Making PLA stick to a 3D printer build platform by using hairspray or an acetone ABS slurry

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[Chris] has been having some real problems getting PLA to stick to the build platform of his Printrbot. This is of course not limited to this brand of printers, and affects all extruder-based hardware using the PLA as a source material. He came up with a couple of ways to fix the problem.

The first is something we’re quite familiar with. The image above shows [Chris] applying a thin layer of hairspray to the platform. This is a technique the we use with our own 3D printer. The sheets of paper are used as a mask to help keep the sticky stuff off of the threaded rod. For more info on the hairspray trick [Chris] recommends that you read this article.

The second technique uses a slurry made from saturating a bottle of acetone with ABS leftovers. In the clip after the break he shows off a glass jar of the solvent with scraps from past print jobs hanging out inside. After a couple of days like that it’s ready to use. He takes a paper towel, wets it with the solution, and wipes on a very small amount. He does mention that this will eventually eat through the Kapton tape so apply it rarely and sparingly.

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Smoothing 3D Prints with Acetone Vapor

Acetone Smoothed Prints

If you’ve ever used an extruding 3D printer, you know that the resulting prints aren’t exactly smooth. At the Southackton hackerspace [James] and [Bracken] worked out a method of smoothing the parts out using vapor. The method involves heating acetone until it forms a vapor, then exposing ABS parts to the vapor. The method only works with ABS, but creates some good looking results.

Acetone is rather flammable, so the guys started out with some safety testing. This involved getting a good air to fuel mixture of acetone, and testing what the worst case scenario would be if it were to ignite. The tests showed that the amount of acetone they used would be rather safe, even if it caught fire, which was a concern several people mentioned last time we saw the method.

After the break, [James] and [Bracken] give a detailed explanation of the process.

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More acetone-vapor polishing experiments

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If you’re thinking of trying the acetone-vapor polishing process to smooth your 3D printed objects you simply must check out [Christopher's] experiments with the process. He found out about the process from our feature a few days ago and decided to perform a series of experiments on different printed models.

The results were mixed. He performed the process in much the same way as the original offering. The skull seen above does a nice job of demonstrating what can be achieved with the process. There is a smooth glossy finish and [Christopher] thinks there is no loss of detail. But one of the three models he tested wasn’t really affected by the vapor. He thinks it became a bit shinier, but not nearly as much as the skull even after sending it through the process twice. We’d love to hear some discussion as to why.

There is about eight minutes of video to go along with the project post. You’ll find it after the jump.

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Stuffing an RFID Card into a Finger Ring

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[Benjamin Blundell] loves wearable technology — but isn’t very happy with commercial offerings — at least not yet. He wanted to take one of his personal RFID cards, and fit it into a much smaller form factor, a 3D printed RFID ring.

The cool thing with most RFID cards today is they are made of a plastic that is quite easily dis-solvable in Acetone. Simply soak the card for about 30 minutes (depends on the card) and the plastic will simply peel away, revealing the microchip and copper antenna coil. It kind of looks alive when it’s melting…

The problem is, the antenna coil is generally the size of the card — how exactly are you going to fit that into a ring? [Benjamin] managed to find some surrogate RFID key tags, with a much smaller antenna coil. A little bit of solder later and he was able to attach his RFID microchip onto the new antenna! He mentions it is possible to wind your own antenna… but to get the frequency just right might be a bit challenging.

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[CNLohr] Demos His Photoetch PCB Process

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If you’re going to learn something, it only makes sense to learn from a master. [CNLohr] is known around these parts for his fablous PCBs, and he’s finally started to document his entire fabrication process.

[CNLohr] is using a photoetch process, where a mask is created with a laser printer on overhead transparencies. He covers the copper clad boards with a Riston photosensitive mask—available here, and they accept Bitcoin—sent through a laminator, and exposed with the laser printed mask and a UV grow bulb. After the mask has developed, [CNLohr] drops his boards into a ferric chloride bath that eats away the unexposed copper. He then removes the photomask with acetone and cuts the boards with a pair of aircraft snips, and they’re ready to be soldered up with components.

Yes, home PCB etching tutorials are pretty much a solved problem, but [CNLohr]‘s work speaks for itself. He’s also the guy who made a microcontroller/Linux/Minecraft thing on a glass microscope slide. Learning from a guy with these skills means you’re learning from one of the best.

Video below, and there’s also a video going over the design of a PCB using KiCAD (!) and TopoR (!!!) available here.

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Polishing optics milled from acrylic

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[Ben Krasnow] milled some lenses out of cast acrylic and needed a way to get an optical finish on the tool-marked surface. He tested several acrylic finishing methods to achieve a crystal clear finish. The tests were done using flat chunks. A regiment of sandpaper, from coarse to fine, was used as the first stage of the operation. From there [Ben] sought out the best finishing step, starting with hand polishing tests, flame polishing, and methylene chloride vapor polishing (which is something along the lines of acetone vapor polishing for 3D printed ABS parts).

Flame polishing and vapor polishing are not really exact sciences… at least in the tests he performed. It was difficult to know exactly how long to expose the acrylic. Too short or too long resulted in poor clarity. Watch his video to get a look at all results. We’d say the the easiest way to make milled acrylic clear without achieving an optical finish is to flame polish it as it doesn’t really require that you sand it ahead of time. But [Ben's] tests prove that you can’t beat hand polishing with 600 then 2000 grit sandpaper before finishing up with a liquid plastic polish.

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The definitive guide to solder stencils

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Yes, we’ve seen our share of tutorials for making solder paste stencils, but [Felix] hit it out of the park with this one. It’s the definitive guide to making solder stencils at home, with quality as good as you would find in any professionally made stencil.

The material for the stencils comes from the same source as so many other DIY solder stencils – aluminium cans. The interior plastic coating and the exterior paint job are both removed with heat, acetone, and patience. After laying out the cream layer of his board in a PDF file, [Felix] used a fairly interesting transfer medium to get the toner onto the aluminum; cheap vinyl shelving paper attached to a piece of paper apparently makes for an ideal surface to transfer toner.

After transfer, the board is etched with HCl and peroxide. [Felix] is getting some very good results with his method, including a few very fine pitch IC footprints. It’s just as good as a professionally made, laser cut stainless stencil, and you probably already have all the necessary ingredients lying around your house. That’s a win anytime.