hall effect switch?

[Snoopz]

I used to do these kinds of solder joints all the time while working on embedded software („let’s just unemotionally take a measurement“). Several key insights:

• Get your workpiece fixed (jewellers vise, clamps, glue…)
• Get the right tip for your soldering iron. Resist the initial urge to pick a tiny round tip as it cannot transfer heat fast enough. I have good experience with chisel-type tips. The tip may be larger than the part you are trying to solder, but not overly large such that you solder all pins of your device at once, unless that is exactly what you’re trying to do. 1-2mm is fine even four soldering wires to chips as @dak showed in his video above
• Get flux paste and use it if necessary
• Solder with lead is illegal in commercial applications but makes soldering in a hobby shop so much easier
• Pick solder of the appropriate diameter/gauge if you have several available
• A magnifying glass (I had one of those desk lamp type ones - leaves your hands free) and good light is very important
• And of course: lots and lots of practice

 

[JKJ]

The only solder wick I could find locally was too big,

On soldering and unsoldering… (I realize this is not an electronics forum but someone may be interested)

I do a lot of electronic repair and some design and construction. This morning’s task is replacing three tiny wires soldered into a circuit board inside a small video camera module.

For future reference: I keep a variety of solder wick but I rarely use it. I far prefer a “solder sucker”, a manually operated spring-loaded vacuum device with a tiny nozzle: press the plunger to compress the spring, heat the spot, then quickly move the soldering tip out of the way, put the solder sucker tip close, and press the trigger. This creates a powerful local vacuum and can not only remove solder from a pad but can even suck the solder out of a hole in a pc board holding a component lead or the end of a tiny wire. My geeky friends all rely on these.

A solder sucker is especially handy when desoldering components with multiple leads. Solder suckers are available from electronic supply houses and even from amazon.

Another thing is to have the right soldering iron and tip. Even if you only need one occasionally, I think it’s worth investing in a good temperature-controlled soldering station. I have several, an old one from the ‘60s relies on a magnet in the tip to control the temperature - still works well today. My favorite is a newer one, https://www.amazon.com/gp/product/B000BRC2XU, still over 10 years old (I see I paid only $73 for this model in 2013). But there good digital soldering stations available today for a lot cheaper and they may be better. If you stick to a good brand like Weller you can’t go wrong.

Get a variety of tip sizes, especially very a fine tip. Once I even filed a soldering tip to a needle point to tiny solder wires deep into a well on the back of a digital watch, new at the time (this was long ago, in 1975). I use solder of different diameters too - my finest for delicate work is almost as thin as a cotton thread. And for electronics never, ever use solder made for plumbing.

I’d also recommend practicing a lot on things that don’t matter. I got much of my practice while building computers from scratch in the ‘70’s, from discrete components, not sticking together pre-built components. (One type of memory card I used required 1434 solder connections!) Or ask for help: after fixing a few things recently for one friend, she asked me for soldering lessons. It’s not really hard to do right, just requires learning to get the “feel” for the amount of heat required - you need JUST the right amount of heat, not too much, not too little.

Another option if you don’t solder often - find someone local who will be glad to help! A local makers club might be a good source, or contact a science or engineering teacher who mentors students in things like robotics competitions - they are all over the country.

BTW, I save one old soldering station just for repairing plastic things. I melt the plastic and push it together if needed. Often I cut some small slivers of the same type of plastic from somewhere on the object where it won’t be missed and use it as filler to “weld” the break. The last thing I fixed like this was a hole in a plastic windshield washer fluid tank on a friend’s old truck. Still holding fluid after two years.

JKJ

 

[Ventura]

since it's being discussed in a couple threads..

any parts of any kind that have never yet been soldered..
what helps a lot is to "tin" the leads, and tin the wire.

that means before you try to solder them together,
hit the spots on the jack or whatever with your soldering gun
just enough to get a touch of solder to flow onto them

strip and twist stranded wire tightly, touch the soldering iron to the
middle and stroke toward the end as you touch it with solder
plating the wire.. even solid wires are helped by tinning them..

the solder should flow nicely on or in once the heat is just right,
it has a nice little shine to it when it is perfect, and looks dull if it
wasn't quite hot enough.. just a touch is all it takes,
you don't need to overload the wire making it thicker
or too stiff, or clogging up the little hole in the part

once both things are "tinned" you only need to heat the SOLDER
enough to get them to catch/flow/stick together, reducing the
overheating risk of harming adjacent sections

when you stick bare stuff together without tinning first, you have to
heat both pieces deeply, because the bare metal is first a heat sink
and it takes a bit extra to make the spot you touch with the solder
actually hot enough to pull the solder, and by that time the
wire is smoking or the plastic is melting then something leans over
and ends up distorted or shorting out or you just fry some IC
from the heat

there are also, for things like transistors that have those long legs,
little aluminum clips (like a skinny small spring closepin) that you
clip on the leg above where you intend to solder. This acts as a heat
sink diverting the excess heat into the clip and away froom the body
of the component.. really small lightweight forceps can work too,
but are usually steel and heavier

if a part you are replacing is heavily soldered in place, if you
can disconnect the section of circuit board completely, you
can often heat the lump of solder and flick it toward the cement
floor and much of the solder will fly off, then use de-soldering
braid/wick to clean the rest off. a nice steel needle in a handle
or filed thin and pointy nail can push the hole in the circuit board
open for you once most of the solder is flicked off with just a touch
of heat

 

[Glug]

I've got a background in ham radio and DIY computers too

One thing worth noting is if you get a modern temperature controlled soldering iron they tend to come in two temperature ranges.
If you get the ones starting around 90C you can then also use it for waxing, which will need around 110C.
Here's the one I got 4 years back (when it was cheaper): https://www.amazon.co.uk/gp/product/B07X3CZ3FJ/ref=ppx_yo_dt_b_search_asin_title


And here's my waxing adaptor (modified female spade connector):

 

[JKJ]

I meant to mention magnifiers for soldering. After doing some delicate repair today on the tiny video camera circuit board today I took a pic of two of the tools I used:



The thing on the right has two alligator clips and a magnifier to hold small things while soldering. I also use another one, similar, but it has only the articulated clips and no magnifier for those cases where the magnifier is not needed or might be in the way. These things are inexpensive.

In the center is hands-down the best head/mounted magnifier I’ve ever had, nice working distance, a built-in light, and five interchangeable stereo lenses. Extremely light weight. I have 3 others types I haven’t touched since getting this one. The friend who gave it to me uses them for delicate, precision wood carving and texturing.

JKJ