[jb]

It’s not hard but just like any other endeavor, practice makes perfect.

Tools:

Temperature-controlled soldering iron with a fine tip for soldering passives and individual IC pins and a broad or drag tip for soldering multiple IC pins at once. (note 1)

Skinny solder. (note 2)

No-Clean solder flux. (note 3)

Light. (note 4)

Magnification. (note 5)

Watch the video. http://www.youtube.com/watch?v=t06malVew40 or http://www.howardelectronics.com/navigate/videoclips.html (the fourth in the JBC group) (note 6)

My commentary:

Note 1. The goal is to quickly heat the junction being soldered to a temperature just above the melting point of the solder but no higher. For that you need power and control. A 15w soldering pencil may eventually get the junction hot enough but it will take a long time and will likely overcook the IC. I use a 50-watt hand piece with a variety of tips.

Note 2. Skinny solder means each time you touch the solder to the hot joint, less solder will be delivered compared to fat solder. It takes very little solder to join an IC pin to a PCB pad.

Note 3. Flux is the key ingredient for good soldering. It cleans the metal, prevents oxidation, conducts heat to the junction, and promotes proper wetting and wicking. I apply the flux to the pads before placing the component. The sticky flux holds the component in place and, in most cases, eliminates the need to tack-solder the component in place prior to drag soldering.

Note 4. The more the better.

Note 5. I use 5X for general work and higher magnification for inspection.

Note 6. Drag soldering works best if the PCB has a solder mask. Drag soldering on an unmasked PCB often leaves bridges between the pads and the ground plane. Unfortunately, solder mask is a very expensive option when buying one or two PCBs at a time for prototyping. I use a slow-motion drag technique. With the IC sitting on the fluxed pads, I first touch the soldering tip to the solder to pick up a small bit of solder and then touch the tip to the junction between the pin and the pad. The flux sizzles and does its thing and a small amount of solder is wicked into the junction. Repeat for each pin. I use the same technique for passives.

I’m sorry my other contributions to this Circle were not welcome. Adios.

[laserboi]

I'm preparing myself to begin building my first electronics project, which is a chip amp from audiosector.com.  I appreciate the info on soldering as this is the primary aspect of amp building that has held me back form starting the project.  You have added value in my book and I thank you for that.  Does anyone know of a place that sells practice boards that I can work on before I start soldering on my kit's pcb?  Thanks.

Regards,

Pete

[Alan]

Thanks for the tips, jb. You're obviously very knowledgeable, and sharing the knowledge is always appreciated around here. Just keep in mind that many of us are a few steps (or a few miles) behind you. I'm still struggling with a ptp project, might be a while before I try surface mount.

[JoshK]

I learned a tip that seems to work for me.  I've used it for a lot of small diodes,  SM caps, etc.  Solder a tiny bit of solder to one pad.  Then take the component and reflow the solder so that the component sticks to the pad.  Then solder the other joints.  This makes it easier than trying to juggle lots of hands. 

[laserboi]

Where can I buy "no-clean flux?"  I googled the term and found a bunch of websites that do not sell it and one website that just sells flux pens.  Any info would be greatly appreciated.

Pete