Results tagged “Soldering”

When I tried to solder IC components for the first time one of the mistakes I made was that I did not use solder flux during soldering. The results (inevitable failure) can be read in the correstponding blog post.

Nevertheless when I tried to find out which solder flux to buy I realized that this was a pretty expensive attempt as commercial solder fluxes sell in almost unrecognizable tiny quantities at extremely high prices. Think of something like 10EUR for just 10ml and then this stuff is often extremely poisonous and should only be handled with good ventilation. The one I had a look at initially had three pages of health-instructions in its data-sheet. Inspiring confidence.

Well, I decided to don't go that route and pick up good old colophony ('rosin') which was the primary flux component for decades. What has been good in electronics 20 years ago should be more than sufficient for my purposes. And it's pretty cheap, I could pick up 20g for just 2EUR. I tried soldering SMD again using colophony and of course that time was a success (granted, also using a clean solder tip that time). But it was a bit cumbersome as colophony is in cristaline form and I had to scratch a bit of it for usage which also involved tiny bits and pieces flying off in all directions.

So I decided to take a hint from somewhere (don't remember where), solve it into some isopropyl alcohol and fill it into a small flask with a pipette I still had at home from some overdue nosedrops. This should make a decent selfmade liquid solder flux for hobby purposes. Picking up IPA was no problem, I got 100ml for 3.85EUR at the local drugstore.

From Homemade liquid solder-flux
From Homemade liquid solder-flux

Then I scratched up a larger portion of the colophony so that it was in tiny chips and dust...

From Homemade liquid solder-flux

...and poured it into the flask which was half-filled with the IPA. The larger parts of the colophony took some time to dissolve (barely visible in the photo). I added colophony until the solution had a viscosity which was good to use on PCB.

From Homemade liquid solder-flux

Using a drop of this solution on the IC pins before soldering worked like a charm and I was able to solder the IC onto the PCB without much hassle (can be seen in my first test posting).

One note though, the usage of colophony leaves back some light brownish residues after solding. Those are completely inert, do not interfere with the circuit and cause no harm. To the contrary it has even a certain conservation effet. If desired those residues can be removed also with isopropyl alcohol (still got plenty of it left from the purchase, remember?) but I decided to leave it on for the nostalgic effect ;)

Some warning notes: Although colophony is far from being as poisonous as other fluxes, the fumes should not be inhaled and skin contact should be avoided as it can cause allergies. Make sure the soldering place is properly ventilated and do not touch the fluids. If it comes onto your skin, wash it off with lots of water and soap.


As I've already hinted on in the past weeks I've tackled and completed one of my planned mini-projects.

I assembled the Ice Tube Clock from Adafruit Industries:

From Building Ice Tube Clock
This kit has been on my list for some time now, I stumbled over it on the internet two or three years ago and since that time I regularly checked if it was still available. After I finished my university degree the time was due and I ordered it the instant when there was one available at one of the distributors. When it arrived a few weeks later I prepared my soldering stuff and equipment and built it during two nights. As my last soldering has been already quite some while I decided to practice a bit with the [Pi Cobbler][5] which also arrived with the same order.
From Building Ice Tube Clock
When I was comfortable with soldering again it was time to unpack the parts of the clock and check if everything was complete according to the parts list.
From Building Ice Tube Clock
The soldering and building of the clock was pretty straightforward and easy. I carefully read the [build instructions][6] and had no trouble with the bending, soldering and checking the intermediate results. So here are just a few impressions from the build process. I also tried the suggestion to cut the wires of the VFD tube in different lengths, every wire a bit shorter than the preceeding one, before trying to thread them into the connector PCB. I think that this really helped a lot and made it much easier to finish.
From Building Ice Tube Clock

The last final steps could be completed similar to the previous ones. I only had some slight difficulties with the casing because I initially did not recognize the seperate page for the enclosure-assembling on the webpage but puzzled around a bit and eventually built it correctly without instructions. Manuals are for wimps ;)

From Building Ice Tube Clock

Setting the time and date finished off this neat project. Nice :)

A few mini-statistics:

  • 6h effort in two nights
  • 43 parts assembled
  • 1.5m solder needed
  • 1 solder-accident (although easy to fix)

Some possible improvements are still possible. Although I ordered the kit from a distributor in Italy it still contained only an american 9VDC power adapter. In my opinion shippings within Europe could already contain a proper european power adapter to spare the need for a US/EUR converter. Furthermore the assembly instructions on the webpage do not reflect the process 100% accurately but seems a slight bit outdated. For example there has been a change on the layout of the PCB as the capacitors C5 and C6 have a slightly different placement on the board than on the images in the solder instructions. Also the screws and nuts are not made of metal but of black nylon.

In the end I enjoyed this mini-project very much. It's comparable to the experience I had some time ago during finishing my Master thesis, where I had to code some stuff and had the feeling that I missed real deep code-writing at work. I also missed tinkering with stuff and crafting small things. Since finishing the clock I did also some mods for my mother. Enhancing an electronic candle which ran on a single CR 2032 for ~5 days to use two AA's instead, running now the second week on the first cheap pair of batteries and still pretty bright.

Currently I'm already planning my next electronics project. This time I will not take a kit which can be assembled by following instructions. Instead it will be something where I will have to deal with electronics, ICs and integration with my Raspberry Pi. And it will be not something which is build after instructions but will be designed by myself.

But more on that in a later post...