[SpacedCowboy]

So I'm about to set up the laser in the garage - after drilling the hole for the venting I'm hoping to have it up and tested this weekend. And then I thought of something....

I'm going to have a glass tube filled with water in an unheated garage and to quote the Starks, "Winter is coming"... There's a busy server-rack 20' away in the opposite corner (which has the reverse problem in the Summer ), and it's not *likely* to get below freezing in there, but it's possible. I really don't want the water freezing in the tube.

I have a CW-5000 chiller sitting in the box waiting to be installed. There doesn't appear to be any protection against freezing built into it either, so I'm wondering what the options are:

• Antifreeze. This seems to be problematic. According to 'lasergods' (really?) the conductivity is an issue, and RV antifreeze - which has the lowest conductivity - is prone to "excessive" bacterial growth. I've seen tig welder coolant suggested as a low-conductivity alternative, but that seems to be corrosive to some things, and I'm not sure if it would be a problem for the cooling system loop components.
  
• Warming the water. The tank of water is contained within the CW5000, so I doubt that's an option. If I get an inline heater, I'd still have to pump it through the system, and I'm not sure if the CW5000 would allow that (depends on which type of pump it uses itself)
  
• Draining the tube/chiller at the end of every session. That doesn't seem like a great plan.
  
• Warming the garage up. I guess I could put a space heater in there, but I'm not overflowing with enthusiasm for this idea either. Those things have been known to go on fire, and we do go on vacation in the winter...
  

All this assumes there's a temperature-monitoring system that can control an external pump/heater, but aquarium monitors have that down pat, and some temp. monitors can control relays like that too.

It also occurred to me that I could fork off the laser tube water circuit with a Y to the inline heater/pump, then join it back up with an inverted Y, so that I could protect the laser tube at least, but that might negatively impact the cooling circuit when the heater/pump aren't in use, one-way valves notwithstanding.

So, in a plea to the wisdom of crowds... What do y'all do ?

[Dtcrafts]

hi we use a 50/50 mix of distilled water and anti freeze all year round with no problems
it needs to be distilled water not de-ionised or filtered and then you wont get any growth in the tube.
the one thing you may get like we do is if the water goes below 5 degrees the CW 5000 will go into alarm state
al we do to correct that is to switch off and back on till it alarms again and keep doing that till the pump itself gets warm and heats the water slightly then you are good to go for the day
Dave

[MichaelHenry]

I just use a 1kW space heater in my unheated, partially insulated, attached garage in the Chicago area. The tube has survived 2 years like that with no problem. TL Nova 24 and CW-5000 chiller.

[SpacedCowboy]

hi we use a 50/50 mix of distilled water and anti freeze all year round with no problems
it needs to be distilled water not de-ionised or filtered and then you wont get any growth in the tube.
the one thing you may get like we do is if the water goes below 5 degrees the CW 5000 will go into alarm state
al we do to correct that is to switch off and back on till it alarms again and keep doing that till the pump itself gets warm and heats the water slightly then you are good to go for the day
Dave

Ok, that sounds good.Do you have a recommendation for any particular antifreeze ? I've seen posts saying to not use car antifreeze, but apparently RV antifreeze is not as corrosive ?

I just use a 1kW space heater in my unheated, partially insulated, attached garage in the Chicago area. The tube has survived 2 years like that with no problem. TL Nova 24 and CW-5000 chiller.

I did think about using one of these with a halogen or infra-red heat lamp or two.

Thanks for the feedback guys

[Dtcrafts]

hi we just use ordinary standard anti freeze, have done for several years with no problems at all
Dave

[fixtureman1]

I have been using RV antifreeze in my lasers for 5 years now