New K40 User - Water Cooling

Just got a new K40 Mini from OMTech. Added Air Assist and a Mini-Gerbil Controller Card and removed the Air Scoop.

I’m water cooling via a bucket with 4 gallons of distilled water. I previously hadn’t done tons of research on water temp and my temps have been right on 20C and I saw it once hit 21 C on a short burn.

Seems the OH MY GOD temp is over 20 C.

That being said I see that most people out there don’t have $500 chillers and just use the bucket method as I do.

I have read more than I want to about water temps but want to know the Real World, practical application of bucket cooling from people like me who may run at 21 C for a moment or two.

I understand that tube life can be shortened, I get that and without trying to be offensive a lot of internet experts are just that. Internet experts.

My device will probably always be a hobby device and not a production device. If I were running a widget for production I’d buy a $500 chiller or even better a $3000 machine from somewhere.

In a hobby environment, if you hover around 20, 21 C what are the real implications of doing that. I don’t have enough time on my machine (less than a week) to have the experience.

I guess what I’m looking for is someone who has used the machine a few years with bucket cooling who can say “Don’t do that” or “It works for me and I change my tube under normal wear and tear”.

Without rambling on too long 68 degrees roughly a couple degrees under most interior household temps. At 5AM I checked my bucket temp and it was 18C (spare room, heater vent closed partially). Temp theory says that now is the time I should work.

I have been chilling my water with ice packs and I can operate it seems just over 20 (20.4 or 20.5) most of the time.

Sorry for rambling but I’m just curious if there are long term bucket cooling users out there and how they manage.

Welcome among us @hagensieker,

short answer: the best is the enemy of the better ;-))

don’t bother too much a little xtra in temp, if the optimal temp is about 18°C a 3-4°C off both way is not a big deal, I have done more than that. just try to add some frozen bottles in your bucket. (keep the same water volume compared to ice cubes and easy to put back/swap in the freezer)
I rather save the budget to have a spare tube and some fresh drinks.
K40 is not a production machine, it’s entry level machine with low cost philosophy, our community did make it from “rubber stamp toy” to a usable machine for hobby. Thanks to western Hardware/software.

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Thanks. That was kind of my thoughts regarding the temps. I don’t see how 1 C could affect a whole lot under a low load. I’m reasonably certain I can keep the machine at or near 20 C but of course it is winter here.

I have an Ortur Laser Master 2 and I do most of my creative stuff on there. I just wanted the K40 to cut some stuff that the Ortur couldn’t do cleanly. Now that I have the K40 I want to push a little and see what it will do.

I agree with you that it isn’t a production device. I’ll buy any toy that comes along, one only needs to look around my house to see that but I can’t see buying a chiller that costs more than the machine itself. Heck I’d rather just buy an expensive, polished machine.

For me the K40 is about the mods and hacking around with it and I’ll crank out a breadboard here and there and make a little lunch money.

Thanks for your response.

The point of targeting the 18-20°C range is to give you room for the inevitable blips outside that range. Inevitable especially if you aren’t running some sort of closed-loop system, like running a refrigerated cooler. I’d be shocked if hitting 21°C caused harm. I think our Cooling the K40 laser tube article probably could use more nuance on this. It’s hard to get the right nuance simultaneously both for folks who are highly attuned to operational limits and those who think that 30°C is pretty close to 20°C so it shouldn’t matter. :relaxed:

Tubes age by loss of output power and I understand that CO accretion is a key factor in this aging. My understanding is that if it’s too warm, more of the CO isn’t converted back to CO2, aging the tube faster. Consistently running at 25°C is probably bad for tube life, 30°C is probably really bad for tube life. Ultimately, the temperature of the water in the bucket isn’t what matters; it’s just easier to measure than the temperature inside the tube… :relaxed:

@StephaneBUISSON, to your point about entry-level, I think that I may have made the cooling intro document too discouraging. :grimacing: That’s a hard balance; I don’t want to encourage people to kill their tubes by not paying attention, either.


I am about to embrak on my own K40 adventure. What mysifies me about all the cooling implementations I am reading about is that no one seems to use a heat exhanger or radiator on their builds.
For about $30 you can get a Hayden trans cooler for 3/8" push-on fittings.

Add a couple of quiet PC cooling fans and put that in your cooling loop.

What am I missing ?

Mainly that the cooling would be limited by your ambient room temperature.