10 Sep
2011
10 Sep
'11
9:04 a.m.
In the UK one source of low melting point solders, to reduce the working
temperature, is modelling stores, e.g.
http://www.finescale.org.uk/index.php?option=com_virtuemart&Itemid=56
and
http://www.chronos.ltd.uk/acatalog/Engineering_Menu_Carrs_Solders___Flux
es___etc_346.html for 243 224 188 145 .. degC MP.
Martin
-----Original Message-----
From: cctalk-bounces at classiccmp.org
[mailto:cctalk-bounces at classiccmp.org] On Behalf Of Chuck Guzis
Sent: 10 September 2011 16:30
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: Desoldering (Again)
On 10 Sep 2011 at 13:08, Martin Bishop wrote:
Things which will work:
- Pace SX-90 Sodr-X-tractor or similar hi-end tooling
(my experience is that inexpensive and poorly maintained extractors
are useless) The technique is to oversolder the joint, suck it dry
while wiggling the pin with the tool to preclude adhesion to the via's
barrel - a visit to your local wireman (who has the tooling)
I'll add that a temperature-controlled iron is essential for any kind
of repair work; inexpensive irons just generate too much heat and
lead to damage of the PCB.
Another thing to consider is using Chip-Quik (or any similar fusible
alloy) to lower the temperature of the solder holding the IC in
place. This greatly reduces the chance of damage to the PCB traces.
When I'm working at repairing SMT PCBs, CQ is a standard weapon.
--Chuck