LaserUser.com Forum (formerly RDWorksLab)

I have been using a Chinese K40 for about two years now cooling it with tap water ina CW3000. The water is changed every three months regardless of usage.
Now the question.

I have just finished building a 100 Watt 1200 x 600mm machine and want to do the cooling correctly. The design is a 40 litre header going to the tube out via a flow meter and temperature gauge into a radiator which has 3 fans forcing air through the radiator into a second radiator again with forced air through it and back into the reservoir.
My question is.... Should I use Distilled Water? which 50% of the advice seems to be or Should I use De-Ionised water? which is the other 50%.

Does it mater, is one better than the other ?

Totally confused

De-ionized / distilled is what you want to use. No mineral or chemical contamination. In fact, if you are going to reuse any mechanical parts from the old setup, they need a through cleansing with white vinegar. It doesn't take long, but the vinegar will remove most if not all of what your tap water has left behind. Once filled with distilled, then isn't just a matter of keeping the system as close to sealed as possible, and topping it off once a year. I loose about a gallon every six months in my current set up, but I have a spot I can't seal as well as I like. At .99 per gallon USD, I'm really concerned about the loss... LOL

I'd be interested in hearing more about your build, I'm considering one myself.

As someone who plays with removing Scale from Espresso machines Citric Acid is a better thing rather than Vinegar for Calcium in particular. It also doesn't pong Should be available near the Herbs and Spices in your local supermarkets or in bulk online.

With Water Chemistry there are some similar sounding terms that are a trap. Also bear in mind Water is the home for Snake Oil sellers and BS abounds.

De-Mineralised is not generally without minerals it is mineral reduced. This is what tends to come out of Domestic and some Bulk Commercial Reverse Osmosis plants. In Indurtry depending on the need this is step one toward getting pure water and not the end point. Typically 20-50PPM leftover.

De-Ionised is generally secondary treated De-Min fed through Resin Exchange and other filter media to try and further remove more of that leftover lot typically you will be down around 5PPM

Distilled and even double Distilled will get you down to nil but in practice sub 1PPM is achievable without going to radical extremes.

When I had a real job Kodak was one of my big customers and I was selling them pumps for their purification and it they were measuring in Part per Billion. Part of a major refit was their water was destroying Marine Bronze parts in the pumps so we had some wacky Bronze parts made for big$.

So Distilled is best but it comes with a pricetag.

OK, sold.... I will go with Distilled but will definitely need to save a few pennies as it does come with a price tag in the UK. You are right about all the BS etc, it seems that Deionized would be a reasonable second choice, but after spending months building the beast I am not going to risk spoiling or damaging it for a few pounds.

Thanks for a clear definition of the differences.

Citric acid. All I see is powder. I'm assuming you mix it up with water. Tap good enough for cleaning, or does it need to be mixed with distilled as well?

If you use tap water it will just lose a bit of it's sting as a cleaning agent. Generally it gets done with water out of a Medical R/O I have which on this local supply sits at about 12PPM (where it used to be used I was using 800-1000PPM bore water YUCK! it would get to about 30PPM) . For heavy Calcification I actually Cook the parts in a pot of Citric but that isn't ideal for Laser use

Just wondering if the water I throw away after using my tumble drier is a contender? It's condensed water vapour, so in that sense it's distilled water, but I don't know if it's picking up contaminants on the way to the plastic tray.

Any thoughts?

Don't see many of those on this side of the pond except in travel trailers and some of the larger boats. Maybe someone on here can speak to that, but I would suspect it would have a fair amount of fabric / lint contamination in it. All i could say is collect some and let it sit for a few days. If you see any kind of clouding and sediment then there's your answer. Maybe run it through a coffee filter?

Here is a great read on cooling and additives

https://lasergods.com/laser-water-coolants-additives/

As always, great info, but I still come back the second sentence of the overview.

The theoretical, as well as practical, implementations and observations vary from person to person and source to source.

In theory I should have a dead laser. In practicality, I ran 100% RV antifreeze last winter for a little over four months. My only side effect was the silicone tubing took on a bit of a pink tint. The pieces of poly I added were not effected at all.