[Coco] Sodering Iron

[Andrew]

My 2 cents:

I didn't learn how to solder until after high school, when I left my 
home after graduation to take up residence here in Phoenix, in order to 
attend a local, but now defunct, vocational tech school here.

Each student in the course was "given", in addition to their Grob's 
Basic Electronics textbook, a set of tools and a toolbox; I still have 
most of those tools, including the soldering iron. While I haven't used 
it in a long while, I have no doubt that it works.

I also have no doubt that I could solder with it (at least thru-hole 
parts, which is all I have ever learned - I have yet to learn or need to 
learn SMT soldering - and probably today at my age, I'm not sure I have 
a steady enough hand to do it, let alone the eyesight - ugh).

Today, you could pick up the same or similar soldering iron - a whole 
kit in fact - for less than $20.00 off Amazon. In fact, you might even 
get a better iron in the deal (one maybe with temp control).

It was a 15 watt jobber - plug it in, stick it in the cheap stand (iron 
base with a sponge and a wire spring holder for the iron's business end) 
- and in 15 minutes or so, it was up to temp (it takes much longer to 
cool down).

You really don't need much more than that for basic work with thru-hole 
parts and PCBs.

It had a basic tip on it - not pointed, not "wedge" - but more like a 
thick, yet small, flat tip - like a standard flat screwdriver. Today, 
after the use and abuse I put it thru, both as a student and later, it's 
ugly as sin - but still works fine.

Now - I can give a bunch of tips on "how to learn to solder" - and a 
bunch of "try not or do no do's" as well, and if you want those, email 
me and I can talk your ear off (actually, I encourage you to do this, 
because I do have a lot of hard won thoughts that may help you out), but 
this email is already a new chapter of my biography I'm composing on the 
internet, one post and email at a time...

What I will say, though, is this: You don't need a fancy, super 
expensive kit for soldering. No Hakko, no whatever, no "special" solder, 
no extra rosin, etc.

Just a cheap soldering iron, some basic leaded rosin-core (NOT 
ACID-CORE!!!!) solder, a dry sponge (or better, a cheap ABS pipe cap 
with a non-soaped copper sponge in it - way cheaper than most stuff you 
can buy) for cleaning the tip. If you want some rosin paste, get 
something cheap (it is useful for cleaning the tip, too).

Also pick up a "solder sucker" and some "desoldering braid"...

For the solder, go for 60/40 or 63/37 leaded solder (I prefer the 
latter, as it flows better). Most non-leaded solder needs a higher 
temperature to flow properly, giving you less time to get the part 
soldered properly without lifting pads or creating cold joints - or 
destroying parts with excess heat.

...and certainly don't get "silver solder" unless you're using a very 
high-temp iron and doing jewelry - that's a metal-joining solder, 
mainly...not for electronics, and probably needs a special rosin or 
something to work properly anyhow.

One more important bit: Wear eye protection! DO NOT SKIP THIS. Ideally, 
full goggles, but even a pair of glasses is better than nothing. Be 
prepared to get burned with popping solder (actually, the rosin popping, 
throwing bits of molten solder about).

It will happen when you least expect it, landing on you hands and 
finger, occasionally on your face, hence the eye protection. It will 
hurt (not as bad a molten metal when welding - but not nice, either!). 
Don't jerk and don't drop the iron if you can help it! If you do drop 
the iron, DON'T TRY TO CATCH IT. You will grab the wrong end.

I say this as someone who did just that while learning, so you probably 
will do it at least once in your life. You will not do it again after 
that, unless you're a slow learner. Also - wear closed-toed shoes and 
pants, because having a hot iron land on your leg, lap, foot, etc - none 
of that is good, either. Oh - and don't solder naked, even if you're 
into nudity, as that iron is going to fall where you really don't want 
it to (talk about pain!)...

Finally - gather up a bunch of patience, and find some old broken piece 
of thru-hole electronics to "play with" - something you don't care if 
you ruin or such. An old radio or electronic clock (make sure it isn't a 
"collectible"! You'll kick yourself for destroying something you later 
learn was worth a ton of money - ask me how I know!) - something like 
that. You don't need a "practice kit" - unless you have no other option. 
Save the kit for a later project - what you want to learn is "how to 
solder" and "how to desolder".

The main keys to successful soldering is:

1. Having a clean iron tip - when first starting with a new iron, "tin" 
the tip by (after it is up to temp) melting solder on it, which will 
make it "bright" and cleans it. Dipping it into rosin paste, then 
tinning, can also be done. Clean and tin the tip before you begin, and 
after you stop (before letting it cool down).

2. Don't use a wet sponge if you can avoid it for cleaning the tip (this 
is controversial; last I knew what it does is cause micro-cracking of 
the nickle cladding on the copper of the tip, which eventually leads to 
destruction - this might be more an issue for "production" 
hand-soldering - I'm not sure). Use (as noted before) some kind of 
non-ferrous metal copper or brass sponge (Note: there are such sponges 
out there made of copper-colored plastic - avoid them for obvious reasons).

3. You may need to clean/re-tin the tip as you solder - it will help!

4. Get the part and pad up to proper temperature, so that the solder 
will flow and "wick into" the joint. Don't rush - but don't dilly-dally, 
either. To much time heating the part and pad can lead to destruction of 
the part, and/or "lifting" the pad from the PCB (delamination). A second 
or two is all you need, but you may need a bit more time depending on 
part size, lead size (that is, size of the "wire" on the part you are 
soldering - both act as a "heat sink" that draws heat away from the tip 
and joint).

5. Corollary to #4 - some parts can't be soldered well with a small 
iron, particularly those with thick legs or large wire joints. Consider 
a higher-wattage iron, or some alternative to soldering to join those.

6. Don't let the rosin in the solder burn; it will smoke (see below), 
but when it stops smoking, that means there's no more rosin, and that 
can make creating a good joint difficult. At that point, either desolder 
and re-try, or add a touch more solder, or some rosin. If you are moving 
at the correct speed/cadence, this shouldn't be a problem (again, 
practice makes perfect!).

7. Start with "low and smaller parts" first (those that hug closest to 
the board), with higher (and larger) parts soldered later - it will make 
building a project way easier (most kits will suggest this as the order 
of part assembly/placement).

8. In between each joint, let the soldering iron come back up to temp (a 
few seconds between joints); develop a rhythm (music can help, perhaps).

9. When learning, concentrate on simple parts - like resistors, then 
move to diodes, transistors, then ICs (8 leg simple things like 555 
timers at first). Resistors tend to be fairly forgiving (at "dwell time" 
on the part).

That's the basics - like I said, I can write a book on this, I'm sure.

Oh - and having good ventilation (an open window and/or a fan) is 
worthwhile.

Note: The "fumes" or "smoke" you see from melting solder ARE NOT "lead 
fumes" (for lead to vaporise takes way more heat than you'll be using) - 
they are actually fumes/smoke from the vaporization of the rosin in the 
solder, and pose little to no health-risk. That said, if you have asthma 
or are sensitive you may be affected by them more than others. In any 
case, don't inhale them! They will irritate mucous membranes of the nose 
and throat - so a tiny fan, or working outside, or having an open 
window, etc - good ventilation is important (and if you do a ton of 
soldering, consider buying/building a desktop carbon-filter fume 
extractor). A side note: If you ever use acid-core solder, for metal 
work, pipe work, etc - DO NOT BREATH THE FUMES OR LET THEM CONTACT YOUR 
EYES. Unless you like the feel of acid in your throat or on your 
sensitive bits...

Lastly: Save buying a decent "soldering station" once you know what you 
are doing, and how much you are doing it, and what kind of projects you 
plan to work on. You might find an "el-cheapo" iron is all you need. Or, 
you might want to go for that Hakko or whatnot (variable, quick-heating 
and cooling irons are very useful for dialing in a temperature for 
things like non-leaded soldering and such). Also note that there are 
lower cost options that still use quick heating and cooling heating 
elements (versus the cheapest of irons) that can be had.

Also, stay away from most of the cheap "battery powered" soldering 
irons, and especially that "cold heat" contraption that was sold on TV a 
while back. USB-based irons should also be avoided, as they can destroy 
the USB ports on computers depending on how much current the port can 
supply (even the best only supply maybe a couple of amps, so 10 watts 
are all the iron can output on a good day). If you need a portable 
solution for field work, I can give some suggestions...

I hope you enjoyed my latest chapter - but honestly, this is only the 
beginning of my possible suggestions I could give you. There is more to 
soldering than most "tutorials" online cover, with one of the greatest 
myths being "you need an expensive iron to solder with" - when the truth 
is, you can get away with a piece of metal wire hanger and a butane 
lighter if you're desperate (post-learning and experience, of course).

Andrew L. Ayers
Glendale, Arizona
phoenixgarage.org
github.com/andrew-ayers