Antifreeze instead of water?


#1

Can the laser tube be cooled down with antifreeze instead of water.
I work from my garage in Minnesota (very cold)


Cold storage
#2

Ethylene glycol + intense heat source. I’m thinking potential for a melted GF.
Heat your garage.


#3

I’m in Minnesota as well, and not sure if you hit the other topics, but I’ve pretty much resigned that our conditions are pretty much inhospitable for glowforge.

Humid summers, frigid winters.

Simpler is usually better when it comes to many things.


#4

Is it not antifreeze supposed to exchange heat like in car engines and keep them cool?


#5

Why would ethylene glycol result in a melted GF? It cools your car quite nicely even in extreme conditions (I have driven in vehicles up to 125F outside in the middle east) and of course that coolant is touching the outside of your cylinder in your car which I imagine gets way hotter than a laser tube ever does… The bigger issue with pure EG is that it only has half the heat capacity of water (but a 50/50 mix is 75% pure water).

Now on a more pertinent issue is if is so cold as to require antifreeze you start to worry about electrolytic capacitor performance and degradation.


#6

Right, the principles are relatively the same, however there’s more to a GF that we need to protect from the cold besides the cooling system. Even replacing the fluid used with a more robust liquid, would do nothing against the overall cold over the whole unit on a day like today.

Power systems, processing chip, glass on the lid and the camara lenses. The stepper motors for the moving parts, all these things won’t work as well(or as well for as long) at significantly below room temperature, and we would run into condensation issues too.

Bring it inside, keep it room temp.


#7

I was thinking more in the case of an unlikely leak. The tube may not get hot enough to ignite it, but if it were to leak onto the working area the heat from a laser will take it past its flash point
111 °C (232 °F; 384 K). Or not, I do tend to think in terms of worst case scenarios.


#8

I was also think about running the GF for my garage for part of the year and then moving to the basement for the cold months.

But now this gets me thinking that i have never seen anything about the suggested operating temperatures.

@dan has it been determined yet what the max and min operating temps are.


#9

I would be more worried about doing damage from other things way before I worry about the slight mix of coolant.
Cooling 40watts is not that much heat and does not require much liquid exchange.
For example, I would be more worried about putting the GF in a location where cool surfaces could condense Thus void your warranty.


#10

Though the laser’s useful output may be 40W, it’s electrical efficiency will define the amount of waste heat to be dissipated. Given that the laser’s efficiency is likely only on the order of 20% (20% of pump power converted to useful laser light), it’s likely to be dumping more like 200-250W. While that’s still not a huge amount of heat, it’s plenty to ask a compact cooling system to dissipate.

“Typical” consumer devices come with a generalized expectation of “reasonable” operating temperatures. If you’re operating such devices in locations where the “average” (not necessarily a winter-hardened Minnesotan) person is comfortable working without gloves/hat/big boots/etc, you’re probably ok.


#11

You’re right, looks more like 800W at peek load.

I am 100% sure it will state in the manual that you should operate your GF in non-condensing locations only. (or void your warranty)


#12

@dan mentioned viscocity is an issue with glycol.


#13

Now I am curious to see precisely what will happen when freezing a tube…

My gut reaction was “If it is cold enough to solidify your water, you don’t really need cooling for the laser, problem solved!”

But of course the whole “water expands” thing would still be an issue. Hard to design around that one.


#14

Yeah, I’m only worried about what happens in the middle of winter if for some unknown reason the power goes out while we are away. Currently 3 degrees Fahrenheit, very windy, and the sun is still up. Also a FedEx delivery of the GF with an already coolant charged system in the winter. Probably need some sort of freeze protection.


#15

Wha? Your house freezes solid and you’re worried about your Laser cooling unit? How about the pipes bursting (lived that once) and then when it warms slightly flooding the house uncontrollably.


#16

Nah. Water is always turned off before leaving for more than one day during winter. Though our septic line did freeze once. Had quite a mess. The Glowforge space will be well within any temperature storage/operating limits unless something goes really wrong. But with 10,000 customers, really wrong will happen often.


#17

From an Oct 15th post, the units will ship filled. Depending on the shipper to maintain above freezing conditions in shipping containers trucks and aircraft probably is out of their control, so it would not be a good idea to ship them with just plain old water. The first batch of shipping units might survive, since they are going out spring/summer. We frequently have to let shipments thaw out here when they come off the truck in winter, and I don’t even live in remotely the coldest climate they will be shipping Glowforges to.

The Oct 15th post
The cooling system will be shipped filled. Mark’s been testing coolants, so it may not be H20; I don’t know where he wound up.


#18

You have a drawback system? When we had a ski house up in the white mountains in NH we had to do a full drain back and fill the traps with potable antifreeze. Kind of a pain, but the house eventually went to outside temp (we had a timer that turned the heat on friday at noon, and if nobody came up that evening by 10pm it shut off - but that only brought the house to the mid 40s). If you came up midweek there as often ice in the house…


#19

Happened to me Sunday night in Missouri. I was at the cabin on Saturday and was returning on Sunday so I didn’t bother turning water off and draining pipes even though I knew it would get to single digits. No snow forecast. Whoops. Snow so I couldn’t get to the cabin (got to get my 4-wheel drive truck fixed.) so Monday it took a few hours of wood stove to thaw everything. Last year I learned that you have to empty your espresso machines in cold snaps. My Gaggia at the cabin froze and broke the water tubes. Whoops.


#20

Takes me back to the time I came home from the holidays to find that my pilot lights had been blown out by 100+ MPH wind gusts. Toilet was cracked in half from the block of ice that had formed there. House had been frozen solid for a week. And I had been SO looking forward to a hot shower for the last ten hours of my drive…