How To Make Bisected Pine Cones Look Great, Step-by-Step

February 10, 2019 by Donald Papp 8 Comments

[Black Beard Projects] sealed some pine cones in colored resin, then cut them in half and polished them up. The results look great, but what’s really good about this project is that it clearly demonstrates the necessary steps and techniques from beginning to end. He even employs some homemade equipment, to boot.

Briefly, the process is to first bake the pine cones to remove any moisture. Then they get coated in a heat-activated resin for stabilizing, which is a process that infuses and pre-seals the pine cones for better casting results. The prepped pine cones go into molds, clear resin is mixed with coloring and poured in. The resin cures inside a pressure chamber, which helps ensure that it gets into every nook and cranny while also causing any small air bubbles introduced during mixing and pouring to shrink so small that they can’t really be seen. After that is cutting, then sanding and polishing. It’s an excellent overview of the entire process.

The video (which is embedded below) also has an outstanding depth of information in the details section. Not only is there an overview of the process and links to related information, but there’s a complete time-coded index to every action taken in the entire video. Now that’s some attention to detail.

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Word Clock Don’t Need No Stencil Font

December 26, 2018 by Lewin Day 9 Comments

Word clocks use natural language to display the time. They’ve been in vogue in the last 20 years or so, as low-cost digital technology makes them particularly cost effective and easy to build for the average maker. The hardware and software is a solved problem, so presentation is everything. Luckily, [watsaig]’s effort does not disappoint.

The build began with a timeframe of just seven days — a narrow window given [watsaig]’s lack of experience with lasercutting and woodworking. Not content to let that get in the way, it was time to get to work. Wood was sourced from Amazon and designs laid out, before lasercutting began in earnest.

[watsaig] decided to fill all of the letters with epoxy to achieve a flat finished surface that also served as diffuser for the LEDs. To avoid using an unsightly stencil font, the centers (the cut out portion) of letters like O, A, and R had to be placed by hand. Unfortunately his turned out quite badly. When using a squeegee method to work epoxy into the letters, the inserts tended to shift, ruining the face plate.

Undeterred, the clock face was recreated from scratch, and it was determined that a pipette was a far more suitable tool, allowing the letters to be filled with epoxy without unduly disturbing the letter inserts. The final result is visually attractive, finished with a wonderful stain and giving a pleasing glow thanks the careful attention to diffusion and masking. The hidden Happy Birthday message may have been lost in the rush, but it’s the thought that counts, after all.

For a Continental take, check out this word clock in Catalan.

Epoxy Too Thin? Use Wood Flour As A Thixotropic Filler

December 23, 2018 by Donald Papp 27 Comments

The world of glues is wide and varied, and it pays to use the right glue for the job. When [Eric] needed to stick a wide and flat 3D printed mount onto the back of a PCB that had been weatherproofed with an uneven epoxy coating, he needed a gap-filling adhesive that would bond to both surfaces. It seemed like a job for the hot glue gun, but the surface was a bit larger than [Eric] was comfortable using with hot glue for. The larger the surface to be glued, the harder it is to do the whole thing before hot glue cools too much to bond properly.

What [Eric] really wanted to use was a high quality two-part epoxy that he already had on hand, but the stuff was too runny to work properly for this application. His solution was to thicken it with a thixotropic filler, which yields a mixture that is akin to peanut butter: sticky, easily spread to where it’s needed, but otherwise stays in place without dripping or sagging and doesn’t affect bonding.

3D printed pad stuck to back of PCB with thickened epoxy.

Common thixotropic fillers include ground silica or plastic fibers, but [Eric]’s choice was wood flour. Wood flour is really just very fine sawdust, and easily obtained from the bag on his orbital sander. Simply mix up a batch of thin two-part epoxy and stir in some wood flour until the sticky mixture holds its shape. Apply as needed, and allow it to cure.

Thanks to this, [Eric] was able to securely glue a 3D printed pad to the back of his animated LED snowflakes to help mount them in tricky spots. Whether for small projects or huge installations, LEDs, PCBs, and snowflakes are a good combination.

The Dual In-Line Package And How It Got That Way

November 8, 2018 by Dan Maloney 68 Comments

For most of human history, our inventions and innovations have been at a scale that’s literally easy to grasp. From the largest cathedral to the finest pocket watch, everything that went into our constructions has been something we could see with our own eyes and manipulate with our hands. But in the middle of the 20th century, we started making really, really small stuff: semiconductors. For the first time, we were able to create mechanisms too small to be seen with the naked eye, and too fine to handle with our comparatively huge hands. We needed a way to scale these devices up somewhat to make them useful parts. In short, they needed to be packaged.

We know that the first commercially important integrated circuits were packaged in the now-familiar dual in-line package (DIP), the little black plastic millipedes that would crawl across circuit boards for the next 50 years. As useful and versatile as the DIP was, and for as successful as the package became, its design was anything but obvious. Let’s take a look at the dual in-line package and how it got that way.

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These 3D Printed Supports Can Take Hard Use, Thanks To Resin Filling

September 29, 2018 by Donald Papp 16 Comments

Liquid two-part resins that cure into a solid are normally used for casting, and [Cuddleburrito] also found them useful to add strength and rigidity to 3D printed pillar supports. In this case, the supports are a frame for some arcade-style buttons, which must stand up to a lot of forceful mashing. Casting the part entirely out of a tough resin would require a mold, and it turns out that filling a 3D print with resin gets comparable benefits while making it easy to embed fastener hardware, if done right.

Cap design shows how the nut will be encased and the cap anchored even if the pillar is slightly underfilled with resin. The screw can be backed out after the resin cures.

Filling the inside of an object with some kind of epoxy or resin to reinforce it isn’t a new idea, but [Cuddleburrito] learned how a few small design considerations can lead to less messy and more successful results. The first is that resin can be poured with screws in place without any worry of trapping the screws in the resin, if done correctly. As long as only the threads of the screw are in the resin, they can be backed out after the resin has cured. Embedding nuts into the resin to act as fasteners becomes a much easier task when one can simply pour resin with both nut and screw in place, and remove the screw afterwards. A thin layer of a lubricant on the threads to act as a release may help, but [Cuddleburrito] didn’t seem to need any.

The second thing learned was that, for a pillar that needs a cap and embedded nut on both ends, it can be tricky to fill the object’s void with the perfect amount of required resin before capping it off. On [Cuddleburrito]’s first attempt, he underfilled and there wasn’t enough resin to capture the nut on the top lid of the pillar he was making. The way around this was to offset the nut on a riser, and design in either a witness hole or an overflow relief. A small drain hole or a safe area for runoff allows for filling things right up without an uncontrolled mess in the case of overfilling.

Something worth keeping in mind when experimenting in this area is that in general the faster a resin cures, the more it heats up in the process. It may be tempting to use something like 5 minute epoxy in a pinch, but the heat released from any nontrivial amount of it risks deforming a thin-walled 3D print in the process. For cases where resin would be overkill and the fasteners are small, don’t forget we covered the best ways to add fasteners directly to 3D printed parts.

Epoxy Fix For A Combusted PCB

September 26, 2018 by Dan Maloney 29 Comments

When the Magic Smoke is released, chances are pretty good that you’ve got some component-level diagnosis to do. It’s usually not that hard to find the faulty part, charred and crusty as it likely appears. In that case, some snips, a new non-crusty part, and a little solder are usually enough to get you back in business.

But what if the smoke came not from a component but from the PCB itself? [Happymacer] chanced upon this sorry situation in a power supply for an electric gate opener. Basking in the Australian sunshine for a few years, the opener started acting fussy at first, then not acting at all. Inspection of its innards revealed that some unlucky ants had shorted across line and neutral on the power supply board, which burned not only the traces but the FR4 of the board as well. Rather than replace the entire board, [Happymacer] carefully removed the carbonized (and therefore conductive) fiberglass and resin, leaving a gaping hole in the board. He fastened a patch for the hole from some epoxy glue; Araldite is the brand he used, but any two-part epoxy, like JB Weld, should work. One side of the hole was covered with tape and the epoxy was smeared into the hole, and after a week of curing and a little cleanup, it was ready for duty. The components were placed into freshly drilled holes, missing traces were replaced with wire, and it seems to be working fine.

This seems like a great tip to keep in mind for when catastrophe strikes your boards. There are more extreme ways to do it, of course, but perhaps none so flexible. After all, epoxy is versatile stuff.

Epoxy Embedded Electronic Art Running On Pyramid Power

September 2, 2018 by Steven Dufresne 25 Comments

We sometimes get our inspirations from art. When [kodera2t] saw some Japanese art of fish drawings embedded in clear epoxy he just had to make his own. But while skilled in electronics, he wasn’t skilled at drawing. We’d still call him an artist, though, after seeing what he came up with in his electronics embedded in crystal clear epoxy.

His first works of electronic art were a couple of transistors and some ICs, including an 80386, encased in epoxy. But then he realized that he wanted the electronics to do something interesting. However, once encased in epoxy, how do you keep the electronics powered forever?

He tried a solar cell charging a battery which then powered an LED but he didn’t like the idea of chemical batteries encased in epoxy for a long time.

He then switched to wireless power transmission with a receiving coil in the base of epoxy pyramids. For one of them, the coil powers a BLE board with an attached LED which he can control from his phone. And his latest contains an ESP32-PICO with an OLED display. The code allows him to upload new firmware over the air but on his Hackaday.io page, he shows the difference between code which can brick the ESP32 versus code which won’t. But don’t take our word for it. Check out the video below to see his artistry for yourself.

While embedding electronics in epoxy is new to [kodera2t], we’ve seen it a few times before. once in the form of an amplifier circuit done beautifully, dead bug style, and a more experimental attempt with a solar lantern.

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