Home made SMT Desoldering Station
Working with SMTs (surface mount technology components) is quite difficult without an smt hot air pencil.
The prices of smt stations are too high, so I decided to build it by my own, the result is very impressive. Anyone with basics electronics can try to build it, it's made with common materials. 
An smt desoldering station is made up of :- an heater, that is a powerful solder (min 50watt)- an hot exchanger ( IRON WOOL)- an air pump Surfing the web I find some desoldering homemade stations but all using an aquarium pump.
Cause I can't get that pump I decided to substitute it with a mini hair dryer, those used travel, this last have inside a 12 v motor cause the internal resistance coil used to hot the air is also used to reduce the 220 AC to 12 volt, infact inside this little dryer you'll find the coil, the motor and a rectifier bridge. The only thing you need is the motor and the tube chassis so you have to cut the handle. 
First of all you have to get the hotting element, I used an old 60 watt iron , placing the hotting element inside the end of a long iron tube, (about 20 cm, you can also use the same solder tube if there are no holes ) then surrounded the element with Iron Wool (do not press it inside too much or there will be no air flow) that used for washing pots, this trick make the air go slowly and hotter before get out. Then I used a 1 meter plastic tube ( 0.5 cm ) to transfer the air to the pen. For the tip you can use some hardware shop material, it must be iron, shorter and pointed (never use aluminium or brass they will reduce the out temperature, preferably use copper ). Once you have made the pen you can test it with your breath. Ensure there is no other hole JUST the one from witch you blow your air in, you can also use some hot glue but only for the tail of the solder obviously not for the point !To test: switch on the solder, wait some minutes, lightly blow into the plastic tube, PUT the point at 2 cm from a paper, in 3 seconds the paper must begin to burn or became dark. IF it 's so you are ready to build the air pump, if it's not so, keep on reading here.Perhaps your solder is less than 40 watt powerful or you have stocked to much iron wool, so for your blow it's really hard to pass through , but also there may be too little iron wool and the hot isn't transferred quitely .
Experiment with the quantity of iron wool and place the hotting element as near as possible to the tip . Building the air pump isn't so much difficult as it seems, first of all get your mini hair dryer, remove everything except the motor and the final rotor, cut only the handle and the rotor's plastic cover, that from which the air enter ( to get more air flow ), take a plastic 66cl pet bottle (coke, fanta and so on ) cut it making such as a funnel, insert it in the out hole of the dryer use some hot glue to fix it, better if it 's inserted with a little pressure, then take the cap , get a short brass tube of 0.5 cm diameter, make the hole on the cap to fit perfectly the tube, insert the tube, use some hot glue to fix it .Now you can use such metal tube to fit the plastic tube to get air outside . Use a variable power supply 6-12 volt to power the motor dryer and control the air flow, you can use the supply project inside this page next. LOOK at my picture and you will understand anything I mean, by regulating the power supply you regulate the temperature, the more air you pump the more rapidly will be the desoldering. Obviously there is no guaranty that a desoldered component will still function using this kind of station ! Hotting for too much time ( more than 10 secs.) will surely destroy the SMT component. At the end you will have a desoldering smt station for less than 50 $ , with characteristics not really different from those commercials ones.Remember to write to me if you need some extra informations or simply build something !!!!GOOD WORKING !!
posted by alfred @ 19:07
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