SMD Soldering with Gas

[desimon] had a wanted to use some accelerometer chips, but their 3x3mm 16-VFQFN packages made it pretty darn hard to solder by hand. While there are endless ways to approach this, we found this one peculiarity interesting from his use of a gas torch, though it is pretty much hot air reflow.

A PCB for the tiny devices is etched and tinned, the pads have a healthy but not overdone amount of solder applied to them. A liberal coat of flux, rough alignment of the chip and a few gentle passes from the torch and the hobby grade solder melts while the surface tension pulls everything into final alignment.

Having personally used a hot air gun a number of times (and also burning my hand about the same number of times) the localized heat of the torch does make more sense, and there is virtually no heat up time for it either, though it appears just as easy to scorch the board. It is a live flame so be careful!

Electronics tutorial two-fer: soldering skills and wires


There is a plethora of electronics tutorials scattered about online. Sometimes it can be hard to separate the good ones from the bad, and the enlightening from the misinformed. We recently came across a pair that we found helpful, and thought they would appeal to anyone starting off in electronics.

In this video tutorial, [Dave Jones] at the EEVblog covers soldering, detailing good practices and common mistakes to avoid when working with through-hole components. As the second video in a series he picks up where part one left off, excitedly demonstrating the ins and outs of good soldering skills.

Hackaday reader [grenadier] is working on a series of beginner’s electronics tutorials, and this week’s entry covers wiring. He discusses wire types, gauges, and even provides a nifty self-computing chart that calculates power loss based on the length and gauge of the selected wire. Before wrapping things up, he briefly touches on fuses and the pitfalls of choosing wire that’s not up to the task at hand. While you’re over there looking over his tutorial, be sure to check out the Junkbox, there’s plenty of awesome stuff to be had!

Cleaning flux from PCBs the easy way

While we’re all for building circuits on protoboard or constructing a deadbug circuit for a last minute project, it’s always nice to see a proper PCB now and again. We think that leftover flux can sometimes make even the nicest of circuit boards look a bit dingy, and Hackaday reader [RandomTask] wholeheartedly agrees. He wrote in to share a method he found online that he uses to get his PCBs squeaky clean after soldering.

The secret to his clean PCBs is a product called Poly Clens. It’s essentially a paint brush cleaner that does a great job at removing flux without having to resort to using a brush to scrub it off the board. [RandomTask] simply submerges his newly assembled board in a small container filled with Poly Clens, agitating it for about half a minute or so. After the flux has been removed he rinses it with water, pats it dry, then ensures the board is moisture-free with a few passes of his heat gun.

He says that the entire process takes him less than 5 minutes per board, which is far better than the old alcohol and stiff brush method he used in the past.

What tips or tricks do you have for getting your new projects cleaned up? Be sure to share them with us in the comments.

Easy to build rig prevents reflow soldering mishaps


[Erich aka VK5HSE] performs quite a bit of solder reflow work, but has always been concerned about bumping his circuit boards once the solder has liquified and is ready to be removed from the heat source. He says that removing workpieces from toaster ovens often results in the unintentional jarring of a circuit board full of components sitting on molten solder, and he wanted to find a solution.

Using some off-the shelf components from a local hardware store, he built a rig that fits on top of a hot plate, allowing him to move hot circuit boards away from the heat source in a smooth controlled motion. The rig is pretty simple, not only preventing unwanted workpiece movement, but also making it easy to regulate the amount of time a circuit board is allowed to heat.

He suggests that his design is not absolutely ideal, and that it can easily be improved upon in several ways without adding significant cost to the project.

Solar monsters… you know… for kids!

Teaching kids to solder using kits is a fun time, but most of these beginner kits are a bit mundane. Not this one, it’s a solar-powered monster project. The components and their wiring connections are printed on a sheet of paper along with a background for that particular monster. The base of the paper is glued to a block of wood and at each solder junction there’s a copper nail. This way the kids can line up the components, check the picture to make sure the polarization is correct for each, then solder onto the large and stable nail head. As you can see in the video after the break, when the solar cell collects enough electricity the transistor triggers a motor to spin the monster.

But don’t get the idea that kits are only for kids. If you haven’t tried your hand with SMD soldering yet, this kit is for you.

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DIY clamp helps with surface mount soldering

Hackaday writer [Gerrit Coetzee] built a simple clamp to aid in surface mount component soldering. This cheap, easily made device uses gravity to hold tiny components in place. The tip of the bolt is pointed, but gently like a ballpoint pen so as not to harm the components with a sharp tip. Roughly position your component, rest the tip of the clamp on its center, then nudge for final positioning. [Gerrit] also points out that this acts as a heat sink, helping to prevent damage to the component if you’re too lethargic with the soldering iron.

It seems like this device has been around in one form or another for quite a long time. But the best ideas do keep on popping up. Another nice tip to go along with this one is the use of a dowel when ironing during toner transfer for your PCBs.

Programmable Game Boy cartridge walk through

We looked at [Gerry's] PLCC based programmable Game Boy cartridge back in May and mentioned that he was working on a how-to video. He did quite a bit more than that. He’s made a PDF version of the instructions but went into deep detail with a collection of four videos on his YouTube channel. We’ve embedded all four after the break. They include an introduction and background about the cartridges, desoldering the ROM chip, preparing sockets and wire, and making the solder connections. Whether you’re interested in this particular hack or not, seeing [Gerry's] soldering practices make the videos worth watching.

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