We’re kind of surprised we haven’t covered this concept before since it only uses techniques that are commonly avaialable for home PCB fabrication. [Ray] made this solder paste stencil out of a sheet of copper using the same etching techniques you would for a circuit board. He designed and printed a resist pattern, with toner everywhere except the places where there should be holes in the stencil. He transferred the toner to the copper using an iron.

The difference here should be obvious; this a thin copper sheet with no substrate. Because of that, you must protect the copper surface before etching. he covered the entire thing, both sides, in packing tape. After that it’s into the Cupric Chloride bath to dissolve the exposed parts. Once the tape and toner has been removed you can scree a precise amount of solder paste onto your boards.

This isn’t for everyone, but if you’re assembling many boards it’s not a bad approach. If the stencil is no longer used it can be recycled, but we do wonder how corrosion on the copper will affect the stencil’s performance.

The idea for this technique came to [Ray] from a guide that’s been around for years.

[Eberhard] wanted his own reflow oven but didn’t really want to mess around with the internals that control the heating element. He put his microcontroller programming experience to work and came up with an add-on module that controls the oven by switching the mains power.

The image above shows a board in the midst of the reflow process. If you’re not familiar, solder paste usually comes with a recommended heat curve for properly melting the slurry. [Eberhard] managed to fit three of these temperature profiles into his firmware.

The ATtiny45 which makes up the controller samples oven temperature via the thermistor seen next to the board. A PID algorithm is used to calculate when to switch mains power on and off via a relay. One button and one LED make up the controller’s user interface for scrolling through the three preprogrammed temperature profiles.

It looks like it works great, see for yourself in the clip after the break.

[Jack Gassett] is developing a new breakout board for an FPGA. The chip comes in a ball grid array (BGA) package which is notoriously difficult to solder reliably. Since he’s still in development, the test boards are being assembled in his basement. Of the first lot of four boards, only one is functional. So he’s setting out to rework the bad boards and we came along for the ride.

To reflow the surface mount components he picked up a cheap pancake griddle. The first thing [Jack] does is to heat up the board for about two minutes, then pluck off the FPGA and the FTDI chips using a vacuum tweezers. Next, the board gets a good cleaning with the help of a flux pen, some solder wick, and a regular soldering iron. Once clean, he hits the pads with solder paste from a syringe and begins the soldering process. BGA packages and the solder paste itself usually have manufacturer recommended time and temperature guidelines. [Jack] is following these profiles using the griddle’s temperature controller knob and the timer on an Android phone. In the video after the break you can see that he adjusts the timing based on gut reaction to what is going on with the solder. After cleaning up some solder bridges on the FTDI chip he tested it again and it works!

Get out the soldering iron and clear your schedule, it’s going to take you a while to assemble this 8x8x8 LED matrix which contains a total of 512 LEDs. We’ve looked in on a 3x3x3 cube, and [Chr], who is responsible for this one, has assembled a 4x4x4 cube before, but this one is quite a leap in complexity. It isn’t just physical assembly problems that increase with scale, you’ll need to consider a power supply too since one layer of a 3x3x3 cube would need at 90 mA, but a single layer of the cube above requires 640 mA to light all of the diodes. Multiplexing is handled per-layer, controlled by  ICs which share 8 data lines and are latched by a shift register. This means the display only requires 11 microcontroller pins for addressing. It is striking how well [Chr] explains the design process, and how cleanly he builds the driver circuits on protoboard. There’s a lot to look at and a lot to learn, not to mention the stunning results which can be seen in the video after the break.

[Thanks Vadim]

Ditch that old toaster oven and move to the next level of surface mount soldering with this vapor phase reflow method. [Ing.Büro R.Tschaggelar] put together this apparatus to use vapor phase reflow at his bench instead of sending out his smaller projects for assembly. It uses the heating element from an electric tea kettle to boil Galden HT 230 inside of a Pyrex beaker. There’s a copper heat break part way up the beaker to condense the chemical and keep it from escaping. When a populated board is lowered into the heated chamber, the solder paste reflows without the need to stress the components with unnecessary heat. Better than traditional reflow? At this level it’s hard to say, but we do find his method quite interesting.

[Thanks Chris]

The application of Solder Paste is an essential part of short run manufacturing and prototyping. After getting back bare boards from a PCB shop, its time to get down to business and populate those boards. This new tutorial set assumes you have access to things such as stencils for your boards, but does mention a couple of resources on commercially available ways to purchase stencils. Of course, if you have a laser cutter, we can help you out. After getting your solder paste chops down, make sure you check out our guide to toaster oven reflowing.

[Thanks to P. Torrone]

Take a few minutes to watch this amazingly informative video on how to solder QFN or MLF components without solder paste.  The quality of the video and the information within is quite nice. Even if you don’t intend to work with these parts, you could pick up some tips for soldering with hot air.

[Luciano] didn’t want to drop a lot of cash into a flux and solder paste applicator so he built his own for about $5. He re-purposed a hot glue gun which you can usually find at a dollar store. After removing the heating element he inserted the body of a syringe. The plunger has been modified to use a knitting needle inside of some plastic tubing. After taking the picture above he made an improvement by adding a milliliter scale to the plunger, allowing you to meter out the paste and also gauge how much remains.

Do you have access to a laser cutter? If so, you can use [Riley Porter's] method to cut your own solder stencils. He starts with the Eagle files and exports the Dimension and tCream layers to a PDF. That file is then processed using Ghostwriter, Gview, and finally, Corel draw. The result is a 1200dpi file to feed to your Epilog laser. Now you’re ready to stencil on the solder paste and populate the PCB.

[Thanks Travis Goodspeed]

Here’s a project from back in 2001 that might be of interest to some of you. It is a guide on how to build your own hot air pencil for SMD soldering.  He is using a super cheap 45W soldering iron from “the shack” combined with a pump type desoldering tool and an aquarium pump. He says it works pretty well, and we don’t see why it shouldn’t. This is a pretty elegant solution. There are also some more recent versions of this mod, but the idea is basically the same.

[thanks Stuart]

Hot on the heels of our post about reading passwords from EEPROM, [n0th1n6] tipped us off about a similar hack used to resurrect an Eee PC from a bad bios flash. After discovering that a factory repair for a dead bios costs about $200, [CutenaCute_7] took on the challenge herself. She disassembled the computer and desoldered the bios chip from the board. After writing a program to flash the chip using C#, she temporarily soldered jumpers to make sure the flash worked. Looks like this is a zero cost hack, plus the time savings from not having to ship her computer somewhere. Bravo.

[Pelaca] upgraded the RAM on his D-Link DIR-320 router from 32MB to 64MB. This hack is simple enough: swap out the existing RAM chip for another one and change the bios to make use of the upgrade. The actual execution is not that simple because of the pitch of the TSOP II package; you’ll need to bring your mad soldering skills to pull this off.

This reminds us of when upgrading original Xbox RAM to 128MB was all the rage. It involved the same type of hack, adding four memory chips to unpopulated positions on the motherboard. The forums are thick with people complaining that their box not working after a failed upgrade attempt. Hopefully you’ll have better luck.

[Thanks Juan]

So, you hacked your DSI did you? Let me guess, you ran a flash cart. No? You probably added some LEDs then right? No? You must be pretty hard core, did you add a NES controler? No? Well what did you do?

We still have no idea what this guy is doing. But he is doing it very meticulously. We found [Micah Dowty]‘s photo stream on flicker and we were instantly pulled in. He has done some extensive modifications to his DSI. He has spread its innards for all to see and begun hacking. It appears as though most of this is for memory dumps and direct access to the RAM in the unit, but frankly we just want to stare at these pictures.

[John P. Barker] writes up an interesting product called Wire Glue. This conductive adhesive is a paint-on alternative to soldering. At first it seems like a bizarre product but we can think of a few uses. Who hasn’t had a solder joint on a free-formed circuit break? One thing’s for sure, we’d recommend throwing a resistor into that LED circuit he’s working on.

Our reader [Damir] built a home made soldering pot. It can be used to solder and desolder components. To remove a through hole component, the solder side is placed in the bath. Then the component is removed with pliers. It is also possible to solder components, by placing the leads in the molten solder; similar to wave soldering. Another common use is tinning self stripping wire. The insulation of the wire is designed to burn off, allowing the strip and tin phase to be single step. This solder pot would be a nice addition to the hacker’s soldering station we had covered in 2008. For more pictures, check out the photo gallery. In the video embedded below, a transformer is easily removed from a modem.