An embarrassing confession

[charliecoutas]

Getting a bit more confident using surface mount chips, I used a couple of tiny Programmable Gain Amplifier chips which had tiny spacing between pins. I bought a bottle of liquid flux, put on two pairs of glasses and took a deep breath.

It didn't go that well, the flux was very thin, smelled funny and didn't do what I expected. It was later, while looking for my bottle of acetone to remove a sticky label that I realised what I'd done!

Using flux instead of acetone gave a much better result.

Live and learn, or perhaps, don't learn.
Charlie

[ricardourio]

If it works, it's as good as a soldering machine
I don't work with SMD every day, but once I understood that with a good flux I can solder all the pins at the same time, it became easier. Sometimes I solder corner pins first. You can preheat the printed circuit board using a hot air station.

Ricardo Urio

[SeanG_65]

Sounds like the electronics equivalent of spraying shaving foam under your arms instead of deodorant the morning after a heavy session.

[John Drew]

G'day Charlie,
When I was a kid I cleaned my teeth with Brylcream once
For those who don't know the product it came in a tube like toothpaste and was meant to slick down hair. Whoops.
How fashions change, oily hair isn't the thing anymore.
It took me ages to get the taste of the Brylcream out of my mouth.
John

[top204]

I made a similar mistake with flux Charlie. I used to think flux was flux, so I used dad's plumbers liquid flux on a circuit board. Then when I powered up the circuit, nothing worked at all, and things were getting hot!

It turns out that plumbers flux has zinc in it, and some have other metal compounds in them, so when it dried, it left a conductive residue all over the board. Hence the shorts and heat. :-)

John. I still remember going to a jumble sale when I was about 6 years old and getting my dad a partial tub of Brylcream. At that age, my dad was "perfect" to his little boy's eyes, and I did not actually see that he had very little hair and had a huge bald patch. :-) But he did not mind, and the Brylcream stayed in his wardrobe until he passed away. It's strange what we remember. I used to have naturally greasy hair as a young-un, because it was down to my shoulders and I hated washing it.

I did get it cut eventually, when I was sitting in the corner of the classroom at about 15 years old with my head turned away from the front, talking to a friend behind me, and a new teacher said "Will that girl in the corner turn around" :-O I had it cut the next week. LOL

[charliecoutas]

There's one thing that goes very well with Brylcream and that's Old Spice aftershave! Along with a pint of Brown and Mild.

Charlie

[John Drew]

I'd forgotten about Old Spice aftershave Charlie. It used to sting like crazy!
@Les A lovely story about you and your Dad, it spoke much about how families should be. Unfortunately there are so many dysfunctional ones in recent times.
John

[JonW]

Clear flux liquid is the best, followed by cleaning with IPA and cotton earbuds. For a scrubber, IPA and a 10mm thick bristled paintbrush with bristles cut to 3 or 4mm are really good. If you order PCB from JLC you can buy a stencil for next to nothing and get some solder paste and squijee it on.  Then pop your parts on and either use a hot air pencil or a hot plate.  Hot plates used to be really expensive but small ones are less than £20 and a 150mm one £65 on amazon.

If time permits for a few off, I always use the JLC SMT process as it's free and really good. 

 

[top204]

Old spice was for granda's when I was a young-un. :-) For me it was Brut or Hai-Karate. Mainly because they were cheap :-)

They also stung like crazy, especially hai-karate. The woman in the hai-karate adverts in the 1970s was absolutely lovely, with huge boobies. Just what a pubescent boy dreamed of. :-)

[charliecoutas]

I fell in love with Julie Christie in the 1970s. She was in a TV series called A For Andromeda. It was a story written by Fred Hoyle, the well known astronomer. An alien signal is received from space, to build a super computer. Ha!

Charlie

[JonW]

Hi karate OMG like brut 33.  That's just raw ethanol, cheaper than IPA haha

[charliecoutas]

Following Jonw's remarks about cleaning pcbs: I use IPA but it always leaves a slight filmy residue. I was nervous of "scrubbing" but I'll give the sawn-off paintbrush a try.

Charlie

[rick.curl]

I recently learned a trick for cleaning PCB's.  I put the PCB in a zip-lock sandwich bag with a little bit of acetone. Then I drop the bag in my ultrasonic cleaner which is filled with water. This saves a lot of solvent but still cleans the boards very well.  You could also use IPA instead of acetone if you prefer. 

-Rick

[John Lawton]

Hi Rick,

neat, but there could be issues with immersion cleaning like this for instance if you have connectors or switches that unless sealed off can get coated in dissolved flux and become problematic.

John

[top204]

Throughout my many years as a TV/Video/Satellite/Hi-Fi engineer, and my career of designing and building PCBs, I have always used an alchohol method. With the general repairs, it was methylated spirits, then I went on to IPA because it became generally available at a decent price. But there is nothing wrong with meths, just do not be tempted to drink it between boards. :-)

However, you must always use a nice stiff little brush, and wipe the PCB several times with the alchohol on the brush, and each time, wipe the brush on some kitchen towel to remove any residue or dirt from it, otherwise you just wipe the crap back onto the PCB. :-) I always found a white brush better, so you can see when it needs cleaning or replacing itself.

[charliecoutas]

Good advice Les. I generally find that alcohol helps with many aspects of life.

Charlie