Homebrew Not A Hakko

We don’t know if [Marius Taciuc] was thinking about how all Jedi make their own lightsabers as a rite of passage, but he decided that it was time to build his own soldering iron. He used a Hakko T12 tip which has a built-in thermocouple. However, he found that the information on the Internet about the tips was either incomplete or incorrect. Naturally, he figured it out and you can see the completed iron in the video, below.

The problem stems from the thermocouple type. Some sites he found identified it as a type K device. Others said it wasn’t, but didn’t say what kind it was. He took a container of oil and heated it to various temperatures and then measured it with both a commercial soldering iron and the T12 tip. By plotting the data against known thermocouple curves, he concluded the device was actually type C.

The custom iron had a few design goals:

  • Very small
  • External power from 9 to 30V
  • Small LCD display with backlight
  • Rotary encoder menu
  • T12 tips
  • Monitor movement to manage standby temperature
  • PCB temperature readings to shut down in case of overheating
  • Audio warnings and alarms
  • Statistics available on the screen

As you can see from the video below he made his goals and it looks like the iron works well. We’ve noticed a theme of taking high-end soldering iron components and pairing them with less expensive homebrew parts. This recent JBC build comes to mind. We’ve even seen other Hakko builds.

9 thoughts on “Homebrew Not A Hakko

  1. Indeed it wasn’t the editor’s fault. It was a weird coincidence. I didn’t knew they were about to publish it and I just made some adjustments to the youtube video like 2 minutes before this article was published. :)) Sorry for this and thanks for fixing the link.

  2. Everything about “today” wows me… After years of through the hole components, except for some 3GHz SM Xistors and caps… and 100w soldering stations. Jewelers’ loupes were not uncommon but only a few binoc-microscopes. And I was usually in R&D.

    Nice Job on the non-Hakko, Marius!

  3. I bought one of those Hakko knockoffs (938D IIRC) for like 65 Euros years ago. It worked on SMD parts or small tracks but any attempt to tin wider tracks or solder bigger leads would require some long time even at maximum temperature to avoid horrible cold joints. I thought it was the stylus or the heater and swapped them both but the problem persisted. The iron wasn’t defective, simply the heater and the tip were not tightly coupled enough plus the tip itself had not enough thermal mass to counteract the instant loss of temperature when touching bigger tracks. Ironically, all those problems didn’t exist when men were men and we used those heavy gun shaped irons decades back: they had perfect coupling between heater and tip because the heater was the tip itself. Good ol’ times!
    Back to the iron, I rarely do SMD and having already tools for soldering smaller parts such a weak iron was of no use to me so I gave it away and went back to an older iron while deciding what would come next. Then one day I saw an used Weller WCTPS at a very convenient price, gave it a try and it was instant love; then ordered some tips from Germany and that’s it.
    So keep in mind those limitations if you decide to build a controller for those styluses.

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