For a lot of reasons, home etching of PCBs is somewhat of a dying art. The main reason is the rise of quick-turn PCB fabrication services, of course; when you can send your Gerbers off and receive back a box with a dozen or so professionally made PCBs for a couple of bucks, why would you want to mess with etching your own?
Convenience and cost aside, there are a ton of valid reasons to spin up your own boards, ranging from not having to wait for shipping to just wanting to control the process yourself. Whichever camp you’re in, though, it pays to know what’s going on when your plain copper-clad board, adorned with your precious artwork, slips into the etching tank and becomes a printed circuit board. What exactly is going on in there to remove the copper? And how does the etching method affect the final product? Let’s take a look at a few of the more popular etching methods to understand the chemistry behind your boards.
Continue reading “Copper Be Gone: The Chemistry Behind PCB Etching”
[Sebastian] probably didn’t think he was wading into controversial waters when he posted on his experimental method for etching PCBs (in German). It’s not like etching with hydrochloric acid and peroxide is anything new, really; it was just something new to him. But is it even possible these days to post something and not find out just how wrong you are about it?
Sadly, no, or at least so it appears from a scan of [Sebastian]’s tweet on the subject (Nitter). There are a bunch of ways to etch copper off boards, including the messy old standby etchant ferric chloride, or even [Sebastian]’s preferred sodium persulfate method. Being out of that etchant, he decided to give the acid-peroxide method a go and was much pleased by the results. The traces were nice and sharp, the total etching time was low, and the etchant seemed pretty gentle when it accidentally got on his skin. Sounds like a win all around.
But Twitter wouldn’t stand for this chemical heresy, with comments suggesting that the etching process would release chlorine gas, or that ferric chloride is far safer and cleaner. It seems to us that most of the naysayers are somewhat overwrought in their criticism, especially since [Sebastian]’s method used very dilute solutions: a 30% hydrochloric acid solution added to water — like you oughta — to bring it down to 8%, and a 12% peroxide solution. Yes, that’s four times more concentrated than the drug store stuff, but it’s not likely to get you put on a terrorism watch list, as some wag suggested — a hair stylist watchlist, perhaps. And 8% HCl is about the same concentration as vinegar; true, HCl dissociates almost completely, which makes it a strong acid compared to acetic acid, but at that dilution it seems unlikely that World War I-levels of chlorine gas will be sweeping across your bench.
As with all things, one must employ caution and common sense. PPE is essential, good chemical hygiene is a must, and safe disposal of spent solutions is critical. But taking someone to task for using what he had on hand to etch a quick PCB seems foolish — we all have our ways, but that doesn’t mean everyone else is wrong if they don’t do the same.
Continue reading “Different Etching Strokes For Different PCBs, Folks”
With all the cool and useful parts you can whip up (relatively) quickly on a 3D printer, it’s a shame you can’t just print a PCB. Sure, ordering a PCB is quick, easy, and cheap, but being able to print one-offs would peg the needle on the instant gratification meter.
[Peter Liwyj] may just have come up with a method to do exactly that. His Instructables post goes into great detail about his method, which uses an Elegoo Mars resin printer and a couple of neat tricks. First, a properly cleaned board is placed copper-side down onto a blob of SLA resin sitting on the print bed. He tricks the printer into thinking the platform is all the way down for the first layer by interrupting the photosensor used to detect home. He lets the printer go through one layer of an STL file that contains his design, which polymerizes a thin layer of plastic onto the copper. The excess resin is wiped gently away and the board goes straight into a ferric chloride etching bath. The video below shows the whole process.
As simple as it sounds, it looks like it works really well. And [Peter] didn’t just stumble onto this method; he approached it systematically and found what works best. His tips incude using electrical tape as a spacer to lift the copper off the print surface slightly, cleaning the board with Scotchbrite rather than sandpaper, and not curing the resin after printing. His toolchain is a bit uncoventional — he used SketchUp to create the traces and exported the STL. But there are ways to convert Gerbers to STLs, so your favorite EDA package can probably fit in to the process too.
Don’t have a resin printer? Don’t worry — FDM printers can work too.
Continue reading “Put That New Resin Printer To Work Making PCBs”
Anyone who has ever etched their own PCB knows that the waiting is the hardest part. Dissolving copper in ferric chloride takes time, much like developing a Polaroid picture. And although you really should not shake a fresh Polaroid to speed up development, the PCB etching process thrives on agitation. Why wait an hour when you can build a simple PCB shaker and move on to drilling and/or filling in 10 minutes?
We love that [ASCAS] was probably able to build this without reaching past the the spare parts box and the recycling bin. There’s no Arduino or even a 555 — just a 12 VDC geared motor, a DC-DC buck converter, and an externalized pot to control the speed of the sloshing.
It’s hard to choose a favorite hack here between the hinge used to rock this electric seesaw and the crankshaft/armature [ASCAS] made from a sandwich spread lid and a Popsicle stick. Everything about this build is beautiful, including the build video after the break.
Did you know that unlike ferric chloride, copper chloride can be recharged and reused? Here’s a one-stop etching station that does just that.
Continue reading “Now This Is A Maker’s PCB Shaker”
These days, it’s easy to get high-quality custom PCBs made and shipped to your door for under $50. It’s something that was unfathomable only a decade ago, but now it’s commonplace. However, it doesn’t mean that the techniques of home PCB production are now completely obsolete. Maybe you live somewhere a little off the beaten track (Australia, even!) and need to iterate quickly on a project, or perhaps you’d like to tinker with the chemical processes involved. For your learning pleasure, [Emiliano] decided to share some tips on making SMD-ready PCBs with the TinyDice project.
The actual project is to create a small electronic dice, and [Emiliano] touches on the various necessary considerations such as how to decrease power consumption, and how to source good quality, organic random numbers from your local microcontroller. Though its far from an exhaustive discussion on either topic, it shows an understanding of the deeper factors at play here.
However, the real meat of the write-up is the PCB production process. The guide goes through several stages of etching to not only prepare the PCB but also to add solder mask and produce a solder paste stencil as well using an aluminum can. This gives the boards that colored finish we’re all used to and lets the boards be reflowed for easy SMD assembly.
It’s a tidy guide as to how to approach producing your own boards to be used with SMD components, and it’s complete with clear photos and instructions throughout. If you want to take your designs up another notch, why not consider putting your components inside the circuit board?
It’s the little touches that make a project, and a nice nameplate can really tie a retro build together. Such badges are easy enough to make with a CNC machine, but if you don’t have access to machine tools you can put chemistry to work for you with these acid-etched brass nameplates.
The etching method that [Switch and Lever] uses to get down to brass plaques will be intimately familiar to anyone who has etched a PCB before. Ferric chloride works as well on brass as it does on copper, and [Switch and Lever] does a good job explaining the chemistry of the etching process and offers some tips on making up etching solution from powdered ferric chloride. But the meat of the video below is the head-to-head test of three different masking methods.
The first method uses a laser printer and glossy paper ripped from a magazine to create a mask. The toner is transferred to the brass using an office laminator, and the paper removed with gentle rubbing before etching. For the other two candidates he uses a laser engraver to remove a mask of plain black spray paint in one case, or to convert special laser marking paint to a mask in the other.
We won’t spoil the surprise as to which gave the best results, but we think you’ll be pleased with how easy making classy nameplates can be. You can also use electrolytic methods for a deeper etch, but we think acid etching is a little more approachable for occasional use.
Continue reading “Three Ways To Etch Snazzy Brass Nameplates”
Sometimes we get tips that only leave us guessing as to how — and sometimes why — a project was built. Such is the case with this PCB printer; in this case, the build specifics are the only thing in question, because it puts out some pretty impressive PCBs.
All we have to go on is the video after the break, which despite an exhaustive minutes-long search appears to be the only documentation [Androkavo] did for this build. The captions tell us that the printer is built around the guts from an Epson Stylus Photo 1390 printer. There’s no evidence of that from the outside, as every bit of the printer has been built into a custom enclosure. The paper handling gear has been replaced by an A3-sized heated flatbed, adjustable in the Z-axis to accommodate varying board thicknesses. The bed runs on linear rails that appear custom-made. Under the hood, the ink cartridges have been replaced with outboard ink bottles in any color you want as long as it’s black. The video shows some test prints down to 0.1 mm traces with 0.1 mm pitch — those were a little dodgy, but at a 0.2 mm pitch, the finest traces came out great. The boards were etched in the usual way with great results; we wonder if the printer could be modified to print resist and silkscreens too.
[Androkavo] seems to have quite a few interesting projects in his YouTube channel, one of which — this wooden digital clock — we featured recently. We’d love to learn more about this printer build, though. Hopefully [Androkavo] will see this and comment below.
Continue reading “Heavily Hacked Printer For DIY PCBs”