LaserUser.com Forum (formerly RDWorksLab)

I recently looked at my semi-transparent silicon tubing that runs from my S&A CW5000 chiller to my glass tube CO2 laser. To my surprise, both the inlet and outlet tubes had a rather brilliant blue-green color cast to them. The color didn’t seem correct to be algae growth but I wondered if I maybe had an algae variety I had never seen before now. Therefore, I proceeded with a plan to put a cup of bleach in the water reservoir, let it circulate through the system for an hour or two and then do multiple complete changes of the water to remove any remaining algae and bleach out of the system.

The bleach solution was not effective to remove the blue-green from inside the tubing. My next step was to disconnect the tubing running between the chiller and the laser in order to look inside the tubing. As you can see from the pictures this does not appear to be algae. It is a strange coating.
To me, it looks similar to copper corrosion. It removes easily if you run a bottle brush or similar down the tubing.

Has anyone experienced something similar? If so, what was it and how did you stop it? I have never used anything but fresh distilled water in my system from the first day I have owned it. This is the first time I have experienced this. I am wondering if it is copper corrosion residue coming from something internal to my CW5000 chiller. I don’t think anything else in the laser cooling system has copper.

Thanks!

'Silicon' isn't always just pure silicon in particular if the origin was lowest budget sourced. Likely if you are running distilled or worse deionized water in your system the water is likely stripping things from the Tube, Pump or Container and putting them in suspension then coating other bits.

The basics of this is water doesn't like to stay 'pure' and will tend toward a slightly mineralised state by getting what it can from anywhere.

Hi Doug,

We had the same thing happen to our machine. We had a service guy out working on our CNC and he was looking at the laser cutter as he sells them as well not the eBay types but his own version and was interested what was in them. He said to change the tubing over to good stuff from a hardware of aquarium store, as the stuff they put in is not smooth on the inside and hold all the bits that flow through the water and give algae a place to grow. So we changed ours out all of it, it was pain of job, but it was worth it.

We also use water that goes through a reverse osmosis filter and run a pond algae killer in the water. has been going strong now for 3 years and we haven't needed to change the water once, just top up a bit.

Matt.