Do this before you replace your Co2 Laser Tube

The only reason you get that window "smoked" is because there are fumes in that area and the beam exiting that window is "cooking" the fumes onto the anti reflective coating. The mirror you speak of is on the internal suface of that exit window and is still working perfectly. However the 5% light that escapes through the partial mirror to create your 90 watt beam is being compromised in two ways. 1) It 's intensity profile is being distorted away from Gaussian and is the key reason for apparent power loss. 2) there will be 2 or 3 watts watts absorbed by the debris film and if you let it get too bad it will heat the outside face of the window and cause an obvious star crack. The manual specifically says DO NOT CLEAN THIS WINDOW . I have been in your position and have carefully remove a slight haze with alcohol and VERY gentle use of a cotton bud. There is always a film left by alcohol that MUST be cleaned off with a gentle lens tisue wipe or that residue will again cook on. For fumes to aggregate in such an eclosed area as the end of your tube must say something about the fume extraction effiiciency within you machine cabinet. There should be ZERO fumes in this area and I can see from the crud on the outside of the tube that there are fumes in this area. If you cannot identify the problem, then position a small low pressure air jet across the end of the tube to make sure that output window stays fume-free.

You the man, saved me some cash mate and stress. Worked like a charm

Great video....Good job.

Thanks Jay

It’s worth mentioning that it’s a lens rather than a mirror (although with an internal semi-mirrored surface), and pretty fragile. From the Reci model W instruction manual: 3.7 Notices The surface of beam output lens cannot be scrubbed with any tools such as cotton balls, otherwise the power will be serious affected. Here are several methods for cleaning. (1) When the lens is contaminated, do not use the laser tube; (2) Blow the lens surface obliquely with balloon; (3) If the above no effect, user needs to remove the lens and use a cotton ball with a little alcohol to rotate the lens. (4) No need too much alcohol, but the glue layer of the adhesive lens cannot be touched in case of gas inside escaping. (5) The laser cannot be used till alcohol evaporating. (6) Do not scrub the lens with acetone. The best way to protect the lens is keeping the environment clean. (7) When testing the beam on plexiglass, please keep it 300mm from the mirror. How you want to interpret that is up to you, but if you’re going to scrap the tube anyway it’s worth a try.

Does this also work on glowforge machines? Thank you!

Think's

Do you have a video how to flush gunk out of the tube? The stupido's that put in my new tube did not flush the chiller and now all that crap is inside the tube 😤

I can't get denatured alcohol in my state anymore. Could a guy use 99% Isopropel alcohol instead?

Mine has a damage spot, maybe thats the reason i get not a thin line in 3 of 4 corners. Only in the corner where the laserbeam has the longest way in the right front side i get good engraving results. So why cant u replace that lense? I dont wanna spend 500$ for a new tube. I dont even used it very much, it would be very annoying

can you change that lens?

How do you know you have a bad laser tube? Do all laser tubes have that hidden mirror?