[Coco] Its about that day again (soldering)

Zippster zippster278 at gmail.com
Sat Dec 26 10:33:52 EST 2015

My 2¢ on soldering…..  :)

Hotter with less dwell time is the way to go.  Low wattage irons
end up heating the components MUCH more.  And for some things
they’ll never generate enough heat to keep up with dissipation,
large ground plane sections for instance.

One thing I would suggest also is to try a chisel shaped tip on
your soldering iron (2.4mm or so for most stuff).  These give much
better control when applying heat to pads and leads than the
common conical tips on both through-hole and SMT parts.

If you’re going to solder on a regular basis or do more than a few boards,
get a temp controlled iron.  Chinese units (with hot air wand too) are
available cheaply all over eBay.  This will give you more control over

Getting good results boils down to being able to control the temperature,
controlling heat transfer, and the proper use of flux.

Get some flux in the syringe type dispenser, something like Amtech 4300
to keep next to you when working.  This is very useful on through-hole
components, and absolutely necessary for any SMT work.

- Ed

> On Dec 26, 2015, at 8:49 AM, farna at amc-mag.com wrote:
> I've only used a cheap pencil type soldering iron on my CoCo projects -
> $20 or less. For standard ICs and components you can get by with one just
> fine. I've done many repairs and re-packs with just that 45W pencil. A
> 40-60W is what you want. The lower wattage ones take too long to heat
> solder and will try your patience. A guy who used to do a lot of CoCo
> repairs and build a few things for the CoCo told me once there are two
> ways to solder components -- slow and steady or quick and fast (low watt
> pencil or high watt). Some people used 20-25W pencils and swore by them,
> but you have to hold them on the joint for quite a while to soften and
> remove or solder to. A quick touch with a 40-50W and you're done. You'd
> think the higher wattage would be more harmful, but you only touch the
> joint for a second and heat doesn't sink up into the component, solder
> absorbs most. With a lower watt gun you have to hold it to the joint 3-4
> times as long and the component can actually get hotter.
> Sure, a station with a temp controlled iron is better, but if you're just
> doing a little soldering the 40-50W pencil is all you need. I use a manual
> "solder sucker" to de-solder joints when necessary, but remove most ICs
> destructively (cut pins, hold stubs w/needle nose pliers, heat and pull).
> A pencil could lift traces on some of these new boards, but CoCo boards
> are the old thick variety and are pretty robust. You won't have a problem
> with any etched single or double layer board, I wouldn't think. There are
> some home brew boards that have pretty thin coatings that could be a
> problem, but in general if the solder is hot (liquid) enough you won't
> pull a trace. You can tell when it changes color (becomes shiny) that it's
> liquid.
> Here's a good guide:
> http://www.instructables.com/id/How-to-Pick-the-Best-Soldering-Iron/
> Check Amazon for "soldering station". You c an get variable temp pencils
> from around $20 and up. The lowest cost ones just have a high to low or
> numbered setting, no temp associated with the controls. There are a few
> with temps on the dial or digital readouts in the $40-50 range. Of course
> you can spend a lot more! There are even a couple hot air re-work stations
> with pencil and hot air gun under $70. Read reviews, and determine what
> you need and how much you can/want to spend.

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