Solder braid: width?

A

aleksa

Guest
I want to solder one TQFP144, but do not have
any experience with anything more than DIP40.

This is what I'm planning to do. I will:

1. apply some tinnol on all the pins on the PCB
2. remove excess tinnol with dump cloth
3. place the chip and solder it pin by pin with solder iron

step 3 will certanly solder several pins together which I plan to
fix with solder braid. The question is: what width should I buy?
 
aleksa wrote:
I want to solder one TQFP144, but do not have
any experience with anything more than DIP40.

This is what I'm planning to do. I will:

1. apply some tinnol on all the pins on the PCB
2. remove excess tinnol with dump cloth
3. place the chip and solder it pin by pin with solder iron

step 3 will certanly solder several pins together which I plan to
fix with solder braid. The question is: what width should I buy?
Click to expand...
Contrary to what Ian and Ben have said (and they're both good guys),
when I have to do this I use the following procedure:

1. Locate the part and tack down opposing pins (i.e. pins
1 and 73) so it sits where it belongs.
2. Solder all the pins on one side. Just drag the iron and
make a big glob of solder across all the pins. Think of
it as the Golden Gate of solder bridges.
3. Wick up the solder (carefully) with some honking big (1/8")
solder wick. Just lay it sideways on that Golden Gate of
solder and suck it all up.

It's fast, it's easy, I'm up to about a dozen parts on various boards
now, and I've never had a problem with it.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html
 
On Thu, 17 Jul 2008 13:19:58 +1000, "Tony Burch" <tony@burched.com.au>
wrote:

"aleksa" <aleksaZR@gmail.com> wrote in message
news:29f3968d-491c-4257-8ad8-d059f77253bd@t54g2000hsg.googlegroups.com...
I want to solder one TQFP144, but do not have
any experience with anything more than DIP40.

This is what I'm planning to do. I will:

1. apply some tinnol on all the pins on the PCB
2. remove excess tinnol with dump cloth
3. place the chip and solder it pin by pin with solder iron

step 3 will certanly solder several pins together which I plan to
fix with solder braid. The question is: what width should I buy?

Hi,

I would not recommend using solder braid. Please have a look at the video at
http://www.supersolderingsecrets.com for a reliable technique for had
soldering TQFPs.

If you don't have a "reservoir tip" for your iron, you can just use a broad
chisel tip.
Click to expand...
For some alternative videos and tutorials (including using braid) that
don't require a "full membership," interested parties may wish to surf
on over to http://www.sparkfun.com/commerce/hdr.php?p=tutorials

Disclaimer: I have no association with Sparkfun other than as a
satisfied customer.

--
Rich Webb Norfolk, VA
 
On Jul 17, 1:10 am, Ben Jackson <b...@ben.com> wrote:
On 2008-07-16, aleksa <aleks...@gmail.com> wrote:



1. apply some tinnol on all the pins on the PCB
2. remove excess tinnol with dump cloth
3. place the chip and solder it pin by pin with solder iron

I'm not sure what 'tinnol' is, but assuming it's some kind of liquid
flux:  Skip step 2.  You can readily solder fine pitch parts like that
in a puddle of flux.  Fine pitch + lots of flux = easy.  In fact, the
first remedy I would suggest for almost any problem (including bridged
pins) is to add flux and reheat it.  You can often "pick up" the excess
solder with the iron and remove it or redistribute it.  With lots of
flux, the solder will strongly prefer to stick to the pins rather than
itself which can cure the bridge.

If you get braid, make it very fine, and NEVER PULL IT OFF THE BOARD
if it resists.  If you do, you will remove traces, bend pins, etc.  It
can help to tin the braid as well, but it will corrode over time.

--
Ben Jackson AD7GD
b...@ben.com>http://www.ben.com/
Click to expand...
'tinnol' = 'solder wire'.

What is liquid flux? SMD solder paste?
Schukat has it, 15EUR for only 10ml of paste.

Maybe it is possible to place the braid across
all the pins (min 3cm), heat the whole braid and
it will pick up all the solder at once? If the
braid is enough heated, it won't break the traces.

BTW, the minimum braid width at Schukat is 0.5mm, max 2mm.
 
In message <2bidnSvCILwiG-PVnZ2dnUVZ_oLinZ2d@web-ster.com>, Tim Wescott
<tim@seemywebsite.com> writes
Contrary to what Ian and Ben have said (and they're both good guys),
when I have to do this I use the following procedure:

1. Locate the part and tack down opposing pins (i.e. pins
1 and 73) so it sits where it belongs.
2. Solder all the pins on one side. Just drag the iron and
make a big glob of solder across all the pins. Think of
it as the Golden Gate of solder bridges.
3. Wick up the solder (carefully) with some honking big (1/8")
solder wick. Just lay it sideways on that Golden Gate of
solder and suck it all up.

It's fast, it's easy, I'm up to about a dozen parts on various boards
now, and I've never had a problem with it.

You and me both, in fact I've used this technique to rework stuff at
Click to expand...
home on plenty of occasions now, the only slight difference is that I
apply a little pressure to the chip package so the pins are pushed
gently onto the pads whilst I solder them on.

I've also used the puddle of solder to remove chips, using a sewing
needle apply a little leverage between the chip body and board, drag the
puddle of solder along the legs away from the needle, move needle to
another corner, rinse and repeat. A little practice and a few cycles of
this will remove chips quite easily with no board damage. Clean up with
wick and flux remover once the chip is off before you attempt to replace
the chip.
--
Clint Sharp
 
aleksa wrote:
I want to solder one TQFP144, but do not have
any experience with anything more than DIP40.

This is what I'm planning to do. I will:

1. apply some tinnol on all the pins on the PCB
2. remove excess tinnol with dump cloth
3. place the chip and solder it pin by pin with solder iron

step 3 will certanly solder several pins together which I plan to
fix with solder braid. The question is: what width should I buy?
I find it very very interesting that NO ONE is talking about the cursed
Click to expand...
Lead-free solder !!! "Long-Live eutectic 65/37"

Yukio YANO
 
Yukio YANO wrote:
aleksa wrote:
I want to solder one TQFP144, but do not have
any experience with anything more than DIP40.

This is what I'm planning to do. I will:

1. apply some tinnol on all the pins on the PCB
2. remove excess tinnol with dump cloth
3. place the chip and solder it pin by pin with solder iron

step 3 will certanly solder several pins together which I plan to
fix with solder braid. The question is: what width should I buy?
I find it very very interesting that NO ONE is talking about the cursed
Lead-free solder !!! "Long-Live eutectic 65/37"

Yukio YANO
sorry "63/37 tin/lead"
Click to expand...
 
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