Thanks for the reminder about Gemini… I decided to try it out and have been enjoying the process so far. We’ll see how it goes!

Definitely neat, particularly in some sort of disaster scenario where you’re building stuff out of scrap. I bet you could replace those aluminum “offset printing plates” with sheet aluminum from cars that are built with it. (Mostly fairly pricey ones, but I’m thinking of scenarios where that’s no longer an issue.)

In more prosaic situations though, modern PV panels can produce more wattage even in marginal latitudes. So I’d think of wind turbines as something to supplement a system and maybe lighten the load on batteries during overnight hours, rather than a primary power source.

In the marine world, small 12V wind turbines used to be a pretty common sight on the back of sailboats… which is really about the best possible situation for one. (Sailboats tend to be located in places that have brisk winds.) But in the last 10 years most people have stopped bothering to install them, and are making more and more flat surfaces out of PV panels instead. You just get more bang for the buck buying more PV panels and batteries than you do buying a wind turbine setup.

But for scenarios where it makes sense, I love seeing designs that don’t assume you have the entire McMaster-Carr catalog at your disposal.

Looks great! I’ve looked at that box design and wasn’t sure about the “grip rails” that it has on the lid, or the rails on the box; they seem kinda fragile-looking to me, at least made out of wood. How did you improve the lid design? And does it feel solid when made out of acrylic?

I think big question is whether you want to DIY something or if you want a more commercial, ready to use out-of-the-box solution.

The open-frame Cartesian kits (which are basically the same hardware you’d use for a CNC router) are the cheapest for their bed size, and you can make them quite large. I’ve seen some Youtube people with what look like 4ft x 6ft machines. But the common designs seem to just leave the CO2 laser tube just sitting exposed… no case or anything. And that strikes me as not safe unless you have a dedicated workshop you can absolutely close off from any wandering people / pets / whatever. And you’d need laser safety goggles, obviously.

The K40s seem to be a good value for the money but there are a lot of horror stories around of people getting units that need a lot of work before they were able to run anything. At least, that seemed like the case a few years ago. If you don’t want to mess with that, there are US-based companies that seem to be buying the components from China and assembling them (or at least QAing them) here in the US before shipping them to customers. You pay for this, obviously, but it means you aren’t dealing with someone in China and begging them to send you a new laser tube if yours arrives busted or something. Boss Laser and OMTech are two brands I know of… although Boss has/had a mixed reputation back on Reddit’s /r/lasercutting and not sure if they have changed.

Right now, OMTech is selling a 100W 20"x28" (presumably 500mm x 750mm) unit that looks exactly like my generic Chinese machine for $3800 USD. That’s only $800 more than I paid for mine used, locally… and it has a 2 year warranty. Not bad IMO.

If that’s too much, you can drop in power down to a 60W or 40W unit, although after using a 60-70W unit at TechShop a few years ago I decided I didn’t want less than a 100W one; it just seems to give you a lot more options especially for cutting and vector engraving.

And of course if you have money to burn (or someone else’s money) then you can get a “real” prototyping laser like an Epilog… they are sweet machines but dear lord you pay for it.

I have not engraved rock on my current laser, but several years back at TechShop (still bitter they are gone) I did some slate tiles and they came out well. I don’t know where they were sourced from because I found them lying around.

I didn’t change the laser lens or do anything out of the ordinary for it. I think they had a little stick that was cut to the laser’s focal distance, and I used that to focus it right on the surface of the stone.

It left a slightly rough, matte white surface where I had engraved. This was probably at maybe 30-50W with air assist on?

Not sure what results you would get from other kinds of rock, e.g. granite. My gut says you’d want to avoid rock with lots of reflective crystals in it, e.g. quartz or silica-bearing rock, but I don’t have any solid evidence for that.