[sdiy] Starting with SMT hand-soldering

[Harry Bissell]

In my case, its the latter (mad two handed technique) I use an iron in each hand to heat both
sides of the component at the same time and lift it off the board, or shove it where it can't stick back again. I also (sometimes) use two irons to 'reflow' two component pads and center an errant component.

I also use solder wick to remove bridges and excess solder from packages too fine to solder
with any reasonable size tip...

H^) harry



----- Original Message -----
From: Adam Schabtach <lists at studionebula.com>
To: 'Synth DIY' <synth-diy at dropmix.xs4all.nl>
Sent: Fri, 29 Oct 2010 11:19:26 -0400 (EDT)
Subject: Re: [sdiy] Starting with SMT hand-soldering

> 1) A couple of you mentioned multiple irons - is that for a variety of
tips
> or is there some mad two handed soldering technique you've got going. No -
> I'm serious.

I considered trying some mad two-handed method, but I have only one good
soldering iron. This is the most inexpensive rework tool I've found on the
market (which isn't to say that I did an exhaustive search):
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_224629_-
1
They're not great but they do work. They're fine for removing 0805 and 1206
resistors and caps. (I tend to use 1206 because I have middle-aged eyes and
1206 is large enough that I can do most work without a magnifier. I use 0805
for decoupling caps since the smaller package is easier to place close to
the power leg of a chip.) The broad tips work fairly well for removing ICs,
although it requires a modicum of patience. You hold the tips against all of
the legs of the chip, wait a few seconds, give a little twist to see whether
the solder has melted. Once it does you just lift it off the board. 

In my experience this tool has only been necessary a couple of times, and
once was when I was modifying an audio interface and had to remove a whole
bunch of 0805 resistors. If you're building stuff and have budgetary
concerns, a package of Chip-Quik is a more economical approach. I did nearly
destroy a PCB by trying to remove a TQFP microcontroller by cutting its
legs, so personally I shy away from that least-expensive approach. (For
perspective, the board I nearly destroyed was worth 2x what a package of
Chip-Quick costs. Also note that the aforementioned hot tweezers won't work
for quad packages.)
 
> 2) Temperature controlled iron - nice if you've got it or vital?

Vital, but I would say that's true for through-hole work also. I don't use a
fancy SMT rig, though--just a Weller WES51 with several sizes of tips. I
used to use a fine chisel-point tip for just about all SMT work, but
recently I've been using a broader chisel tip for drag-soldering IC leads.

--Adam


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-- 
Harry Bissell & Nora Abdullah 4eva