersed in a bucket of cold water. I tried three different pumps, none gave me a flow that was fast enough to keep up with the heat load (I went as high as 7 GPM). The bottleneck was obviously the heat exchanger. I used the up-flow plumbing configuration that you mention here.

Rev 3: Quench tank is placed in a tupperware full of cold water. Water is circulated with a water pump, and the oil is circulated with a drill-powered pump that I built that was configured to create an upward flow. The heat is exchanged through the wall of the quench tank. Worked great.
 
I think the solubility of carbon dioxide in water and in oil is similar, so after cooling there will be some gas left in the oil. But, at 120 - 150 F, it will probably be negligible. The biggest danger will be from splashed hot oil during the cooling and as was noted the heat transfer will be poor, unless you can get really small bubbles from the bottom of the tank. If you were to make a metal container with a lot of small holes in it that could hold the dry ice and not burst, it might work if placed in the bottom of the tank.
 
OK, been following this read but was waiting for more info. Nobody's asked the questions I expected, so I'll ask.
1. How big is your oil tank currently?
2. What temperature are you keeping/wanting to keep the oil at when quenching?

A 12" x 18" transmission radiator with 110GPH pump will reduce 120°F water about 10° F with a 75w fan blowing through it at room temp. Oil should cool even more. That's more than enough to keep up with the heat input from the knives at 3 minute intervals.
 
Oil volume is the primary question to ask in this situation.

When we quench Bubble Jig clamps its done in 30 count. We were having over heat problems when quenching 20 of the clamps when using 5 gals of Parks AAA. When the volume was increased to 8 gal. we found we could quench 30 clamps only raising the oil temp from 75 to 135 FH, 2 degrees per clamp. We have a circulating pump and a copper cooling coil if needed but as of now, it has not been used.
 
Atlas Knife Company said:
OK, been following this read but was waiting for more info. Nobody's asked the questions I expected, so I'll ask.
1. How big is your oil tank currently?
2. What temperature are you keeping/wanting to keep the oil at when quenching?

A 12" x 18" transmission radiator with 110GPH pump will reduce 120°F water about 10° F with a 75w fan blowing through it at room temp. Oil should cool even more. That's more than enough to keep up with the heat input from the knives at 3 minute intervals.
Click to expand...

My oil tank holds about 6 gallons of Parks 50. My short-term goal is to simply keep it in the advised operating range, which is ambient to 120°F. Long term, I'd like to have more precise control.

I believe what you say about a 110 GPH pump - am I correct that they don't get much cheaper than the following? ($190 to $260)
http://www.summitracing.com/parts/til-40-524
http://www.westmarine.com/buy/reverso--gp-311-2-1gpm-gear-oil-pump-12v--12792198
http://www.westmarine.com/buy/reverso--op-6-3gpm-reversible-impeller-pump-12v--12792164

The last pump I used had a max rating of 7 GPM (420 GPH) for water - but the flow rate with oil, through the heat exchanger I was using, was insufficiently low.

Again, I have built successful chilling systems as outlined in my 02-19-2016, 04:41 PM comment - my question here is how to accomplish the goal without so much complexity and set-up/take-down hassle. However, it looks like a pump/radiator might be the best long-term solution, and something I could mount to the quench tank.
 
Last edited:
I know Dave Larsen used a cheap garden pump in his tank, and it works fine with parks.
http://www.bladeforums.com/forums/s...uench-Tank?highlight=larsen+quench+tank+build

These are the $8 pumps you can get at HF:
http://www.harborfreight.com/158-gph-submersible-fountain-pump-68396.html

Here's a thread discussing why such a pump probably won't work(even though empirical evidence proves otherwise):
http://www.bladeforums.com/forums/s...uench-tank?highlight=larsen+quench+tank+build

I would expect that a 158GPH pump would probably be about half volume, or around 80GPH with parks. Still, the difference in price makes it worth it. Buy two, just in case the super cheap part dies, and you'll still be ~$180 cheaper.
 
I wonder if you could just use 2-3 smaller quench containers instead? Also, would it be possible to quench a couple blades at once? I'm guessing you'd want to keep a decent sized gap between them.
 
just a shot in the dark, ever heard of a wort chiller? beer geeks go to extreme measures to cool down that boiling wort(beer) as quickly as possible, might be worth checking out some of those systems. Bonus is they are removable and just hook up to a hose/faucet.
 
I know guys that make applejack in a mix of dry ice and rubbing alcohol. I wouldn't use rubbing alcohol, but a bath of antifreeze and dry ice at the bottom of your quench tub might work.
 
Atlas Knife Company said:
I know Dave Larsen used a cheap garden pump in his tank, and it works fine with parks.
http://www.bladeforums.com/forums/s...uench-Tank?highlight=larsen+quench+tank+build

These are the $8 pumps you can get at HF:
http://www.harborfreight.com/158-gph-submersible-fountain-pump-68396.html

Here's a thread discussing why such a pump probably won't work(even though empirical evidence proves otherwise):
http://www.bladeforums.com/forums/s...uench-tank?highlight=larsen+quench+tank+build

I would expect that a 158GPH pump would probably be about half volume, or around 80GPH with parks. Still, the difference in price makes it worth it. Buy two, just in case the super cheap part dies, and you'll still be ~$180 cheaper.
Click to expand...

I appreciate your thoughts, but it seems like mine are falling on deaf ears. To reiterate, I've used 3 different pumps - the last pump I used was 420 GPH. It pumps oil just fine, but the flowrate when pumping through the heat exchanger is not sufficient to drop the oil temperature as needed. The threads you linked to are not covering the topic of pumping oil through a heat exchanger.
 
timos- said:
just a shot in the dark, ever heard of a wort chiller? beer geeks go to extreme measures to cool down that boiling wort(beer) as quickly as possible, might be worth checking out some of those systems. Bonus is they are removable and just hook up to a hose/faucet.
Click to expand...

Yup, a wort chiller is what I used in my first successful build. I'm hoping for less complexity and less set-up time.
 
What size fan did you use on your radiator? I have a 6 amp 12v fan that blows about 800 CFM to cool it off. A bigger pump don't cool it faster, if anything it's slower. It's the fan that makes a difference when it comes to cooling.
 
Atlas Knife Company said:
What size fan did you use on your radiator? I have a 6 amp 12v fan that blows about 800 CFM to cool it off. A bigger pump don't cool it faster, if anything it's slower. It's the fan that makes a difference when it comes to cooling.
Click to expand...

I used the pumps with a coiled stainless steel liquid-to-liquid heat exchanger ('wort chiller') rather than a liquid-to-air heat exchanger (radiator). I'm hesitant to dump more money into the heat exchanger/radiator concept unless someone can say from experience, rather than theory, that it works. Are you using your radiator to cool oil? If so, what pump are you using?

On the other hand, it looks like dry ice is a 30 minute drive away, so I'm back a square one with this project. I'll continue to use one of the two successful set-ups in the meantime.
 
You must log in or register to reply here.
Back
Top