Through-hole desoldering (was Re: IBM 5110 - Where does the character set live? And other questions.)

Eric Smith spacewar at gmail.com
Thu Jul 13 02:31:32 CDT 2017


On Wed, Jul 12, 2017 at 8:38 PM, Robert via cctalk <cctalk at classiccmp.org>
wrote:

> Side note: It's probably not a good time to try out my shiny new heat
> gun that I've never yet used. Maybe save my first go on it for
> something more replaceable.
>

A heat gun is definitely NOT the right tool for desoldering through-hole
parts, especially DIP ICs.

If you're not intending to reuse a DIP IC, cut the leads off before
desoldering.  Cut the leads close to the package body, not close to the PCB.

Some people say solder wick is good enough for desoldering DIP ICs, but
I've never been satisfied with it. Maybe my technique is faulty. I've had
best results with vacuum desoldering equipment. In order of my preference:

1) vacuum desoldering station with pencil tool: I use a Hakko 472D-01,
which sadly is discontinued. Last fall I accidentally installed a DIN 41612
96-pin connector on the wrong side of a board, and had already soldered
more than half of the pins before noticing the error. It only took me a few
minutes with the Hakko to desolder the pins. The connector and board were
very clean, so I was able to reinstall the same connector on the correct
side of the board. When I purchased it, the Hakko 472D-01 was around $500;
the replacement is the FR410-03 which has better specs (mostly higher power
at 140W vs 110W) but is nearly $1000.

2) vacuum desoldering gun: lots of people liked the Hakko 808, but it's
discontiued. The Hakko FR-300 looks like a reasonable replacement, and
sells for around $310. The drawback compared to the vacuum desoldering
station with pencil tool is that the handpiece is much heavier and bulkier
since it contains the vacuum pump; this is probably not an issue if you
don't use it to do a lot of desoldering in a single session.

3) desoldering pencil with a built-in manual piston-operated pump; I use
one from Paladin, but they seem to have discontinued it, though there are
many similar ones such as:
    http://www.mcmelectronics.com/product/21-8240

4) soldering iron with separate manual piston-operated pump - you have to
be quick switching from soldering iron to pump

5) soldering iron with separate squeeze-bulb - in my experience a bulb just
doesn't work as well as a piston-operated pump

6) soldering iron with built-in squeeze-bulb - same bulb issue as #5, but
even more awkward to handle

Of course, YMMV.

There are also vacuum desoldering stations that use "shop air" to derive
the vacuum, rather than having an internal pump. I've never used them as I
don't normally have an air compressor anywhere near my electronics
workbench.

Since there is a lot less through-hole production now than in the past,
some of the soldering equipment companies that formerly made vacuum
desoldering equipment have abandoned that market segment.


More information about the cctech mailing list