An update on soldering recommendations, with a video

Some FPGA boards are sold with unsoldered headers. Examples include Tang Nano 9K with Gowin and iCEBreaker V1.0e with Lattice. If we solder headers to the Tang Nano 9K with the pins pointing down, we can use this board with a solderless breadboard:

Another option – we can also solder the pins pointing up:

In this case we can use the Tang Nano 9K board without a solderless breadboard:

In both cases we need to solder the pins, either pointing up or pointing down. To do this, we need a soldering iron. Right now, my favorite iron is TS101, a variant with BC2 solder tip:

Soldering the header pins with TS101 is not difficult. The video below shows the basic movement in soldering a pin:

1. Heat the joint from one side.
2. Add the solder wire from the opposite side.
3. Let the wire melt.
4. Remove the wire.
5. Remove the iron.

The whole thing should take 3 seconds and the proper temperature should be between 300-330 С or 570-630 F for the Sn63/Pb37 solder wire we are using.

 

Same video on YouTube

If you do soldering properly, the solder should form cone-shaped domes.

Make sure you don’t have incomplete joints, blobs or cold joints.

In my previous soldering post I recommended using a Pinecil iron. Pinecil is also a good iron, but I prefer TS101 for two reasons:

1. Pinecil does not hold the tip well, I had to adjust a screw with a screwdriver when I installed the tip.
2. When I use Pinecil for a long time, my finger gets overheated.

At the same time, I like the menu in Pinecil more than that in TS101.

Both TS101 and Pinecil use tips with integrated sensors. Such a feature makes the soldering experience much better compared to my previous soldering stations: Weller WE101 and Hakko FX888DX. Solder melts better, in a more stable fashion, and the process goes faster.

Note that I recommend a package with BC2 tip rather than with B2. I have both and I found that BC2 works better with soldering the headers, it simply transfers the heat better and the joint gets ready momentarily. You can compare: BC2 on the left and B2 on the right:

I also found the iron holder that goes with the kit to be too small, so I recommend buying an additional holder, with the brass wool tip cleaner and a cleaning sponge. Something like YIHUA X-2 should work, although I have a different model:

The next item you need is a solder wire. I use 63-37 Tin Lead Rosin Core Solder Wire (0.6mm 50g) – this solder wire has flux inside which means you do not need an additional flux outside to solder the pin headers we discuss. Some people recommend lead-free solder wire, which is less toxic than tin-lead. I tried it and did not like, it does not melt instantly.

There is also a thicker 0.8 mm wire, I tried this as well, but I prefer 0.6 for the kind of soldering we discuss.

Flux in rosin core solder is not a “no-clean flux”, so it is advised to clean off after the soldering with 90-99% isopropyl alcohol (IPA) and Q-tips:

Tang Nano 9K is sold with headers, which I use when soldering the configuration with the pins down. Those headers do not obstruct the LCD ribbon connection. However when I solder the configuration with the pins up, I prefer to use other headers, with longer pins:

When I solder, I use magnifying glasses with LEDs, they help a lot. For example:

I found a fume extractor to be an essential item. Lead in solder is a health hazard, you don’t want to breathe the fumes:

Getting a heat insulation mat is another good idea:

You will also need pliers to split the headers. Just hold a header with the pliers at the point you want to split and push down a part of the header with another hand:

I also use solderless breadboards to keep in place the items with a header I am about to solder. Some examples:

Tang Nano 9K FPGA board:

INMP441 I2S microphones:

I2S GY-PCM5102 DAC for sound output. Note for this component we have to solder not only the header (SCK, BCK, DIN, LRCK, GND, VIN), but also the soldering bridges: H2L, H1L, H4L, H3L:

 

Dissecting microscope with 20X-30X magnification is not an essential item, but when you are a novice, it helps to check the quality of your soldering:

If you are a novice and want to train yourself how to solder headers to a board, but without using actual expensive components, you can buy some inexpensive protoboards for the training purpose:

Nice soldering!

P.S. I need to add a good recommendation for a lightning to this article. I am using a simple lamp but maybe somebody has a better idea. Please add it in the comments.