After flailing for a few days with what I thought was a bad power supply or tube it dawned on me that I had never used distilled water (I am always tearing it apart and how conductive can the water be anyway?) and I knew that I had some algae in the tank.
I knew better from listening to others but seriously arching through the glass jacket through the water to gnd in the tank? You better believe it, I have now proven it, to my satisfaction that is. I should have known better because I worked with someone that was blowing supplies every month and it turned out to be CAR antifreeze (that’s definitely a no-no).
The symptoms was an intermittent screeching noise when the laser was in operation. It did not do it continuously and it did not do it every time.
I thought it was coming from the LPS and finally was about to conclude that it was a failing winding inside the fly-back transformer. What bothered me was I could see no evidence of an arc even in a dark room.
What I did notice was the flux beam shifting and changing shape at the anode end only when it screeched!
So I cleaned the system put in distilled water (3 Gal) and RV antifreeze (1/2 gal), powered it up and from then on no screeeeeeching just smooooth wood smoking power.
I wonder how many good laser power supplies and tubes have been replaced or fry’d do to this problem.
By the way these supplies are not designed to withstand many arcs…is this why they are popping?
I wonder how much leakage current there is through the water bucket?
Lesson learned “take your own advice”, clean the tank often and use distilled water.
Nice to see more users find this out, i have been yapping about the water for long time and got a lot of shit for it
And btw, RV-antifreeze has about 400x more conductivity than distilled water, increases the viscosity and lowers the thermal pickup.
It´s not super dangerous, but not good either
I would say with confidence that bad water and overpowering is the two top factors why a tube or power supply gives up.
I received a new tube last week and it was screeching so I returned it, I’ll swap out my water now as I have been using softened water. My last tube didn’t do it but it’s worth swapping over now I read this.
@HP_Persson Here is some actual data. I don’t know why I never thought of measuring this before. I wish I had measured the water before emptying it.
I used a HM Digital COM 100.
The temp was about 60F
Distilled water = 2.6 uS
Distilled/RV mix:6:1 = 142 uS
RV antifreeze = 414 uS
Don’s tap = 370 uS
Prestone (ethelene glycol) = 633 uS
There is the 400:1 that @HP_Persson refers to.
I wonder what is acceptable. I will probably replace mine.
I think this is something we all should monitor
…thanks!
Yeah, looks pretty much the same as i found out in my tests. Bottled drinking water was better than RV antifreeze in my tests. Not sure if RV antifreeze was at a level it really damaged anything though.
I did mention in a FB group it would be better to cool the laser with camel urine than RV antifreeze (i was joking), so we actually called the local zoo, got some ph and other values to mimic camel urine in a fluid
Thermal pickup was better, but it was conductive as frig and my room smelled like hot yoga pants for hours
If you have a camera to shoot slow motion, check out the beam while using RV antifreeze, it will deviate with that too, just quicker and less jumping, while plain distilled doesn´t make it move much at all.
Theoretically this jumping and deflection causes the recombination of gasses to slow down, if it does it enough so we can see it as a tube failure or not, i have no clue about.
Nice findings! there should be more testing and confirmations of tests like this to find the best cooling option, to spare power supplys and laser tubes for us users
That’s interesting. I’ve just been using rain water from my laundry sink since I got my K40. Although, admittedly I don’t use my laser as much as most of you guys (usually only for a couple of minute jobs or max of 1 hour job).
@donkjr i think you’re right. I noticed this screeching too and found algae in my tank. Just replaced my tube and water. No screeching but I’m definitely going to change the water for distilled water.
I dont believe antifreeze is the only answer. First off, I’ve only had my laser a 8 days. But after researching it, i found as stated above propylene glycol not ethylene glycol is the proper antifreeze. Further digging indicated that growth of organisms and corrosion prevention are the only issue to be addressed. My solution is to use Redline water wetter.
Its intended to be used in racing engines with water only no antifreeze so its very good at corrosion prevention and heat conductivity. I see no change from just distilled water, but time will tell.
Why? because I’ve spent 25 years winterizing boats with proplyene glcol and if left for more than a year you see growth and I believe fermantation as it will smell of alcohol.This effect could be from the plastic tubing used or other causes but rather than guess I avoid it in this application.This is with -50 deg antifreeze which IRC is 40% propylene glycol. Boats were drained of water and straight PG antifreeze fills the entire water system.
@Steven_Whitecoff the problem is not corrosion prevention, its conductivity.
Apparently the growth of organisms in water clearly increases its conductivity.
The point we are making is that RV antifreeze is substantially more conductive than distilled water (algae or not), see the measurements above.
None of the applications you sited above need to insulate 20,000 from gnd. so that not an apples to apples comparison.
Why use any any antifreeze at all? Some want to prevent freezing and algae. These measurements suggest that antifreeze protection results in a substantial increase in conductivity over distilled water. Yes RV is better than Auto but are either a good idea?
I also have read that RV antifreeze is better than standard car antifreeze and that makes sense as it is less conductive.
We don’t know the threshold for conductivity while corrosion resistance is a minor factor as its a glass tube.
It seems 400x more prudent to just use distilled water and keep it clean.
If we add anything to the water we should measure the conductivity i.e. alcohol.
I am going to let some tap water sit and monitor its conductivity over time as it grows algae.
I wrote a article about coolants a while back, i´ll add the infographics i made below, maybe can give some ideas to someone.
This is after testing alot of different coolants and their properties (conductivity, viscosity, thermal properties and bio-growth)
The corrosion part isnt a big issue for us though, but it may affect the anode and/or metal parts in the pump/loop.
Hard to find in small quantities though so you’ll have leftovers.