Hi, I am new to laser but have built cnc routers and 3d printers

Hi, I am new to laser but have built cnc routers and 3d printers over the years also a diode driven laser from the great plans by 3DPBurner. I have learnt a great deal from this excellent resource and have ordered the Cohesion 3d mini laser bundle to do the upgrade that seems to be the best to make the k40 a better machine, my question is what do you guys do about the bubbles that collect in the tube? is there an easy fix, is it ok to rotate the tube so that the outlet is at the top. Thanks for your patience with a newbie

Here is what I have heard on forums. I tip my machine to remove bubbles cause I do not want to realign it. Plan to rotate the tube first time alignment is necessary.

  1. Keep drain side under water
  2. Put tank above level of machine
  3. Use a couple of drops of dish detergent to reduce surface tension
  4. Rotate tube (this may cause arching if anode gets to close to case). Optics will likely need realignment.

I have only implemented #1.

The bubbles will work themselves out over time - no worries

@greg_greene ​ huh! mine stays unless I tip the machine. Not good to run with bubbles.

My pump and reservoir are at the same level as the tube is, so I get full pressure, that seems to clear the bubbles quickly. Is your pump below the machine on the floor?

you can also use something like that to push the buble out (with a slight tilt of the all K40) :

@greg_greene my pump is below, will have to try that?

If you get your pump a little higher - the bubbles will naturally rise to that level instead of the tube

Ah ok, so not just me being new then, I do have the pump under the cutter so I will lift it up and give that a try. I did try to shift the bubbles with an air pump, that did work initially but they returned the next time I fired it up, I will also try the trick of lowering the surface tension. Thanks guys at least I don’t feel so bad about it now :slight_smile:

there is a product at the speed shops called water wetter that the hot rod guys use to reduce cavitation around the water pump impeller and keep bubbles from forming - haven’t used it in this situation though

Yes I bought some flow improver to mix with water to make acrylic paint flow better in airbrushes, it was expensive I remember and I suspect it was just detergent as Don said, so I’ll give that a go, as well as lift the pump. Thanks again.

Just make sure whatever u use is not conductive :blush:

Hi Don is that why distilled water is best and not deionised?

@Richard_Treherne yup!

Yup Again !

Ok :slight_smile:

The last tube that I bought actually had the water outlet rotated so that it was at the top when the tube electrode was pointing up so the bubbles rose to the top and had an exit.

@Mike_Mauter and problems with anode to close to case?

No problems so far. The water outlet is actually formed/cast/blown into the glass where it is at the top of the tube when the anode is pointing up. Other tubes that I have had had the outlet on the side or bottom when the anode is pointing up.