Oops.. how do I desolder an IN-14 Nixie Tube?

[Mighty Burger]

How do I desolder an IN-14 Nixie Tube from a PCB without destroying the tube?


I'm working on my Nixie Tube clock project. I've assembled everything, and I'm happy to report things seem to be working well apart from a small software bug causing the Nixie pin assignments to be off by 1.
However, I was rushing through assembly, and I ended up soldering three out of the six Nixie Tubes before I remembered I wanted LED's under each tube!

It's not critical, since I think I will end up running the clock with the LEDs disabled. I prefer the raw Nixie glow. However, I want to be able to use this clock to demonstrate my design and use it as a reference for when I make more clocks to sell.

I would like to desolder those three Nixie Tubes, solder in the missing LEDs, then re-solder the Nixie Tubes back onto the board.

Would you all have any advice?

[SeanB]

Hot air, large nozzle, and gentle heating so the glass does not get stressed, and warm up slowly till the solder melts, then pull of the tube gently, and allow to cool slowly.

[Mighty Burger]

Hot air, large nozzle, and gentle heating so the glass does not get stressed, and warm up slowly till the solder melts, then pull of the tube gently, and allow to cool slowly.

Awesome. I recently acquired a hot air station, I didn't think to use it on through-hole parts.

I'm concerned the spacers I've printed out of PLA will melt under the heat however. It might make a bit of a gooey mess.

[Gyro]

As the LEDs are tasteless blue, I wouldn't risk the damage. Just cut the track to the existing LEDs to remove any temptation to turn them on again later. 

[Grandchuck]

https://www.amazon.com/dp/B002MJMXD4?tag=smtinsight-20&linkCode=ogi&th=1&psc=1

[CaptDon]

A nice desoldering station would be helpful. Spend the money, they last forever and will help repair future mistakes.

[Mighty Burger]

I should've taken CaptDon's advice and bought a desoldering station.

I ended up using a hot air reflow station. I was right to be concerned about the PLA melting. Took a while to heat it up enough to where the through-hole joints liquefied. At that point, the PLA spacer was goo, and large strands of plastic stretched out as I pulled the tube from the board. See attached image to get an idea of what I'm talking about. It was an absolute nightmare.

Wiped off as much gunk on the board as I could using IPA, there was still lots of hardened plastic caked on. It was a pain getting the molten spacer off the Nixie tube as well.

I didn't have a 3D printer on hand so I ended up drilling holes in the middle of two of the spacers the tubes came with, and stacking them together to reach the correct height.

Fitting the leads back through the PCB was a serious pain too.

I haven't tested it yet, but I'm concerned throughout all of the mechanical and thermal stress I put on this tube that I've broken it or reduced its lifespan.

Well, at least there's 4 LEDs on there now instead of only 3. There is no way I'm repeating this procedure for the last two Nixies.

[grumpydoc]

Well, at least there's 4 LEDs on there now instead of only 3. There is no way I'm repeating this procedure for the last two Nixies.

Use wick or a vacuum desolder pump to clear out as much solder as possible from each pin, replace with low temp "desoldering" solder eg ChipQuik, use hot air gun as previously but this can now on much lower temp to remove tube.