SuckWell

Projects
Participants	Ultratux
Skills	Soldering, pneumatics, mechanics
Status	Active
Niche	Mechanics
Purpose	Fun

Two decades ago I purchased a Weller® desoldering contraption that is compatible with the venerable WTCP-S soldering stations. It consists of a heated suction tip leading to a rubber 'bellow' that you're meant to squeeze & hold and release it at the right moment when the solder you want to suck away is liquefied. For various reasons I never had any success using it. Probably partly because the suction it creates is much too small and acts too slowly, especially compared to your standard desoldering tools which are spring-loaded. And in other part possibly because the act of suddenly releasing the bellow is not entirely compatible with keeping the desoldering tip steady and motionless at exactly the right spot. So it ended up in a box in the attic.

Now with the Chinese offering various nice and cheap parts I decided it was worth a shot to electrify it; a small vacuum pump, a solenoid valve, some buffer vessel and some tubing ought to be all that's required. The hacked soldering station I built has plenty of extra power available, both 12V and 24V (100W ring transformer). It just needs a rectifier for the vacuum pump and valve.

Having finally received the pump and valve this weekend I set out to acquire fitting tubing and make a quick 'n dirty prototype setup, as pictured.

Testing it, this vessel (a small soda bottle) builds up sufficient vacuum to have the tip suck air for over 5 seconds so that ought to be largely enough. But maybe the nozzle is simply too small. I think I have different sizes nozzles in that box in the attic, so I ought to try real-life desoldering to get proper test results.

Parts list (so far):

small 12V vacuum pump, aliexpress, $ 8.85
solenoid air valve, aliexpress, $ 4.97
Weller desoldering thing, $ unknown (*)
Various tubing, found in attic and elsewhere
bridge rectifier
momentary switch to mount on soldering iron
desolder section on/off switch 
12V relay (could be needed to drive the solenoid)
wiring
...
possibly an arduino and a pressure sensor to tell the pump when it should engage

(*) Not exactly advocating to purchase it, but Reichelt still sells it [[1]]