Desoldering (Again)

Not only do you require a temperature controlled iron, the bit also needs to be the correct size - which varies with the task creating the additional requirement to either have multiple handpieces or easily exchangeable bits. That said a one size fits all iron for 0.1" DIP work would probably have an ~2 mm bit; not the hapiest compromise : a bit too big for soldering and a bit too small for de-soldering. http://www.rapidonline.com/Tools-Equipment/Antex-TCS-50W-Temperature-Con trolled-Iron-85-0550 cheapest UK TC iron ? http://www.rapidonline.com/Tools-Equipment/Antex-660TC-Soldering-Iron-St ation-85-4750 cheap but OK UK station multiple bits : 1 / 2/ 3 mm (ish) bits are required for soldering DILs, soldering chunky connectors, and warming through solder braid - with Antex this requires separate handpieces or some "brutal" tip changes. http://www.pcb-soldering.co.uk/aoyue-6031-sirocco-fan-type-pcb-work-stat ion-.html cheap and good hot air station which supports Aoyue LF quick change bits in the handpiece : ~8 mm dia nozzle is good for freehand SMD (re)work. An underheater chases the groundplanes away http://www.pcb-soldering.co.uk/aoyue-853a-quartz-infrared-heater.html http://www.pcb-soldering.co.uk/aoyue-2900-soldering-station.html hot stick only option for LF cartridges Useful Aoyue tips : LF-16D - 0.1" and 0.05" hand soldering LF-2BC - 0.1" soldering and light desoldering LF-3BC - heavy desoldering, incl lifting 0603 & 0805 Best entry point : Antex station requires multiple handpieces for rapid bit exchange, Aoyue supports hot bit exchange, ... (no simple answer) Regards Martin -----Original Message----- From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Chuck Guzis Sent: 10 September 2011 23:53 To: General Discussion: On-Topic and Off-Topic Posts Subject: RE: Desoldering (Again) On 10 Sep 2011 at 22:59, Rob Jarratt wrote: Ah, okay--let me be clearer. You need a TC iron if you're going to be doing much repair work. The danger of lifting traces is exacerbated by a non-TC iron. With CQ, I remove SMT devices using the heat from a PAR38 lamp, You don't actually melt the original solder; it dissolves in the fusible alloy as the latter melts. You could probably use a soldering iron with an adjustable temperature control turned down (say, 300F). Cleanup is easy--I use an old toothbrush. There are many very decent irons around selling for a fraction of what my Weller WTCP cost me (on the other hand, it's put in more than 30 years of service and I can still get parts for it). Xytronic and Hakko (as well as Weller) are some brands that are worth considering. Others will have their own suggestions, but the important thing is temperature control. In some cases, this is done as an electronic closed-loop controller; in the case of my Weller, each tip is stamped with a number indicating its temperature. A magnet in the handle closes the heater contacts by being attracted to the alloy slug at the base of the tip. When the alloy reaches its Curie temperature, the magnet is no longer attracted to the tip and the circuit opens. Very old school and very reliable. What others haven't mentioned is that in multilayer boards with power and ground planes, it can be difficult to get enough heat to a joint to melt solder, as the heat is conducted away from the iron tip as fast as it's supplied. CQ comes in handy there, by lowering the melt temperature of the joint. For whatever it's worth, Chuck