Introduction: Desoldering Pump and Hand Piece
Recently I found myself in need of a de-soldering pump to harvest parts from many circuit boards. While I do like the excitement of getting new equipment I find myself with limited space and piles of broken and derelict items.
I was able to cobble together a great working station from scrap and trash. Not one item was purchased for this build.
Yes it is overly complicated...
Step 1: Where to Begin
I started with an old refrigerator compressor including the associated associated copper tubing and such. Added some copper scrap from a previous build, electrical components scrapped from my day job and some wood from my bin.
To copy this build you will have to know how to hard solder and use basic hand tools.
Step 2: Test the Comperssor
I placed the compressor on some scrap cardboard, attached the start relay and plugged it in. This was done to first verify the operation and second find out which was the suction (vacuum) and discharge (pressure) side.
I just marked the cardboard with the appropriate information since I was likely to walk away from this build for several weeks before getting to finish it.
Next i decided to use the old refrigerator drier as a makeshift muffler and oil capture device. The discharge side tended to spit oil when I had it running. The bottom end was cut off and I fitted it to some scrap copper tubing then brazed it to the discharge port. I sand and flux all copper joints for a faster join.
The ends were then hand formed upward to keep the oil in. Yes I know that the moisture in the air will saturate the drier but with the amount of abuse the suction side is going to take, I feel that this is the least of my worries.
Step 3: For the Vacuum
I had to add some fittings to the suction tube of the compressor to accommodate for both the vacuum line to the tool and the vacuum tank.
I used a couple of recovered flare fittings with 1/4 inch tubing to make an extension and multi port vacuum inlet fitting.
The joints were all sanded and fluxed before being brazed together.
Step 4: Vacuum Cylinder
I used hard copper tube and sheet to create a vacuum reservoir cylinder. The tube was cut to an appropriate length and two end pieces were marked then cut from some copper sheet. Both ends of the tube were covered with the cut sheet then hard soldered into place.
The extra braze and copper was filed from the sides of the tube and a flat top brass end cap was brazed to one end again using sanding and flux.
The center of brass cap was 1/4 inch drilled open into the tank and an o-ring was inserted into the cap to help form a seal.
The whole tank was sanded and polished because it looks nice.
Step 5: Test the Assembly
Assemble the tank to the suction port then attach a test gauge to the port as well. I used an IKEA lamp cord with power switch to power the compressor.
It took less than 30 seconds to get to 28 inches of mercury and maintained it after the compressor was turned off.
I roughly formed the tubing into an aesthetic shape.
It is the next day for me and I have located the beat up vacuum gauge that I have used in previous projects. I will add it to the inlet along with an electrically activated solenoid valve.
Step 6: The Handpiece
This part is a work in progress The one shown here is functional but rather ugly. More of a quick proof of concept...
I found a scrap copper nozzle on an old refrigerator evaporator.
The copper nozzle fit into a brass waterline adapter in my melt bin.
I also had a small glass bottle from some essential oil, this mated to the waterline adapter with some filing of the threads.
I had to drill a small hole into the adapter then braze the copper nozzle into it. This hole is angled towards the bottle. the idea here is that any recovered solder will go into the bottle since flying chunks of metal can rarely make a steep angle turn.
I then formed a small section of copper tube then I brazed this to the outside of the adapter leaving enough clearance for the bottle.
Using the bottle as a guide I drilled and cut a 1/2 inch wide strip of copper to act as a bottle clamp. This was brazed to the pipe behind the bottle then all corners were sanded smooth. Being it is soft copper I can bend it quite easily to clamp the bottle in place.
I had to place a small o-ring around the hand piece adapter main body to create a good seal to the bottle.
Step 7: Electrics
I needed a way to switch the 120V solenoid valve so I pulled a 12V PCB relay and wall wart from my scrap pile.
The micro switch was wired for 12VDC and positioned within reach of my index finger. Strangely the whole assembly seems to fit in comfortably in my hand but I didn't even think of that when I was making it...
The switch is held in place with electrical tape.
I used a 28 inch section of 1/4 inch ID vinyl tube for the vacuum to hand piece. The wiring is held to the tube with a piece of wire loom.
The relay was conveniently diagrammed on the bottom. I wired it using the 12VDC to the coil and the 120VAC is between the N/O contacts on the hot lead. The connections were soldered then the whole assembly is heat shrunk with large tubing. With the wall wart powered the relay will now switch the solenoid on when the micro switch is pressed with my index finger.
Step 8: Base
I used a scrap piece of plywood cut to just larger than the overall footprint of the assembly.
The plywood was lightly sanded then stained with what I had in my garage.
The assembly was mounted to the plywood and the vacuum cylinder had a brass band placed around it for support.
Step 9: Experimental
I am working on a heated hand piece to make this a one tool operation. So far without success...