need to understand types of laser tubes

[Jacqui Marlin]

I am trying to evaluate whether I will be able to purchase a small laser cutter and one big question I have is about the tube. I am hearing negative remarks about glass, but why are they bad? Or are they? And other tubes - are they metal? And why are they better? Glass tubes are water cooled but it seems some are air cooled? And most important - I am seeing a wide range of tube prices and life expectancies. I am curious whether tubes are interchangable between brands? Are all the Chinese laser tubes the same for the size machine? Lots of questions here but I need to evaluate many factors before I make a decision.
Thanks for any input you all can give me.
Jacqui, Goddess of Chaos, GSOLFOT

[Dave Jones]

Old style laser tubes are water cooled glass tubes. These are used by most Chinese lasers. They have a tendency to drop power gradually over time. Typical lifetime of tubes is around 600 hours of use.

Modern laser "tubes" are metal blocks with a very thin chamber inside that creates the beam. They are typically air cooled with fins on them. Typical life of the tube is around 30,000 hours of use, thought the RF circuits in them do often blow out every few thousand hours and need to be repaired.

[Dean Carpenter]

My advvice: stay clear of the Chinese glass tubes. I have tested them extensively and found them to be: unreliable, unstable, power-hungry and somewhat potentially dangerous during maintenance.

You are spoilt for choice in the USA with high-quality, reasonably low cost metal alternatives so go with a home-grown product and have peace of mind.

the glass tubes are a flase economy.

Dean