Critique my soldering.

[delthebike]

My first foray into fiddly small soldering jobs.
It's a little project for Raspberry Pi.

[Kim]

Mostly looks okay, but it's gone a bit wrong (blobby) on the back of the Rasperry Pi header socket.  Either the board needed a clean (quick rub with wire wool), you should have added flux (shouldn't really have to with this sort of job - becomes more important with fiddly SMD stuff), or you're using lead-free solder without enough heat.

Solder blobs around component legs should be concave, rather than convex.

I expect it'll work fine, though.   


(Good soldering is mostly about practice and the presence of lead, though good temperature control helps.)

[delthebike]

Thanks Kim.
I didn't know about using wire wool on the board. I used a lead solder with a rosin core, 0.7mm, Sn60/Pb40, and a new iron, analogue dial, cranked up to ~400^oC. The blobby 26 pin header was the first bit to get done and the 13 pin header was the last bit.
Just waiting for my next job to arrive, a 40 pin header on a Pi Zero.

[tatanab]

As is said in the trade "the bigger the blob the better the job" - not in a nice way.  As said above, cleaning the areas to solder to would help and a little less solder too.  None of this means it will not work, it just means it is not fit for spacecraft.  I'd say, ok for a beginner.  These days I suffer with normal middle age vision and my soldering is rubbish because I cannot see that closely.

[mrcharly-YHT]

ok for beginning.

The way the solder has flows suggest to me that you held the solder against the iron, or melted it onto the iron then touched the work.

Ideally, you heat up the pins with the iron, then touch the solder to the pin. You can pre-heat the solder to near melting point by holding it near the soldering iron tip.

[Kim]

I used a lead solder with a rosin core, 0.7mm, Sn60/Pb40

Pretty much ideal.

and a new iron, analogue dial, cranked up to ~400^oC.

I'm generally happy at 300C for that sort of work with 60:40, though it will depend somewhat on the iron.

Chisel tip better than the standard conical one, if you've got the option.  It's bulkier, but better at delivering heat to where it's needed.

The blobby 26 pin header was the first bit to get done and the 13 pin header was the last bit.
Just waiting for my next job to arrive, a 40 pin header on a Pi Zero.

Sounds like it's mostly technique then, and you're getting the hang of it with practice.


<a href="http://www.youtube.com/v/fYz5nIHH0iY&rel=1" target="_blank">http://www.youtube.com/v/fYz5nIHH0iY&rel=1</a>
http://youtu.be/fYz5nIHH0iY

Might be worth watching for correct technique.

[delthebike]

mrcharly
I had the pointy tipped iron touching the pin and board then applied the solder. A few/several pins got too much solder and I melted the solder again and tried to carry excess away with the iron and or the solder wire.

tatanab
I'm short sighted and managed with a mark one eyeball without visionary aids.

Kim
Thanks for the video link. I've only got a pointy tip but I'll be getting some other shape tips soon.

[Kim]

I had the pointy tipped iron touching the pin and board then applied the solder. A few/several pins got too much solder and I melted the solder again and tried to carry excess away with the iron and or the solder wire.

Best way to get rid of excess solder is with a solder sucker or wick (depending on fiddliness of the job, so you really want both).  Failing that, heat up the joint and bash the edge of the board against the desk so the blob flies free.  Picking up blobs with the iron isn't going to work particularly well, and attempting to solder them to the end of the new solder is ...well, I can't say I've actually tried it.  Does it even work?


Mk1 eyeball is fine for standard through-hole stuff, but my Mk1 eyeballs are still rated for close up work.  Magnification becomes useful for finer SMD stuff (along with tweezers, forceps, flux pens, silver solder, exotic tips, hot air rework gun, a plentiful supply of solder wick, patience, a modified toaster oven and a seismically stable desk).

Don't worry too much about the pointy tip - it's certainly achievable with one.

[mrcharly-YHT]

You need some solder wick, like Kim said.

Then when you get good at this, you can try lead-free solder <Kim makes retching noises>

Any work on commercial stuff means you have to use the lead-free stuff and it is bloody awful to work with.

[Kim]

My lead-free technique is improving, but the amount of heat required means it still looks like a dog's breakfast afterwards.

I stick to leaded where I can, but it's easier not to mix them when re-working stuff.  I've not been brave enough to attempt anything really fiddly with lead-free.

[noisycrank]

  None of this means it will not work, it just means it is not fit for spacecraft. 

In a discussion with a left-pondian chum about the relative merits of civil service in each country they were relatively impressed with the quality and commitment of the public sector over here. Referring to the expression "good enough for government work" they commented that this was a particular reason they were always impressed by the bravery of Astronauts. In the days when 'merica still had a manned launch capability of course.

[sojournermike]

I was a bit shocked at my last project when I used some new fangled lead free solder forth first time. Eventually settled on 345 degrees iirc for small bits and hotter for big. It really isn't as much a pleasure as watching lead based solder flow, even if everything works fine.

[T42]

It's the smell of the resin that I love.

I have a very light dental magnifier for close work. Perfect - no risk of Shermer's.

[Biggsy]

Just to add explanation to the advice given already:  Too much heating of the solder burns off the flux in it.  That's what the smoke and smell is.

But touching the solder against the iron quickly gets it to start to melt (before moving it over to the component), and a little bit of molton solder on the iron to start with helps a lot with heat transfer, so don't take the advice to never put solder directly on the iron too literally.  It's just that you need to ensure there's fresh flux as well by only indirectly heating the rest of the solder, or by adding extra flux separately, from a flux pen or whatever.  So heat doesn't harm the actual solder, only the flux in it.  Of course excessive heat also damages components

[Kim]

And if you really overcook it, you can start lifting pads from the board.  Relatively unlikely with through-hole stuff, unless you're replacing a connector that's been subject to mechanical stress.

[Biggsy]

I'm particularly prone to lifting pads while de-soldering ...which I sometimes find harder than de-scrambling an egg. 

[Kim]

I do keep wondering whether a proper de-soldering gun would be a worthwhile investment.  Okay, there are plenty of things they can't do - where you'll still have to resort to braid, sacrificial fingers and violence - but it doesn't take many pins on a component/connector before the idea becomes quite attractive.