Replacing my laser tube

I just replaced my laser bulb in my 60 watt omnitech co2 laser. I have a question about the tube itself. Hopefully someone here can help. When the laser fires the outlet side of the bulb the laser beam bounces around in a circular pattern. I never noticed this on the old tube is this normal? you can see this on youtube - YouTube

Thanks in advance

The video is marked ‘private’ :frowning:

Might try a short pulse tape on m1 to see the output of the beam.


Not to sound like a dummy but what is a pulse tape
Thanks Jack

I use blue painters tape. You pulse the laser on low power to mark the tape. You do this to align the mirrors but you can also tell how well the laser is working by the pattern. You don’t put it on the mirror, but the port that is in front of the mirror.

I did that after replacing the bulb to make sure that it was aligned properly thank you I also made the video public sorry for the mess up

It still says private

I’m new so I don’t know answers. But from what I’ve seen the consensus is one of two things:

  1. tube is bad
  2. low-grade cooling water is causing the arcing so get some deionized water and change it out
    FIXED - Laser Tube Arcing and Power Loss - YouTube

I don’t know if either of these is actually fact but that’s what I have been seeing others say. You might call a laser tube supplier such as LightObject and ask them (they are likely to know what the actual cause and solution is).

I also don’t know what term should be used to describe the phenomenon, but it’s usually referred to as “arcing” in discussions.

Thank you. When I replaced my laser tube I drained the old distilled water and replaced it with new. I also read that if the gasses in the tube are low the arching could occur

Thank you for your input. I will call them and post their suggestion

The voltage from the lps can go real high if the tube doesn’t ionize, so if the tube fails, you could see arching.

Distilled water has a high dielectric and works well for a coolant. Deionzied is best, but exposure to air will change it back to distilled water very fast.

Is the ‘laser’ and when the gas breaks down to it’s constituents, it fails to lase. I wouldn’t call it ‘low’… This can happen over time, so when you purchase a new tube, don’t get one made a few years ago and has sat on a shelf.

Ensure the coolant return from the tube is facing up or the correct orientation to ensure bubbles will naturally ‘flow’ out. I have mine facing up.

Good luck


They told me that the arching was normal. I still find that odd as the arching on my machine is becoming more intense.

This tube is less than 3 weeks old and has maybe 1 hr of use . Would you return it?

I’ve only had a co2 laser for a year, but I’ve been pretty involved with them and mine is pretty modified.

I’ve never seen a properly operating one do that. The field is DC excited, not DC arced.

I think if you hunt around for the arcing, it’s surprisingly common and internal arcing seems to be present in a failed tube.

I would try and have them replace it…

Do you have a mA meter? If so, can you control it… don’t know what a ‘right’ answer is about this. Just always been curious.

You could send the video link to someone like Cloudray via email and ask them if they think that is your problem … just a thought.

Maybe they can sell you a tube… :crazy_face:

Good luck


Just FYI, but first a disclaimer. I’m still new so my level of certainty on any of this is pretty low, but having said that…

I called and asked about it too because my tube also has that curved path of the pink beam at the “exit” end of the tube near the metal ring area. It’s a “smooth” curve, i.e. it doesn’t jump around much, makes no noise and is constrained to that single spot in the path inside the tube. Also, I have a Mahoney power gauge and the tube output power matches what I would expect based on the PWM percentage input, and a mode burn also shows about what I would expect with normal tube function. With that in mind, what LightObject told me was that this is not uncommon and indeed deemed it “normal” and would be suspect only if I had output problems.

There’s always the possibility that in the process of describing what’s going on, there could be a communication / understanding gap anywhere in the people chain, so keep that in mind. This is simply one data point so far.

So for what that’s worth, there ya go.

I have distilled water in my cooling system at the moment and someday soon I will try replacing it with deionized water to see if anything changes just because, but at the moment I intend to just use my machine so I can start to learn more about the cutting process rather than all these machine function items I’ve had to concentrate on lately.

Fortunately my tube is warranted for another couple years and I’m sure I’ll have much more certainty of the health of things soon. But for now, since I apparently have acceptable beam performance, I’m just gonna trudge ahead and keep an eye (and ear) on things as I go.

Sounds like you have a good handle on things.

If this is the case, I’d follow their instructions. If there is damage, it will likely show up before two years…

Can’t beat that kind of deal…

What is this to you? A perfect beam?

Keep in mind that not all tubes that die do so overnight. Most often they degrade slowly.

I’d like to see what your beam looks like coming out of the tube, mirror 1 (m1). Most of us like looking at this stuff anyway :crazy_face:

I would think there would be no circumstance an internal arc would be acceptable, but it’s their business and hopefully they should know.

That ‘arc’ is power that isn’t making it to the laser. Mine just glows pink…

Part of your mA meter reading is that ‘arc’ current.

I can pretty much bet, you won’t see any change. This isn’t a ‘worthwhile’ difference in distilled water and deionized. The bad part about deionized, it quickly changes back to distilled water if exposed to air. Not to mention it’s expensive and can be corrosive to some type of metals.

When I was a kid in S. California along the coast the power company sent trucks out to the 100kV+ lines to wash off the salt accumulation, they would just ‘hose’ them off. They used distilled water, not deionized.

Good luck


Jack that is exactly what I intend to do. Could you tell me what MFG Tube that you currently use?
Thank you

How can I send you a video of that?

Video of what? I saw the one you posted.

Clueless… It came with my OMTech 5030 China blue machine.

I haven’t been able to find any kind of ‘mark’ for a manufacturer. This is the only label with any information. The other label marks the output end…

Kind of like telling me which end the bullet comes out, pretty useless.


Same type of video other than the arching is becoming more intense
It is a MCWlaser brand

Arching is becoming more intense