I was wondering if anyone has ever used a real vacuum pump, such as a general purpose electric 2.5 CFM vacuum pump to suck molten solder. I have been thinking for a while now of finding an air tank, keeping it evacuated it with the vacuum pump, and finding a heavy duty sucker with a quick trigger and fine nozzle. Building this isn't so difficult, but I am a little concerned with the design/nozzle and how the solder will clog it.--And also, a filter/solder capture device between the nozzle and vacuum hose (I believe a regular compressed air filter will do).
I have looked online for similar tools, and most of the desoldering tools I have found are the little inexpensive plastic suckers and the much more expensive desoldering stations with built in electric pumps and heating elements.
Yeah I know the inexpensive plastic suckers work. The thing is I'm looking to build a heavy-duty tool out of parts I already have available and are relatively common. If I could afford a professional desoldering station, I would definitely invest in one.
Perhaps I can explain. I have a few pallets worth of old electronics and I want to harvest the components and then organize & shelf them for later use. I have spent a couple of hours each day for the past month or so going through lots of it and desoldering every salvageable part with a soldering iron, heat gun, etc. (it's my pursuit of happiness). I want a sucker tool that doesn't need to be primed and cleaned for nearly every use.
It's kinda like changing a tire: using a tire iron to change 1 tire is fine, but if you work in an auto-shop it's impractical and that's why we use air powered impact wrenches. I'm interested in building the air powered impact wrench version of the solder sucker.
I think you could rig-up a vacuum pump to a standard solder-sucker. As long as there's a filter to keep the solder out of the tubing & pump, I think it wouuld work. But unlike a pro desoldering station, you'd have to use a regular soldering iron to melt the solder.
I don't remember if I've ever used one, but I've worked where they've had powered soldersuckers. We actually have one where I work now, but nobody uses it... Not in the 10-years, I've worked here... I don't know if anyone has ever used it... It's kind-of weird... it hooks-up to an air compressor and I assume it uses the [u]Venturi Effect[/u] to create suction (there's no vacuum pump).
This one uses a spring as a filter. It's metal, but I'm not sure what kind of metal. The spring-filter is about 1.5 inches long with a cone-shape at the end to keep the solder form simply passing-through. There's a plastic housing around the spring-filter.
The one I remember from before had a glass tube (maybe 3/8 or 1/2 inch diameter) with a cotton ball (or something like a cotton ball) as a filter.
Both had a hollow solder-tip, and the filter is right-after the tip, so the solder stays liquid 'till it hits the filter.
Both of these designs look like the filter would need to be cleaned frequently... Maybe there's a way to "trap" most of the solder (i.e. with gravity) rather than filtering it...???
I wonder if you had a fast enough pump, and the tip of the "sucker" was heated (to keep the solder molten), you could suck the solder through a water chamber (if the pump worked fast enough, a stream of bubbles would come from the intake, and little or no water would dribble down to the tip); the solder would stay molten until it hit the water and solidified. This (small) water chamber would need to be right near/at the tip of the device, though...
You use to be able to buy (maybe you still can?) desoldering irons (I remember them at radio shack), which looked like a soldering iron, but with a hollow "tip" at right angles to the heater core. This tip was hooked by a tube to a squeeze bulb (similar to the really el-cheapo desoldering bulb devices out there); you squeezed the bulb, heated the solder with your iron, and put the tip of the desoldering iron in the molten solder, then released the bulb to suck the solder up. The heating element for the desoldering iron was to keep the solder flowing (not to really start it on the PCB). There's an instructable out there on how to use such a desoldering-iron to make a hot-air soldering system, if you look around.
There's not really much out there to do what you want to do - in fact, you might find that a purchased (or possibly "home made") hot-air rework system might speed things up (think of it as a mini heat gun); there are a few tutorials/pages out there detailing how to build such a system (or you can buy one for around $120.00 USD or so via Ebay).
You mentioned using a heat gun - I had one guy tell me (here or on Electro Tech - I forget which) his method of "desoldering": Put your board over a cardboard box (do this outside, and wear goggles, long sleeves, pants, and maybe a dust mask or respirator), and heat the board all over with the heat gun (or use a propane torch). Heat the board until it just starts to singe, then whack it hard with a rubber mallet to knock the parts off into the cardboard box. Toss the board, don't try to go any further (anything else will just set the board on fire, and the parts won't be worth anything). Not sure though on how well such parts would work in the end, though...
Or you could always try the "Wild, Wild West's, Artemus Gordon" (or rather Dr. Miguelito Loveless) "vintage" approach.
Heat a solder pad and then knock your PC board against a newspaper or other disposable surface on your work bench. All the solder will be splattered on the paper and hopefully your pad will be clean. If not, repeat! Not very elegant, but it works for me all the time. ]
Of course, I sometimes use the plastic sucker and the solder wick.
