The reason you might think I know nothing about lasers is because of my trying to purchase from eBay. The reason is I trust eBay gaurentee and I can't afford to much so eBay is what I am looking for. I'm not some kid trying to annoy neighbors with too much time on my hands.
Asking if a class-IV laser is a good idea for a newbie gave it away. No, it's not a good idea. See below.
Your asking "do I need goggles" was a clue as well. Yes, you need goggles. Class IV lasers are unforgiving, far more so than their IIIb counterparts.
A class IV laser is a terrible first laser, all the more so if you apparently don't know that you need glasses for it. No way I'd recommend or build one of these for somebody who doesn't know what they're dealing with. You're better off getting 100mW or thereabouts, so that if (when) you get a reflection in the eye, you
might not suffer permanent damage. Once you get into class IV there are no do-overs; accidental reflections, even from clear glass, are as dangerous as a IIIb direct hit. A reflection from a mirror will almost certainly do permanent damage.
The 3.5 watt lasers are flat-out scary. Stay away from those until you're more experienced and familiar with what can go wrong, how things go wrong, and that sort of thing. If the spot size on a laser like that (e.g. close to the aperture) is 15mm^3, then that comes to a power density of ~233kW (kilowatts) per square meter, roughly 170 times brighter than the sun. "One strike and you're blind", pretty much.
I've been hit with 140mW of 450nm (blue), right in the eye, a single brief flash due to reflecting off a mirrored object in the background that I didn't notice. You would be surprised at just how easy it is to get hit like that, and when it happens it's scary. The laser left a bleached spot in my vision that persisted for more than a week. It eventually faded away and a subsequent eye exam showed no apparent damage. I got lucky. But clearly the laser did some short-term damage, because you aren't supposed to have a persistent after-image like that. I'm really, really glad that laser was "only" 140mW and not 1.4 watts.
Sorry if you're feeling cranky but if that's how you respond to our concerns then lasers might not be for you. Consider taking a different attitude towards safety and whatnot, because high-power laser damage will be with you for life.
I am not stupid. I know of the risks and have watched many videos about safety and many reports of those jailed for shooting lasers at planes.
Too defensive. It's good that you know about the dangers of lasing vehicles/aircraft. There are other hazards, see my story about that above.
I think I'll take the gamble, I can ship it back if it sucks that much. Besides it looks cool.
Good luck. Even if you do get a return address, you're shipping to China. You'll pay a significant fraction of the purchase price just to get it back there, unless the seller agrees to cover it. I don't think they generally do.
I don't need to hear how it's crap, but if you have suggestions let me know.
Buy something else, it's crap. You don't need to hear that but I'm sure we'll all get to read the thread you post when it dies, amirite?
The only answer you'll get there is "it's crap", by telling you this now we're saving everybody some spam.
I don't care about duty cycle unless it is less than 30 seconds. Like a 60 on 60 off is fine.
You'll care. 60 on 60 off would be an absurdly annoying duty cycle. I've tried it with my C6's just to see and no thanks, get a bigger heatsink/host because yours is not up to the job. Better, get a heatsinking (custom) host. These have no separate heatsink; instead, the entire mass of the host is available for heatsinking and transferring the heat to the air. Custom hosts are generally a lot more durable as well, and the price is lower than you might think.
My own opinion on that of course but if you want to do any photography with your beams you'll want long on-times. It can be a PITA to get things set up just right, and running up against the duty cycle all the time is just irritating.
I'm sorry if I offended someone. People have the tendency to believe that just because a person is new to a forum, that their new to that hobby.
You didn't offend anyone, you caused concern due to not taking advice that was meant to direct your attention to safety. If we need to be blunt in order to get the point across then we will. You can get over any butthurt caused from that, you can't get your retinas back after you torch them because you thought shining it at a mirror or waving it around would be cool.
eta: Here is what we'd like you to avoid –
Hit in eye with 1000mW blue laser. Yes, that injury is real and the damage is for life. How would you like some of that?
eta #2: If you just like that host style, there are machinists here who can probably duplicate it, one of whom can even do the anodizing in different colors. Such a duplicate would be superior to the chinese laser host in every way - durability, heatsinking, general quality of the metal, threads, and whatnot. If the laser dies, replacing parts is much easier than with chinese lasers.
op: