PTC Heaters For Reflow Soldering

May 21, 2016 by Jenny List 12 Comments

Reflow soldering – setting components on a PCB in blobs of solder paste and heating the whole assembly at once to melt all joints simultaneously – has been the subject of many ingenious hacks. Once it was the sole preserve of industrial users with specialist microprocessor-controlled ovens, now there are a myriad Arduino-controlled toaster ovens, hot air blowers, and hotplates that allow hackers and makers to get in on the reflow act too.

This morning a fresh idea in the reflow soldering arena has come our way. It’s not the most earth-shattering, but it does have some advantages so is worth a second look. [Analog Two] has successfully used a PTC heating element as a reflow soldering hotplate.

PTC heating elements are thermistors with a positive temperature coefficient. As their temperature rises, so does their electrical resistance. By careful selection of materials they can be manufactured with a sharp increase in resistance at a particular temperature. Thus when an electrical current is passed through them they heat up until they reach that temperature, then the current decreases as the resistance goes up, and they do not heat beyond that point. Thus as heaters they are intrinsically self-regulating. From our point of view they have another advantage, they are also cheap. Fitted as they are to thousands of domestic heating products they are readily available, indeed [Analog Two] found his on Amazon.

The heater chosen was a 200W 110V model with a temperature of 230 Celcius to match the solder he was using. They are also available for other mains voltages, and even at 12 and 24V for automotive applications. He reports that the time to reflow was about 90 seconds.

We’ve mentioned the advantages of this heater as its price and regulated temperature. Looking at the pictures though a disadvantage is its size. This is a reflow plate for small boards. There are larger PTC heater elements available though, it would be interesting to hear people’s experiences reflowing with them.

Hotplates for reflow soldering have featured before a few times here at Hackaday. We recently had this tiny plate, but we’ve also had a PID-controlled plate, and an Arduino-controlled domestic hotplate. We’re sure this is an avenue with further to go.

Shaper Tools Will Blow Your Mind

May 20, 2016 by Gerrit Coetzee 73 Comments

Have you ever wanted to own a full-sized ShopBot? What if some geniuses somewhere made a tool the size of a coffee maker that had the same capabilities? Does an augmented reality, real-time feedback, interactive, handheld CNC router that can make objects ranging in size from a pillbox to an entire conference room table sound like a thing that even exists? It didn’t to me at first, but then I visited the Shaper Tools office in San Francisco and they blew my mind with their flagship tool, Shaper Origin.

This table and the spool holder sitting on it was made with a machine the size of a coffee maker.

It’s impossible for me not to sound like a fan boy. Using Shaper Origin was one of those experiences where you just don’t know what to say afterwards. This is what the future looks like.

I’ve used a lot of CNC tools in my life, from my first home-built CNC conversion, to 1980s monstrosities that ran off the floppy kind of floppy disks, and all the way over to brand new state-of-the-art vertical machining centers. I had to shake a lot of that knowledge off when they demoed the device to me.

Origin is a CNC router built into the form factor of a normal wood router. The router knows where it is on the work piece. You tell it where on the piece you would like to cut out a shape, drill a hole, or make a pocket. It tells you where to go, but as you move it keeps the cutting bit precisely on the path with its three axes of control.

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Beyond WD-40: Lubes For The Home Shop

May 17, 2016 by Dan Maloney 134 Comments

If your shop is anything like mine, you’ve got a large selection of colorful cans claiming to contain the best and absolutely only lubricant you’ll ever need. I’ve been sucked in by the marketing more times than I care to admit, hoping that the next product will really set itself apart from the others and magically unstick all the stuck stuff in my mechanical life. It never happens, though, and in the end I generally find myself reaching for the familiar blue and yellow can of WD-40 for just about every job.

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Improved Digital Caliper Interfacing, Including 3D Printed Connector

May 17, 2016 by Donald Papp 42 Comments

[MakinStuff] wrote in to let us know about a project he did for new and improved interfacing to the ubiquitous cheap Chinese digital calipers. Interfacing to this common caliper model is well-trod ground, but his project puts everything about interfacing and reading the data in one place along with some improvements: a 3D printed connector that makes mating to the pads much more stable and reliable, a simple interface circuit for translating the logic levels, and an interrupt-driven sample Arduino sketch to read the data. Making the sketch interrupt-driven means the Arduino never sits and waits for input from the calipers, making it easier have the Arduino do other meaningful work at the same time, ultimately making it easier to incorporate into other projects.

The connector has spaces to insert bare wires to use as contacts for the exposed pads inside the calipers. Add a little hot glue and heat shrink, and you’ll never have to fiddle with a hacked-together connection again.

This common caliper model has been hacked and re-purposed in interesting ways. We’ve seen them used as a Digital Read Out (DRO) on a lathe as well as being given the ability to wirelessly log their data over Bluetooth.

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Propane Tanks Transformed Into Extreme Sandblaster

May 15, 2016 by Dan Maloney 17 Comments

The [Make It Extreme] team has been racking up the builds lately, and a lot of them are heavy with metalworking. When you’re doing that kind of work, and you put as much care into finishing your builds like they do, it’s a good idea to have access to a sandblaster. So naturally, they built a really nice one.

We’ve featured a couple of [Michalis Mavros] and team’s build recently; you’ll no doubt recall this viciously effective looking spot welder and a sketchy angle grinder cum belt sander. The sandblaster build, centered as it is around scrap propane tanks, has some lethal potential, but luckily the team displaced any remaining gas from the tanks with water before doing any cutting. The design allows for a lot of sand in the tanks, with plans to provide a recycling system for the grit, which is a nice touch. And it works great – they even used it to clean it up before final finishing in the trademark [Make It Extreme] green and black paint job.

What we really like about the video, though, is that it’s a high-speed lesson on metalworking techniques. There’s a ton to learn here about all the little tricks needed to bring a large-scale metalworking project to fruition. It also demonstrates that we really, truly need a plasma cutter and a metalworking lathe.

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Taming A Variac With A Thermistor

May 15, 2016 by Jenny List 18 Comments

The folks at TOG, Dublin Hackerspace, have a large variac. A variac is a useful device for testing some fault conditions with AC mains powered equipment, it allows an operator to dial in any AC output voltage between zero, and in the case of TOG’s variac, 250V.

Their problem was with such a magnificent device capable of handling nearly 3KW, it presented an inductive load with a huge inrush current at power-on that would always take out the circuit breakers. Breakers come with different surge current handling capabilities, evidently their building is fitted with the domestic rather than the industrial variants.

Their solution was a simple one, they fitted an NTC surge limiter in series with the variac input. This is a thermistor whose resistance falls with temperature. Thus on start-up it presented an extra 12 ohm load which was enough to keep the breaker happy, but soon dropped to a resistance which left the variac with enough juice.

This is a simple fix to a problem that has faced more than one hackerspace whose imperfect lodgings are wired to domestic-grade spec. In a way it ties in neatly with our recent feature on mains safety; making the transformer no longer a pain to use means that it is more likely to be used when it is needed.

Via: TOG, Dublin Hackerspace.

The Ultimate Traveler’s Toolkit

May 14, 2016 by James Hobson 9 Comments

Looking for a better way to store your tools during transportation? While we certainly wouldn’t recommend trying to check this thing as a carry-on (oh and prepare for it to be searched even in checked luggage), this clever use of a road case is probably one of the best tool boxes we’ve ever seen.

This is [Robb Godshaw’s] tool box. It’s been developed over the past five years as he’s become a skilled maker. You might remember him best from his ironic project “Why are we limited to C-Clamps?” — a clamp offering of the entire alphabet.

He also picked up the road case close to home for Hackaday — at Apex Electronics Surplus in LA — one of our favorite places to find parts. But the most clever part of the project is the way he’s divided the case for different tools.

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