thread ... the diode ones are a bit shit, visible light so can't do we through stuff
and not powerful enough to cut much, but ok at etching.

The "40w" CO2 lasers are known as k40s. They're cheapo versions of proper laser cutters, and will arrive in a condition somewhere between deadly and 'will work OK but a few simple improvements will get it running well'. And there's no way of telling which yours will be.

I've found an AliExpress vendor who has UK stock, so it's wick and avoids import duty. And it has an ammeter rather than digital % power display (which is good because 100 on the display is likely to mean 150% which will kill your laser tube).
permalink those pesky 007 agents bothering you?
what are you cutting? i wouldn't mind one that cuts fabric.. i'm guessing that will be much weaker..
permalink Don't really know. Wood, probably.
And perspex.
permalink 50mm Corten Steel?
?
permalink It'll do 3mm of ply.
Anyway, I've ordered one.
permalink How much?
I too have a burning (sorry) desire for one, albeit with no real need or justification of any sort.
permalink About £250 from Ali express with a UK warehouse.
I expect to spend another £100 getting it working properly