Im seeing several machines for sale because their tube cracked due to water freezing.
With that said, ideas on ways to prevent this?
Aside from draining water out when done, can antifreeze be added to the distilled water?
Thoughts?
anti-freeze â yes. for me it works flawlessly for many years. also add a nice pink color to the water, cool effect with the laser glowing.
I think the generally accepted wisdom these days is that automotive antifreeze is bad because of its high electrical conductivity. Thereâs several good articles floating around on the subject.
Hereâs one:
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Fortunately I came across the article that Hank has linked to before I filled my system up, as I was going to use deionised water and antifreeze. I now have distilled water (why is it so difficult to find in the U.K.??) with a capful of bleach. I also intend to fit a couple of low wattage tubular heaters to prevent freezing this coming winter.
I have a temperature monitor (Arduino controlled) that turns on when the air temperature falls to 37 degrees F and turns off when the temp rises above 42 degrees. The controller turns on both a 25W Aquarium heater in my reservoir tank and the coolant circulator pump. I only use distilled water. This setup has worked for three years. Note that it will fail if I lose power AND the temp falls below freezing. 
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ok, so obviously Iâd feel more safe with a Non Powered solution if loss of A/C power.
Great article, but his Secret Recipe doesnât include anything to prevent freezing, and loss of a $1k tube.
Not really sure why conductivity even matters, as the âcoolantâ is on the outside of the tube that carries the electrical current, correct?
If you have a crack in your inner tube, then yes, conductivity would be a serious issue.
If Anti-Freeze is ânot recommended for any reasonâ, then just turning on the pump should prevent the water from freezing, as flowing water has diff temps throughout the system and gives an avg of the highest and lowest temp, not static water temp around tube. However, this only works with power.
So for a 5 gal system, is a 50/50 Antifreeze not a good idea?
2.5 gal of Distilled Water & 2.5 gal of RV Antifreeze (pink) ?
Quick search shows 50/50 works to -35°F / -37.2°C. That is WAY coolder than most laser tubes would be subjected to, so maybe an 70/30 would be better than nothing.
Trivia / What temp is F and C the same? -40°F = -40°C
Because the voltage is high enough it can punch through glass if thereâs something conductive right up against the other side.
Ok, that makes sense about it punching thru.
So besides modifying the water, what about the laser tube cabinet?
Can thin insulated foam board be put under the cabinet, and on the top and side of lid ?
I assume the water inside the rubber hoses isnât the problem, just the horizontal water in the tube.
So what Product & percentages to Distiller Water do you use?
canât remember exactly⌠i used the most basic stuff from the car parts dealer. probably around 10% antifreeze (but this should depend on your climate, if you go to -20°c because you live in canada use the same dilution you would for your car)
Hereâs some great information on the conductivity of antifreeze in a laser tube.
There are so many articles on the net giving very good reasons for not using anti-freeze as well as not using deionised water, and actually the cooling water is in the âinnerâ glass tube, not the outer.
I am also in the UK. I still use the traditional reservoir and pump as the cooling system and my laser is located outside in a shed. For winter and generally in colder weather I use a 50W fish tank heater to stop the reservoir freezing. I donât leave my pump running but I to leave a 60W tube heater on which is laid in the back of the machine under the tube position.
I use Distilled water which I buy from apcpure through ebay, about ÂŁ25 for 25L and free delivery. There are many suppliers to order from on-line. I do not use any additives and have never had a problem with bloom of algae. My reservoir does have a lid on it which helps to keep the water clean and helps stop evaporation.
I mentioned having the fish tank heater on in cooler weather as well. The reason is I find a cold tube of below say 15C doesnât perform as well and my power settings need to be increased to compensate. Keeping my tube above 15C is so much better.
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Rather than using ethylene glycol (conventional antifreeze), glycerine can be used.
When glycerin is diluted 50% by volume with water, the freezing temperature is about -30 ° C.
$35 for a gallon of glycerin yielding 3 gallons of coolant. (Oh and it makes for AMAZING fog juice if you own a fog machine)
At ordinary temperatures, the conductivity of glycerol (on its own) is 5x10 ➠⸠(that is 0.00000005) reciprocal ohms (also known as a mho; also known as siemens).
JONES, H. C., e t al., Carnegie Inst. Wash. Pub., No. 180, 153- 178. 179-199 (1913)
@Hank , thanks for the LaserGods link you provided with the conductivity info. With that, I used the Resistivity vs. Conductivity graphic there and overlayed the following additives discussed in that article (and added glycerol electrical conductivity when mixed with distilled water).
Note the values provided assume distilled water is used as the base solvent (while the plain tap water range is provided for reference. If combined with tap water, these same additives would scale further up, having MORE conductivity than illustrated here).
Awesome graph Jeff.
So having a more than 50% Distilled water diluted solution (Glycerin or RV antifreeze) is looking promising. Sebastien said he was using about 90/10 solution.
I understand everyone using an aquarium heater, but that doesnât solve the question with no power for a week. A fish tank heater doesnât help those with an S&A chiller either.
Where in the UK are you? I donât remember having a power cut for more than a couple of hours here for many years.
Im not in the UK, Im in TX.
Oh OK, donât know why I thought you were in the UK. I had a couple of hours on the forum tonight so must have picked that up from another post. My apologies.
London, Tx. ? 
haha. no, We have an Athens and Paris too.
Political mess, but long story short, too much confidence was put into solar power, and it couldnât handle the demand. Took a week to recover from lack of winterizing.
Frank, how did u determine the 50% dilution temp
of -22°F (-30°C) of Glycerine?
Wondering what temp that would be at 75% distilled water to 25% glycerine mix