Super Easy DIY hot air pencil: "Under $20"

You can get a little SMD hot air station for around $100, and I’ve seen a variety of examples of people building their own out of aquarium air pumps and irons, either by drilling out a tip or chucking a piece of metal tubing in the iron, or even just blowing hot air through the exposed heating element. That’s all well and good, but I just spotted this little guy, and now I’m dying to try making one myself:

As I think I’ve mentioned before, I’m a huge fan of the Radio Shack 45-Watt Desoldering iron, I’ve gone through four or five of these guys at this point.

The red bulb tends to wear out after a few months of heavy use, but it just never occurred to me to hook up an air hose to the post, it’s perfect! The iron only costs $11, and you can buy a cheap (loud) air pump for $5, but really, who doesn’t have an old aquarium air pump lying around! The real secret seems to be putting a bit of steel wool into the screw-off tip to increase the surface area of hot metal the air has to go through. Brilliant!

Thinking about hooking up tubing to this guy, I’m a actually more excited with the possibility of making it into a powered solder sucker. It is always a little cumbersome to hold it in place and work the bulb. I imagine I could reverse the check valves on an aquarium pump, then wire up a foot pedal to the power cord. I would probably want to use silicone tubing to cope with sucking high temperature air back through it, and I’m not sure if I would really get enough airflow, but still, it’s totally worth a try!


It may still work well as a hot air blower, but not so much as a solder sucker.

The reversed aquarium pump was pretty weak, but it still did a decent job on the first two or three pins I desoldered with it. The foot-petal was pretty pointless, as I realized I wanted it running all the time. I didn’t think too much about this beforehand, but in hindsight it’s obvious that blowing the last bits of solder out when you squeeze the red bulb is a very important step. The tip/tube was completely clogged with solder after a few more pins, and stopped working completely. As soon as there was no airflow, the silicone airline tubing heated up and split off it’s post.

For the time being I guess I’m just sticking with the little red bulb for sucking, and if I need to do some hot air rework I can always scrounge up another aquarium pump.


to solder with that do you put a little solder on each pad, place the components then use that to rehead the solder and everything melts into place?

That’s one way to do it, it helps to put a little bit of solder on the component leads too. The right way to do it is by using solder paste, a toxic slurry of minuscule powdered solder suspended in liquid flux (in general you should wash your hands after any kind of soldering, especially before eating). You apply it with either in small dabs with a syringe or spread it over a stencil. Then, when you heat it with the hot air, the tiny particles melt and coagulate together, and solidify as they cool. Personally I try to stay away from the stuff whenever I can.

You can do a fair amount of surface-mount soldering with just a very fine point iron tip (and a headband magnifier, and steady hands). Almost all of the hot-air soldering I do is to remove surface-mount components with many leads that have to be heated up simultaneously, aka hot-air rework.