Bubbles in the cooling system? More specifically, what is the effect of bubbles attached to the glass inside the laser tube?
Note: large air bubbles pass right through the system without a problem. It is only the smaller ones, attached to the inner surfaces of the tube's cooling chamber, that I am concerned about.
What I am seeing (and hopefully attributing to the bubbles) is a gradual loss of power over a longish engraving job. The jobs start out fine, but after 15 minutes or so, begin to loose power. Waiting a sufficient amount of time and starting over produces similar results. BTW - the water NEVER gets warm, let along hot. Since the bubbles are lining the tube, is that allowing the tube to be hot and loose power while the water passes right through without being affected?
Along with everyone's speculation as to the effect, I am open to suggestions for eliminating them. I believe they are caused by organic growth in the water that is contaminating the inner surface of the tube's cooling jacket. I now have an algaecide but believe I need to "clean" the tube first. I did add some bleach this afternoon and am letting it circulate. We'll see what happens.
I have a new tube coming, but really want to figure this out before I put it in. Don't want to potentially damage yet another tube.
All suggestions and comments welcome.