@sirus20x6, I’m assuming you want this for laser drilling of via. I think you will run into a couple of problems with the GF in this application.
First, @jkopel is correct, you will most likely have issues going through the copper layer with a 45W laser.
Secondly, you will also probably have an issue with accuracy. While the optics on the GF are great, they do not seem to be designed for micron scale alignment. For high density circuits, you need to be able to align to very small targets (usually <100um) to insure you are drilling in the correct locations.
I would recommend an Othermill for quick PCB prototyping. Copper is a great mirror at 10600nm. For cutting it, you want a YAG, fiber, diode, or other laser.
That said, you can (I’m told) get some fantastic, super detailed etching by putting a resist on the material, engraving it off with the laser, then chemical engraving. That doesn’t get you holes though.
Does this mean you could create pcb traces on a copper clad board by putting down a resist then engraving away the negative space with the laser to expose the copper then etching the away the copper with ferric chloride? Could you do a different (but aligned) pattern for the bottom side for double sided boards? What material would you use for the resist? Would the etched away portions with exposed copper act as a mirror? Could the “mirror” damage the laser by reflecting the beam back into the emitter? Any thoughts on using the laser for solder stencils (material, accuracy, etc)?
You could probably use Kapton Tape as a resist. I’ve put that through some pretty nasty chemicals as part of an electroless nickle platting line and it didn’t deteriorate at all. I’ve never used it with ferric chloride though, so you might want to do a test piece. As for double sided, I would imagine it should work.
When doing very short pulses the normal wattage rating doesnt mean much. if the laser is on for a millionth of a second it can far exceed that constant rating of 45watts but will then need some time to cool down before the next pulse.
Normally double sided boards would be impossible on a standard laser but the glow forge has a camera for alignment so hopefully if you print the right fiducial (alignment) marks on both sides of the material this will be possible.
The laser should be fine for making solder stencils, loads of people have done it before even on cheap Chinese lasers there is no reason to believe the glowforge won’t have the same levels of accuracy