Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev

wrote in message
ups.com...
Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev


If you apply heat and solder to the wire, solder will flow along the wire
and onto the pin, if it's in contact.

Soldamop wick is handy if you need to remove solder.

Hello, Andrew!
You wrote on Wed, 30 Aug 2006 22:09:59 +0100:


AH wrote in message
AH ups.com...
?? Hi,
??
?? Quick newbie soldering question. I need to solder some wires to pins
?? on an SOIC package. I've never soldered something with this small of
?? pin spacing. Is there a trick for first tacking down the wire to the
?? pin before you solder so that it stays in place? Thanks for any tips
??
?? Kev


Clearly the wire needs to be a slightly smaller dia than the pins and
single core, I find it best to "tin" the wire and the pin first and then
holding the wire against the pin just a quick touch with the iron and they
are joined. Of course the mechanical strength of a solder join like this is
a bit questionable so it's advisable to tack the wires down to the board as
well, with silicone or hot melt.


With best regards, 3T39. E-mail:

On 30 Aug 2006 13:40:28 -0700, in sci.electronics.design
wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev
upside down on bluetak


martin

On 30 Aug 2006 13:40:28 -0700, wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev

I used to do it all the time when SMD parts first came out. Invert
the chip and anchor it to a piece of blank PCB with a dob of hot-melt
glue. Then tin the wire and the SMD leg, touch the two together, then
reflow it with just a touch of the iron. Takes longer to write than
do!

Barry Lennox

"Barry Lennox" wrote in message
...
On 30 Aug 2006 13:40:28 -0700, wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev

I used to do it all the time when SMD parts first came out. Invert
the chip and anchor it to a piece of blank PCB with a dob of hot-melt
glue. Then tin the wire and the SMD leg, touch the two together, then
reflow it with just a touch of the iron. Takes longer to write than
do!

Barry Lennox

One slight thing to remember though. When the chip has been placed on the
board upside down, in BluTack or whatever, the pin numbering is back to
front. Oh how many times have I caught myself out on that one ... !!

Arfa

On Wed, 30 Aug 2006 22:58:42 GMT, "Arfa Daily"
wrote:


"Barry Lennox" wrote in message
.. .
On 30 Aug 2006 13:40:28 -0700, wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev

I used to do it all the time when SMD parts first came out. Invert
the chip and anchor it to a piece of blank PCB with a dob of hot-melt
glue. Then tin the wire and the SMD leg, touch the two together, then
reflow it with just a touch of the iron. Takes longer to write than
do!

Barry Lennox

One slight thing to remember though. When the chip has been placed on the
board upside down, in BluTack or whatever, the pin numbering is back to
front. Oh how many times have I caught myself out on that one ... !!

Arfa

Yep, that got me once or twice. But then the first thing I did was to
use a short heavy wire to connect the ground (pin 7 or whatever) to
the PCB. That served as a reminder of what was where. It also helped
hold the chip in place, as the hot-melt can loosen as soldering
proceeds.

On Wed, 30 Aug 2006 22:49:02 +0100, "3T39"
Gave us:

Of course the mechanical strength of a solder join like this is
a bit questionable

Not if one follows the pre-tin operation with a drop of flux
(microdrop) on the wire or pin. Then, the reflow operation is
pristine. Crisp and clean, no caffeine. :-]

On Wed, 30 Aug 2006 22:49:02 +0100, "3T39"
Gave us:

so it's advisable to tack the wires down to the board as
well, with silicone or hot melt.

Best to use teflon "hook-up wire" and Loctite's
"tack-pack" cyano-acrylate adhesives to pin the wire(s) down to
whatever substrate is involved.

On Thu, 31 Aug 2006 10:23:02 +1200, Barry Lennox
Gave us:

On 30 Aug 2006 13:40:28 -0700, wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev

I used to do it all the time when SMD parts first came out. Invert
the chip and anchor it to a piece of blank PCB with a dob of hot-melt
glue. Then tin the wire and the SMD leg, touch the two together, then
reflow it with just a touch of the iron. Takes longer to write than
do!


Flux is your friend.

On Thu, 31 Aug 2006 12:43:45 +1200, Barry Lennox
Gave us:

On Wed, 30 Aug 2006 22:58:42 GMT, "Arfa Daily"
wrote:


"Barry Lennox" wrote in message
. ..
On 30 Aug 2006 13:40:28 -0700, wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev

I used to do it all the time when SMD parts first came out. Invert
the chip and anchor it to a piece of blank PCB with a dob of hot-melt
glue. Then tin the wire and the SMD leg, touch the two together, then
reflow it with just a touch of the iron. Takes longer to write than
do!

Barry Lennox

One slight thing to remember though. When the chip has been placed on the
board upside down, in BluTack or whatever, the pin numbering is back to
front. Oh how many times have I caught myself out on that one ... !!

Arfa

Yep, that got me once or twice. But then the first thing I did was to
use a short heavy wire to connect the ground (pin 7 or whatever) to
the PCB. That served as a reminder of what was where. It also helped
hold the chip in place, as the hot-melt can loosen as soldering
proceeds.

If you are adding that much heat to a chip while soldering on simple
hook up wires, your are already outside the box from a proto builder
POV. Very bad technique to say the least.

wrote:
I need to solder some wires to pins
on an SOIC package.

Blu-tack the IC to the bench. Tin the lead and the end of the wire. Hold
the wire in place with tweezers, dab, steady hands, job done.

And stay sober the night before.

Paul Burke

On 30 Aug 2006 13:40:28 -0700, wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev


You can also get some handy tips from Wes Hayward's pages at
http://users.easystreet.com/w7zoi/bboard.html

Barry Lennox

wrote:
Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev

It might help if you bend alternate pins up and down.

I'd just make a PCB - much easier

Leon

"Barry Lennox" skrev i en meddelelse
...
On 30 Aug 2006 13:40:28 -0700, wrote:


I used to do it all the time when SMD parts first came out. Invert
the chip and anchor it to a piece of blank PCB with a dob of hot-melt
glue. Then tin the wire and the SMD leg, touch the two together, then
reflow it with just a touch of the iron. Takes longer to write than
do!

3M (i think) had some self-adhesive pads with SMD layouts taken out to the
nomal 0.1" spacing and power strips e.t.c. It worked surprisingly well with
a piece of plain pcb as the substrate and ground plane. Now it's so easy to
run a PCB that I do not bother with anything else for prototyping.

I find that using a stereo microscope makes the process a breeze. I use
the needle point tip in a 15W Antex soldering Iron. The solder
diameter I use is 0.015" and follow the technique explained in other
postings. To hold the chip while soldering, I use double sided tape but
any of the other methods explained should work well.

wrote:

Hi,

Quick newbie soldering question. I need to solder some wires to pins
on an SOIC package. I've never soldered something with this small of
pin spacing. Is there a trick for first tacking down the wire to the
pin before you solder so that it stays in place? Thanks for any tips

Kev