Texture Trick for 3D Prints From the Stone Age

Arguably one of the most difficult aspects of 3D printing is trying to make the finished product look like it wasn’t 3D printed. It can take a lot of time and work to cover up the telltale layer lines (or striations, if you want to get fancy), especially if your 3D printer isn’t perfectly calibrated. While there aren’t many shortcuts to achieve a glass-like finish on 3D printed parts, if your end goal is to make something that looks like stone, [Wekster] has a tip for you.

He demonstrates the technique by building a gorgeous recreation of the main gate from Jurassic Park. The process gives the relatively smooth plastic the gnarled look of rough-hewn stone with very little in the way of manual work. While it’s true there’s no overabundance of projects this stone-look finish will work for, it’s definitely something we’ll be filing away mentally.

So what’s the secret? [Wekster] first coats the 3D printed parts with common wood filler, the sort of stuff available at any hardware store. He then wraps them in clear plastic wrap, allowing the wrap to bunch up rather than trying to pull it taught. For extra detail, he digs into the plastic wrap here and there to create what will appear to be gaps and cracks on the finished piece. The wood filler is then left to dry; a process which normally only takes a few minutes, but now will take considerably longer as the plastic wrap will be keeping the air from it.

Once its hardened and unwrapped, [Wekster] sprays it with a base coat of color, and follows up with a few washings with watered down black and gray paints. This technique is well known to anyone who’s done miniature or model painting; serving to highlight the surface texture and give the finish more depth. With this method, anything that resembles a layer line in the print is long gone, and the surface looks so complex and detailed that at first glance few would believe it’s plastic.

[Wekster] also used wood filler during the finishing process for his Fallout 4 “Thirst Zapper” replica. In the past we’ve shown how you can smooth out 3D printed parts with epoxy and taken a very scientific look at using UV resin as a conformal coating, but maybe it’s time we give wood filler a shot.

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Gaming System Built With Kite, The DIY Android Kit

As a gamer, [Lexie Dostal] dreamed of a smartphone that was a viable gaming platform: something with enough power to run the games and emulators he was interested in, with the controls to make playing them feel natural. So when he got his hands on an early version of Kite, the modular open hardware platform designed to be hacked and customized, that’s exactly what he decided to build. The Kite kit would provide the touch screen and Android-equipped motherboard, he just needed to design a case and integrate controls to make it a real gaming device.

The case design [Lexie] came up with is inspired by the bottom half of the Nintendo 3DS, and ended up only a few centimeters wider than the stock case from the Kite kit. Unfortunately, his delta 3D printer wasn’t large enough to fit the device’s case, so he ended up having to break it into five separate pieces and glue them together. With the case in one piece he worked his way from 220 to 400 grit sand paper, filling any voids in the print with glue as he went. A few coats of primer, more sanding, and a final matte texture spray give the final case a very professional-looking finish.

Not only was the Nintendo 3DS an inspiration for the device, it was also a donor for some of the parts. The directional pad, analog “nub”, and buttons are replacement 3DS hardware, which is interfaced to the KiteBoard with an Arduino Nano. When he couldn’t find springs small enough to use for the shoulder buttons, he bought some thin music wire and wound them himself. Talk about attention to detail.

There’s quite a bit of gear packed into the case, but [Lexie] thinks there’s probably still room to make some improvements. He could free up some room by dropping the connectors and soldering everything directly, and says he’d like to come up with a custom PCB to better interface with the 3DS’s hardware to cut down on some of the wiring required. With the extra room he thinks the battery, currently a 3200 mAh pack designed for the LG V20 smartphone, could probably be replaced with something even bigger.

Readers may recall that the Kite is currently in the running for the 2018 Hackaday prize. Seeing Kite already delivering on the promise of making it easier to develop powerful Android devices is very exciting, and we can’t wait to see what else hackers will be able to do with it.

How to Put the ‘Pro’ in Prototype

It’s easy to get professional-quality finishes on your prints and prototypes if you take the right steps. In the final installment of his series about building with Bondo, product designer [Eric Strebel] shows us how it’s done no matter what the substrate.

How does he get such a smooth surface? A few key steps make all the difference. First, he always uses a sanding block of some kind, even if he’s just wrapping sandpaper around a tongue depressor. For instance, his phone holder has a round indent on each side. We love that [Eric] made a custom sanding block by making a negative of the indent with—you guessed it—more Bondo and a piece of PVC. The other key is spraying light coats of both primer and paint in focused, sweeping motions to allow the layers to build up.

If you need to get the kind of surface that rivals a baby’s behind, don’t expect to prime once, paint once, and be done with it. You must seek and destroy all imperfections. [Eric] likes to smooth them over with spot putty and then wet sand the piece back to smooth before applying more primer. Then it’s just rinse and repeat with higher grits until satisfied.

There’s more than one way to smooth a print, of course. Just a few weeks ago, our own [Donald Papp] went in-depth on the use of UV resin.

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Gramazon Gives Your Echo Dot a 1920’s Makeover

Unless you’re particularly fond of hockey pucks, you probably aren’t really keen on the aesthetics of the NSA’s Amazon’s diminutive listening device, the Echo Dot. It’s not exactly ugly, but if anyone at Amazon spent more than ten minutes considering the visual design of the thing when it was being developed, we’d be shocked.

Luckily for us, there are hackers and makers who not only have the artistic chops to come up with visually appealing designs, but are kind enough to share them with those of us who are a few crayons short of a full box in that department. Such is the case with the jaw-dropping Gramazon by [Bård Fleistad], a 3D printed acoustic amplifier for the Echo Dot that converts the ho-hum looking device into a classic 1920’s style “horn” speaker.

[Bård] has wanted a horn speaker for awhile, but the prices on a real one in decent condition are getting pretty high. If he couldn’t have the real deal he figured the next best thing would be to 3D print his own version, but he’d still need electronics to put into it. Since the Echo is readily available and works as a Bluetooth speaker (not to mention plays audio from various online sources), it made sense to use it as the heart of his faux-horn.

The design he came up with is very slick, but the finish work on the printed parts is really what puts this project over the edge. [Bård] used Bondo and multiple primer coats to smooth the outside of the horn, and XTC-3D for the hard-to-reach internal curves. Plus sanding. Lots, and lots, of sanding.

If you’re looking for more information on putting high quality finishes on your 3D printed parts like this, check out our Visual 3D Print Finishing Guide. Or if you’d rather just find a swanky home for your always-listening hockey puck, we’ve got plenty of inspiration for you there as well.

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Visual 3D Print Finishing Guide

With 3D printers now dropping to record low prices, more and more people are getting on the additive manufacturing bandwagon. As a long time believer in consumer-level desktop 3D printing, this is a very exciting time for me; the creativity coming out of places like Thingiverse or the 3D printing communities on Reddit is absolutely incredible. But the realist in me knows that despite what slick promotional material from the manufacturers may lead you to believe, these aren’t Star Trek-level replicators. What comes out of these machines is often riddled with imperfections (from small to soul crushing), and can require considerable cleanup work before they start to look like finished pieces.

If all you hope to get out of your 3D printer are some decent toy boats and some low-poly Pokemon, then have no fear. Even the most finicky of cheap printers can pump those out all day. But if you’re looking to build display pieces, cosplay props, or even prototypes that are worth showing to investors, you’ve got some work cut out for you.

With time, patience, and a few commercial products, you can accomplish the ultimate goal: turning a 3D printed object into something that doesn’t look like it was 3D printed. For the purposes of this demonstration I’ll be creating a replica of the mobile emitter used by the “Emergency Medical Hologram” in Star Trek: Voyager. I can neither confirm nor deny I selected this example due to the fact that I’m currently re-watching Voyager on Netflix. Let’s make it look good.

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