Water Chiller Question

[Walt Langhans]

Hey guys!

I ordered a Shenhui G460 with an RECI80W tube, along with the upgraded chiller (thanks for the advice Rodne) and I'm working on getting my ducks in a row and I had seen some where that some of you were using antifreeze in your water chillers. I was wondering if it ended up giving you any problems and if you where using straight antifreeze or mixing it? The laser will be kept in my garage which is insulated but not heated and it does hit freezing temps here in Atlanta, so it's an issue I need to do something about.

Thanks

[Michael Hunter]

One of the importers of Chinese lasers into the UK sells antifreeze for the job.
I don't think that it is amazingly special - if you read the blurb below, you should be able to work out what is needed.

Get ready for winter with antifreeze that is suitable for your laser tube.
This is an Ethylene Glycol based solution that is non-toxic and has corrosion, scale and biological inhibitors.
Dilute the LS Coolflow with de-ionised or distilled water at a ratio of 1:4.
LS Coolflow is suitable all year as it has more efficient heat transfer qualities than water alone.
It is easily disposable as it is non-toxic and biodegradable as well conforming to BS6580 and ISO9001 standards.

[matthew knott]

Ethylene Glycol-and non toxic not 2 words i would put together, dont drink it, side effects include death, only bonus is the antidote is alcohol (neat spirits like vodka, gin ),

Seriously though, There's not contact between the water and optical parts so putting some antifreeze in the system is a good idea, get some from local autoparts shop and mix it in, 4:1 is quite strong if it doesn't get that cold in the building the laser is in, you can get a cheap tester to check the freezing point. I would get it in ASAP as a frozen tube is going to be a dead tube.

[George Carlson]

The automotive coolants have flourescent dye, which is handy for leak detection, but only make a bigger mess for the laser engraver. I use coolant sold for TIG welding machines. It's very clean and pre-mixed and does not have any dye in it. It is also a very good di-electric, which would not be a bad thing for a laser. You can get it at most better welding suppliers.

[Duncan Crawford]

Walt,

Another option might be RV antifreeze -- non-toxic, and no dye-- just verified that via UV flashlight. It's normally used at full strength, good to -50F, but it can be diluted and it's easy to find at big box stores, RV dealers, TSC and similar. Haven't measured its conductivity-- not a critical property for RV water systems-- but it will affect holding tank sensor readings so I suspect it's not a great dielectric. Other than that, I'd second the TIG coolant from George.

duncan

[john banks]

We use a 5 year life organic acid technology antifreeze of the sort you find in a modern automotive engine, 50:50 mix with deionised water. Cheap and readily available, it has been in nearly a year and looks clean in our CW5000 and RECI tube. I went for longer life stuff just so I wouldn't have to dispose of common ethylene glycol antifreeze as it is toxic. Price and availability of non-toxic propylene glycol was poor locally and I wasn't sure about the lifetime plus anti-microbial properties.

Our workshop is insulated (except for the floor which has rubber matting on uninsulated concrete, walls and ceiling have 4" of mineral wool) but unheated except for occupant comfort when in use, so it could go a few days in mid winter, which here might drop the internal temperature to around freezing at worst (last winter was mild, lowest we saw was 6 degrees Celcius), but I don't need to worry about it. Record lowest outside temperature here is still comfortably above the freezing point of 50% ethylene glycol.

[Walt Langhans]

Thank for the info guys!