Basic laser questions...

[WilliamD]

I'm looking to build a 50 watt laser table for cutting cloth material and 1/8" hardboard for scrapbooking. I have no problem building the table and x-y movements, based on having build my CNC router. But the laser part is new. I've followed a couple threads, but a few things still evade me.

First, the laser tube. I gather that there are two kinds. A "sealed" tube, that doesn't require an additional gas setup, and a "freeflow" gas setup, which would require an appropriate gas setup. Is this correct. Is the "sealed" better and less hassle? Is the gas that hard to find for the "freeflow" kind?

And second, the power supply. I have some limited knowledge about DC power supplies. I construced a few of my own from microwave transformers, so I definetly get the basics of an unregulated DC supply. But the laser transformers seem to be in the 20 to 30K volt range. That's some serious voltage! Is it basically a DC supply that's geared for high voltage and low current? What makes the powersupply's so expensive. Even more than the tube's in most situations.

And last, is all I basically need the tube and power supply. I know I need to focus the beem through some mirrors and lenses. I guess I'll have to find those on ebay or some sort of supplier. I've looked through www.emissiontechnologies.com and like his setup. I like CNCAdmin's even more. Definetly like the cost. But I was intrigued by their plans to build your own laser tube. The biggest thing perplexing me is the power supply. With how cheap the tubes are, I would definetly just buy the tube. But the power supplies are outrageous!

Any insight would be greatly appreciated. After I get this laser going, I'll have a CNC mill, router, plasma cutter and working on the lathe. I'm hoping to open my own shop someday and just do as much work as I can. That will always be the dream though.

[CJL5585]

Tried to buy a new capacitor rated at 30,000 Volts lately? Probably will cost you a couple of hundred dollar bills.

The high voltage supplies require extremely high voltage parts. This is one reason for the hight price of the supplies. High voltage will ARC several inches and destroy ANY part used that does not have the proper voltage rating. One must also have the proper spacing between the various components due to the fact that the arc distance will vary according to the relative humidity. Also, these supplies are VERY DANGEROUS, especially for novice builders.

Also, you need to learn about laser safety (especially going blind in an instant) before you start building a unit. Laser light is reflected off almost every material known to man even black foundry sand, and most true lasers emit light in frequencies that are invisible to the human eye. Any material can act like a mirror to the laser beam frequencies, so one will need laser safety glasses and an infrared or ultraviolet viewer in order to see most laser outputs. Pulsed lasers Class 3 and Class 4 are the most dangerous and can destroy vision in a millisecond.

A 50 watt laser is a very dangerous weapon.

[WilliamD]

When disassembling microwaves, I noticed that the cap in there was 2000v. Could I put a bunch of those in series to add up to the 30K volts? I know that it's dangerous, and I would take every precaution. That's why I'm doing all the research now before the build. Anyone know about that laser tube and being sealed?