Laser Etching Stainless Steel With Mustard

[Brain] wanted to mark some scissors with his Ortur laser engraver. The problem? The laser won’t cut into the hard metal of the scissors. His solution? Smear the scissors with mustard. No kidding. We’ve heard of this before, and apparently, you can use vinegar, as well, but since the mustard is a paste it is easier to apply. You can see the result in the video, below.

In case you think you don’t need to watch because we’ve already told you the trick, you should know that [Brian] also goes into a lot of detail about preparing single line fonts to get a good result, among a few other tips like improvements to his air assist setup. On a laser cutter, the air assist blows away charred material leaving a clear field of view between the laser and the remaining uncut material. Using a proper air assist can really expand the capabilities of these inexpensive laser cutters — something we recently saw upgraded with a 3D-printed air assist nozzle.

You can buy a commercial marking solution called CerMark Black, but you probably already have mustard. If you are super cheap, you can probably pick up a packet next time you buy a burger somewhere. After all, you don’t need much. Although the video talks about the Ortur, this technique would work with any engraver. We’ve also heard you can do something similar with plaster and alcohol.

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3D Finger Joints For Your Laser Cutter

A laser cutter is an incredibly useful tool and they are often found in maker spaces all over. They’re quite good at creating large two-dimensional objects and by cutting multiple flat shapes that connect together you can assemble a three-dimensional object. This is easier when creating something like a box with regular 90-degree angles but quickly becomes quite tricky when you are trying to construct any sort of irregular surface. [Tuomas Lukka] set out to create a dollhouse for his daughter using the laser cutter at his local hackerspace and the idea of creating all the joints manually was discouraging.

The solution that he landed on was writing a python script called Plycutter that can take in an STL file and output a series of DXF files needed by the cutter. It does the hard work of deciding how to cut out all those oddball joints.

At its core, the system is just a 3D slicer like you’d find for a 3D printer, but not all the slices are horizontal. Things get tricky if more than two pieces meet. [Tuomas] ran into a few issues along the way with floating-point round-off and after a few rewrites, he had a fantastic system that reliably produced great results. The dollhouse was constructed much to his daughter’s delight.

All the code for Plycutter is on GitHub. We’ve seen a similar technique that adds slots, finger-joints, and t-slots to boxes, but Plycutter really offers some unique capabilities.

Putting The Finishing Touches On A 60W Laser

At this point if you’re even remotely interested in home laser cutters, you know about the K40. These imported machines are very impressive considering they only cost around $400 USD, but naturally, quite a few corners had to be cut to get the price down. If you’re looking for something with a bit more punch and much higher build quality, a new breed of 60 watt lasers have started popping up on the usual import sites for around $2,000 USD.

While these more expensive machines are certainly much higher quality than the K40, [Jeremy Cook] found there was still plenty of room for improvement. For example, the machine didn’t have any switch cut off the laser when somebody opens the lid. While we don’t doubt some readers will consider this more of a feature than a bug, it’s hard to believe that a tool that costs this much wouldn’t at least offer such a thing as an option.

Drilling a hole for the ammeter.

[Jeremy] also decided to add his own ammeter so he could see how much power the laser is drawing. While not strictly required for day to day operation, it turns out that the controller in many of these machines has a tendency to push the laser tubes beyond their design limits on the higher power settings. With the spec sheet for your tube and a permanent in-line ammeter, you can verify you aren’t unwittingly shortening the life of your new cutter.

Even if you ignore the modifications [Jeremy] makes in his video, it’s still a very illuminating look at what it takes to get one of these lasers ready for operation. Not only do you have to get the thing out of its shipping crate safely, but you need to come up with some way to deal with the fumes produced and get the water cooling system hooked up. It’s a decent amount of work, but the end results certainly look impressive.

While the K40 is still probably the better bet for new players, it’s good to see that there are some viable upgrades for anyone who’s outgrown their entry level machine but isn’t in a position to spend the money on an Epilog.

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Cutting Balsa Wood With Air (Oh, And A Laser)

[DIY3DTech] likes using his Ortur laser cutter for balsa wood and decided to add an air assist system to it. Some people told him it wasn’t worth the trouble, so in the video below, he compares the results of cutting both with and without the air assist.

The air assist helped clear the cut parts and reduced charring in the wood. The air system clears residue and fumes that can reduce the effectiveness of the laser. It can also reduce the risk of the workpiece catching on fire.

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From Trash PPE To New PPE

As the coronavirus pandemic circles the world, a fact of daily life for millions of people has become the wearing of a face mask. Some people sport colorful fabric masks, but for many, this means the ubiquitous Chinese disposable mask. They have become the litter of our time, which as [blorgggg] notes is something that shouldn’t have to be the case. Their plastic can be recycled and made into other useful things, for example, ear savers similar to the ones many of us were 3D printing earlier in the year.

As you might imagine diving into a pile of used masks can be a little unhygienic, so the first step is to disinfect with alcohol. Then the various layers can be separated and the outer polypropylene ones collected and stacked between baking parchment to be melted on a skillet. The result is a polypropylene sheet that can be laser cut if it is thick enough, and from this are cut the ear savers. It’s not quite as neat a cut as the acrylic sheet we may be used to, but it’s adequate for the task.

While on the subject of masks, earlier in the year we presented a series in whose first part we dissected a selection.

RGB Minecraft Sign Isn’t Just For Looks

This laser cut and LED illuminated version of the Minecraft logo created by [Geeksmithing] looks good enough to occupy a place of honor on any gamer’s shelf. But it’s not just decoration: it can also notify you about your Minecraft’s server status and tell you when players are online by way of its addressable LEDs.

In the first half of the video after the break, [Geeksmithing] shows how the logo itself was built by cutting out pieces of white and black acrylic on his laser cutter. When stacked up together, it creates an impressive 3D effect but also isolates each letter. With carefully aligned rows of RGB LEDs behind the stack, each individual letter can be lit in its own color (or not at all) without the light bleeding into either side.

Once he had a way of lighting up each letter individually, it was just a matter of writing some code for the Raspberry Pi that can do something useful with them. Notifying him when the server goes down is easy enough, just blink them all red. But the code [Geeksmithing] came up with also associates each letter with one of the friends he plays with, and lights them up when they go online. So at a glance he can not only tell how many friends are already in the game, but which ones they are. Naturally this means the display can only show the status of nine friends…but hey, that’s more than we have anyway.

We’ve been seeing people connect the real world to Minecraft┬áin weird and wonderful ways for years now, and it doesn’t seem like there’s any sign of things slowing down. While we recognize the game isn’t for everyone, but you’ve got to respect the incredible creativity it’s inspired in young and old players alike.

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Popping The Hood On The Flux Beamo Laser Cutter

While the K40 has brought affordable laser cutting to the masses, there’s no question that it took a lot of sacrifices to hit that sub-$400 price point. There’s a reason that we’ve seen so many upgrades and improvements made to the base model machine, but for the price it’s hard to complain. That being said, for users who don’t mind spending a bit more money for a more complete out-of-the-box experience, there are other options out there.

One of them is the beamo, from FLUX. [Frank Zhao] recently picked up one of these $1,900 USD laser cutters because he wasn’t thrilled with the compromises made on the K40. Specifically, he really liked the idea of the internal water cooling system. Oddly enough, something about using a garden hose and buckets of water to cool the laser seemed off-putting. Luckily for us, he’s got a technical eye and the free time necessary to do a teardown and objective analysis of his new toy.

The short version of the story is that [Frank] is not only happy with the results he’s getting, but finds the machine to be well designed and built. So if you’re looking for a rant, sorry. But what you will find is a methodical look at each subsystem of the beamo, complete with annotated pictures and the kind of technical details that Hackaday readers crave.

We especially like his attempts to identify parts which might be difficult to source in the future; it looks like the CO2 laser tube might be proprietary, but everything else looks fairly jellybean. That includes the Raspberry Pi 3B that’s running the show, and the off-the-shelf touch screen HDMI display used for the interface. [Frank] did note that FLUX was unwilling to give him the credentials to log into the Pi and poke around, but with direct access to the SD card, it’s not like that will stop anyone who wants to get in.

In a way, laser cutters are in a similar situation today to that desktop 3D printers were in a few years ago. The cheap ones cut so many corners that upgrades and fixes are almost a necessity, and building your own machine is often less expensive than buying a commercial offering with similar specs. While the beamo is still a bit too expensive for the average hobbyist, it’s good to see machines of this caliber are at least coming down out of the 5 figure range.