Desoldering Tool
It is a tool for desoldering (multi leg) electronic components with 3 or more pins.
Theory behind this project is fairly simple. Dissolved solder in heated container heats all contacts of electronic component placed together with PCB on this tool. All you have to do is remove component from PCB with pliers or with tweezers. So with this device you can easily desolder 25 pin LPT conector from 2 sided PCB.
Original article on my site here
Theory behind this project is fairly simple. Dissolved solder in heated container heats all contacts of electronic component placed together with PCB on this tool. All you have to do is remove component from PCB with pliers or with tweezers. So with this device you can easily desolder 25 pin LPT conector from 2 sided PCB.
Original article on my site here
Can Selection
First find some tin can, like this one from the picture.
Can Preparation
Then cut the bottom of the can. Later it will be used as container for melted solder. 1-2cm is sufficient height for container.
Construction of Heater
For heater you need heater wire (NiCr). Usualy caled "cekas" od "nichrome". If you don't have any, take some from old heater in blow dryer or heating unit, and wind off 1m of wire. Measure resistance because you will need this information later in construction.
Before calculation you must have 2 more parameters . Power and voltage of heater.
Power of my heater is 100W, recommendation is not to go below that because it takes too long to melt down solder after power up.
Voltage must be adapted to power source that you will use. I have laboratory power source with regulation from 0-35V and I have chosen 30V for voltage of my heater.
Calculation:
U=30 V
P=100 W
rt=28,6 Ohm/m (resistance per one meter)
Rt= ? (resistance of heater)
Rt = U2 / P = 302 / 100 = 900 / 100 = 9 Ohma
Length of heater wire
L = Rt / rt = 9 / 28,6 = 0,3m
If you don't want to calculate parameters and you have a power supply with voltage regulation, just take piece of wire, connect it to power supply and rise voltage until wire (heater) gets to red glow. This method can be used for checking the calculated parameters.
On the picture is my heater. Coiled on 3mm drill borer and extended to desired length.
Before calculation you must have 2 more parameters . Power and voltage of heater.
Power of my heater is 100W, recommendation is not to go below that because it takes too long to melt down solder after power up.
Voltage must be adapted to power source that you will use. I have laboratory power source with regulation from 0-35V and I have chosen 30V for voltage of my heater.
Calculation:
U=30 V
P=100 W
rt=28,6 Ohm/m (resistance per one meter)
Rt= ? (resistance of heater)
Rt = U2 / P = 302 / 100 = 900 / 100 = 9 Ohma
Length of heater wire
L = Rt / rt = 9 / 28,6 = 0,3m
If you don't want to calculate parameters and you have a power supply with voltage regulation, just take piece of wire, connect it to power supply and rise voltage until wire (heater) gets to red glow. This method can be used for checking the calculated parameters.
On the picture is my heater. Coiled on 3mm drill borer and extended to desired length.
Heater Isolation
Finished heater must be somehow isolated from metal housing. I have used ceramic insulators removed from old baking oven heater. If you don't have insulators buy them in repair shop for kitchen appliances.
Can Attachment
Can from beginning of text somehow must be attached to housing, for that purpose main is drilled through middle and PCB spacer is attached to can with screw. Plain screw with few nuts can be used.
Heater Installation
Heater installed in can slot.
Heater Mounting
Heater is pressed to can with grill from PC fan.
Legs Mounting
Screws with nuts are used for "legs" of device, and ceramic connection block is mounted to hold outlets of heater.
First Run
Desoldering tool connected to power supply, and peaces of solder are melting in can.
Tool in Use
On next pictures desoldering proces is shown step by step.