Sometimes we manage to miss projects when they first appear, only to have the joy of discovering them a while later. So it is with [John Opsahl]’s Project Convert To Paint, a CNC painting ‘bot that takes a bitmap image and paints it on canvas as a fine artist would, with a real brush, and paints.
It was first created for the 2017 robotart.org competition, and takes the form of a fairly standard CNC gantry machine. It departs from the norm in its chuck however, as it has what is described as a universal artist chuck, capable of holding a variety of artistic implements. The images are converted from bitmap to vector format, and thence to gcode with the help of a bit of custom Python code.
He’s at pains to say that simply because an image can be converted to a paintable format does not mean that it will produce a good picture. But some of the results are rather impressive, delivering anything from a pointilist effect to a broader brush stroke. We can see that with a bit of experience in the processing it would be possible to create a veritable gallery of masterpieces.
Let’s say you’ve watched a few episodes of “The Joy of Painting” and you want your inner [Bob Ross] to break free. You get the requisite supplies for oil painting – don’t forget the alizarin crimson! – and start to apply paint to canvas, only to find your happy little trees are not so happy, and this whole painting thing is harder than it looks.
[Saint Bob] would certainly encourage you to stick with it, but if you have not the patience, a CNC painting robot might be a thing to build. The idea behind [John Opsahl]’s “If Then Paint” is not so much to be creative, but to replicate digital images in paint. Currently in the proof-of-concept phase, If Then Paint appears to have two main components: the paint management system, with syringe pumps to squeeze out different paints to achieve just the right color, and the applicator itself, a formidable six-axis device that supports tool changes by using different brushes chucked up into separate hand drill chucks. The extra axes at the head will allow control of how the brush is presented to the canvas, and also allow for cleaning the brush between colors. The videos below show two of the many ways [John] is exploring to clean the brushes, but sadly neither is as exciting as the correct [Bob Ross] method.
It looks like If Then Paint has a ways to go yet, but we’re impressed by some of the painting it has produced already. This is just the kind of project we like to see in the 2019 Hackaday Prize – thought out, great documentation, and a lot of fun.
Vantablack is the darkest pigment ever created, capable of absorbing 99.96% of visible light. If you cover something in Vantablack, it turns into a black hole. No detail is presented, and physical objects become silhouettes. Objects covered in Vantablack are outside the human experience. The mammalian mind cannot comprehend a Vantablack object.
Vantablack is cool, but it’s also expensive. It’s also exclusively licensed by [Anish Kapoor]’s studio for artistic use. Understandably, artists have rebelled, and they’re making their own Vantablack-like pigments. Now, the World’s Blackest Black is on Kickstarter. You can get a 150 ml bottle of Black 3.0, something that’s almost black as Vantablack, for £10.
The pigment for Black 3.0 is called Black Magick, and yes, there was a version 2.0 The problem with the earlier version is that although the pigment was blacker than almost anything else, paint isn’t just pigment. You need binders. The new formulation uses a new acrylic polymer to hold the pigment, and ‘nano-mattifiers’ to make the paint none more matte.
What can you do with the blackest black paint you’ve ever seen? Well, taking pictures of an object covered in the blackest black is a tiny bit dumb. This is something that must be experienced in person. You could paint a car with it, which is something I really want to see. You could follow [Anish Kapoor] around in the shadows. Use it as a calibration target. Who knows what we’ll do with the almost-Vantablack when everyone has it.
There was a time when most 3D printers used ABS plastic. It stinks, is probably bad for you, and tends to warp unless printed in a heated enclosure. So most people have gone to something else, mostly PLA. But ABS also dissolves in a readily-available solvent, acetone, and this is useful for smoothing the layer artifacts from a 3D print. [3DSage] has a technique that works for PLA or — he says — probably any filament. You can see what he’s doing in the video below.
The video starts out with a recap of things most Hackaday readers will already know. But hang in there because at about 1:20, he reveals his method.
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.
There’s no beating the beauty and durability of a high-quality powder-coated part. There’s just something about the look and feel of the finish that goes far beyond mere painting and makes it worth the effort and expense. The typical electrostatic spray powder-coating setup can be expensive, though, and not necessarily suitable for every workpiece.
Enter the fluidized-bed powder coating chamber, perfect for limited runs of small parts, and the brainchild of [Andrew Mayhall]. With a business providing furniture kits based on iron pipe, [Andrew] needed a way to finish flanges and fittings, and powder coating provided the best look. The fluidizer he built is a great alternative to spray coating; it blows air through a bed of fine thermoplastic granules, which causes them to act like a fluid. It’s similar to the fluidized-bed hot tub we recently featured, but on a much smaller scale and with different requirements based on the ultrafine particle size and aggregation properties of the powder. [Andrew] had to add mechanical agitation to achieve a homogeneous fluid bed, and after much experimentation he’s now able to dip preheated parts into the bed and achieve one-step powder coating. The video after the break shows some of the operational details.
There’s talk of robots and AIs taking on jobs in many different industries. Depending on how much stock you place in that, it might still be fair to say the more creative fields will remain firmly in the hands of humans, right?
Estonian inventor [Mihkel Joala] — also working at SprayPainter — successfully tested his prototype by painting a 30m tall mural on a smokestack in Tartu, Estonia. The creative procedure for this mural is a little odd if you are used to the ordinary painting process: [Joala] first takes an image from his computer, and converts it into a coordinate grid — in this case, about 1.5 million ‘pixels’. These pixels are painted on by a little cart loaded with five colours of spray paint that are able to portray the mural’s full palette once combined and viewed at a distance. Positioning is handled by a motor at the base of the mural controlling the vertical motion in conjunction with tracks at the top and bottom which handle the horizontal motion.
For this mural, the robot spent the fourteen hours trundling up and down a set of cables, dutifully spraying the appropriate colour at such-and-such a point resulting in the image of a maiden cradling a tree and using thirty cans of spray paint in the process.