At 06:42 PM 6/18/2010, David Duffy (AVD) wrote: >My apologies is this has been discussed recently (I don't recall seeing it). > >I'm looking for recommendations on desoldering stations. I've used hand >held units & an old Weller station before, but they just never seem to >work very well. (poor suction, easily clogged, etc) We mostly use two types of de-soldering station here: homemade units based on Weller DS100 parts and Metcal MX-500DS. The homemade Weller units are OLD - I built them back in the '80s. They each use a small Thomas 2-cylinder diaphragm vacuum pump with timer and are packaged to be portable - the whole unit fits in a metal box about 10" x 12" x 6". Although I built them with the Weller DS100 iron holder (which holds both the de-soldering iron as well a Weller soldering iron, the Weller soldering irons don't get used much these days. We use Metcal stations for most of our soldering. But the Weller de-soldering irons work REALLY well. Most of that is because of the excellent vacuum generated by the Thomas pump and the solenoid valve in the station body. In use, one steps on the foot-switch momentarily to start the pump, which remains running for about 30 seconds after the last step on the switch. Then let go of the switch and put the iron tip over the lead to be de-soldered. Move the iron around in a circle while maintaining VERY little pressure on the board. You don't want to damage the PCB pad and trace. When you see / feel that the component lead is now free (the solder is molten all the way through the plated-through hole), step on the foot-switch again. The pump has been running all this time but now the solenoid in the base of the iron-holder snaps opens and the solder is removed from the joint. I have found that these homemade units work much better than the original Weller DS100 station, which use a Venturi-style vacuum generator. I attribute their excellent performance to the very good vacuum generated by the Thomas pump and the really-quick vacuum rise-time that the solenoid gives to the system. Its FAST - from zero to about 25" Hg in a few (very few) milliseconds. The solder is completely removed before it has a chance to cool from the air-flow. We also use Metcal MX-500DS units. I have real mixed feelings about these units. One one hand, the heater in the Metcal de-soldering tip is the best I've ever seen. They will melt the solder on multi-layer PC boards with solid planes - stuff the Weller iron can't ever hope to touch. But: they use a Venturi-type vacuum generator that pretty close to being useless. The Venturi system is a pain to keep clean and even when its working its best, its not very good. I've got 3 of the Metcal systems and I think that I'm going to convert them to use a central vacuum system. I suspect that I will then have the best of both worlds. I hope to try using the Metcal de-soldering guns with a central vacuum system sometime over the next couple of months. I suspect that it will work REALLY well. The mods are easy: just plug the exhaust port in the Venturi generator (silicone sealant). Then connect the air-supply hose to your constant vacuum source. I have a 1/2HP 2-cylinder air compressor that was originally designed to be used for solder-fume extraction. Its designed to run 24/7 for YEARS with very little maintenance and has really good suction and flow. Its also fairly quiet (its housed in a relatively sound-proof metal box that has "Weller" silk-screened in very large letters on most sides. Yeah - it was designed to be a solder-fume extraction system. But the homemade Weller DS100 type units are going to stay operational until I can't get parts anymore - they work so incredibly well that just I can't justify retiring them. And - Weller parts are really easy to get hold of. I've also used de-soldering systems made by Pace, Hakko and Den-on. The early Pace stuff is just so much rubbish but their more recent gear is useable. I found that I didn't like the Hakko system at all but no longer remember why. We've also got a couple of small hand-held des-oldering units made by the Den-on Instruments Corp. These actually work quite well but both are currently broken. FWIW: the guys in the shop call these units DIC suckers . I've got an old rework system made by OK International (SMT-2000 ??) - before they wised up and purchased Metcal. It seems to use mostly Hakko components and it, too, doesn't work very well. But - I keep it operational just because we never seem to have enough re-work stations here. I've been using Hakko parts (tips, heaters) to keep it going. I have another old (very old) unit called a "Solder Gobbler". I *think* that its made by Air-Vac. It, too, uses a Venturi vacuum generator. But: this unit actually works quite well. I don't use it much, though. Its not very ergonomic and there are a LOT of exposed surfaces that are melted-solder hot. Bottom line: the Metcal heating system used in their soldering and de-soldering irons is second to none. Best I've ever used. But the Venturi-style vacuum generator in the de-soldering gun isn't very good. A new MX-500 system with soldering iron and de-soldering gun will most likely set you back about US $1000 but you can purchase quality used systems off eBay for about 1/3 of that. Note that you need compressed air to power the Venturi vacuum generator. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist