TIPS FOR SOLDERING AND DE-SOLDERING.
First of all needless to say the apparatus you are working on must be switched off & un-plugged from the wall, it can be a good idea to wear safety glasses when soldering as soldering flux is annoying in your eyes, if a piece of wire has spring in it, it may flick solder at you, a well ventilated area is good, a small fan on the workbench can be used to draw fumes away, don't hold things to close to your face when soldering them, keep them at arms length away. A bench vice with a magnifying glass attached is best used for soldering really fine work that is hard to see, get in the habit of putting the soldering iron down in it's holder when not soldering do not leave the soldering iron in your hand if picking up a board or component to examine or adjust it. Don't try doing a juggling acts with soldering irons and components. Keep the temperature turned down low unless soldering heavy terminals. When testing switch the iron off if you don't think it will be needed for a while. Switch off the soldering iron if leaving the room for any reason, switch every thing off for that matter in case you are distracted and don't return. Well that ought do for safety for now.
With a new iron or bit make certain to tin it, it's quite simple switch on the iron and allow the tip to heat up, soon as it's hot enough start melting resin core solder over the bit letting the melted solder drip off while turning the iron over to coat all sides, where the resin core is pushed on to the tip is where the flux best cleans and coats. Wipe the solder of the tip on a moist sponge then repeat. At this point where the tip is tinned is where the solder will take to the bit from now on, as the rest of the bit will eventually tarnish, so if you want a bit that holds a lot of solder and has a large heating contact area, tin it say half way up or if you want a tip that holds only a little solder with a small contact area, just tin the tip of the tip.
Old bits can get burnt stopping the solder from taking to them, rub a bit of chalk in to an old file clean up the bit then re-tin it, I say with an old file because solder gets stuck in files. If the bit is one with a non-tarnish coating get as much solder off as possible with a damp sponge then give it a rub with some steel wool and re-tin it, Do Not file it.
When soldering keep your bit clean by regularly wiping on a damp sponge then feed some solder on to the bit and wipe it off again, do this right before starting and when you see burnt black flux starting to build up, it's good to keep a bit of solder on the tip all the time to stop it from burning.
To solder a joint first feed a little bit of solder on to the tip to create a heat conducting area then place the tip on the joint trying to contact both parts of the joint then feed the solder on to the joint where the two parts meet not on to the tip of the iron, in some cases it is necessary to feed the solder to where the tip of the iron meets the joint.
When soldering three wires on to a terminal hold the wires on to the terminal with the iron, feed solder on to the joint, put down the solder, pick up a screwdriver and hold the wires with the screwdriver, then remove the iron and allow the joint to cool. Don't let a joint move while cooling down this can leave cracks causing dry solder joints.
To solder a heavy joint like a wire to the back of a pot, tin the wire to be soldered by heating it and feeding solder on to it. Turn up the heat on the iron, tin the back of the pot in this way, feed solder on to the tip of the iron, place the tip on the back of the pot. Feed solder on to the pot wile rubbing the tip around the area where you want the solder to go, rubbing helps the flux to clean and the solder to take. Remove any excess solder, hold the wire to the pot with the tip of the iron, feed a bit of solder on if necessary, put down the solder, pickup the screwdriver and hold the wire with it, then remove the iron, let the joint cool down by it self. Occasionally when applying solder to new pots and terminals it is necessary to give them a bit of a scrape with a screwdriver before starting, to remove some of the hard lacquer, otherwise the solder will not take, is not necessary to remove all lacquer, just enough to break through to the surface, the soldering iron will do the rest, the same applies when corrosion is present as well, except it will be necessary to scrape away more of the corrosion.
Note that wires and terminals should be tinned before they are put together and soldered. The leads of components such as capacitors, resistors, transistors, IC's do not need tinning since they are already tinned.
Power diodes & protection resistors like those connected to the emitters of power transistors or those in supply lines need to be standing 5mm to 7mm of the board to prevent scorching or burning of the board from heat and in the event of them burning out, as well as to allow air to circulate underneath. Components like resistors connected to test points should be standing sufficiently high to allow a probe to be hooked on.
Integrated circuits or small transistors must be soldered as quickly as possible using a low temperature, as excessive heat will damage them. Paper clips can be clamped over the pins of IC,s to drain heat away wile soldering or to prevent static damage to cmos chips while handling. If you want you can solder two pins of one IC, go to another IC solder two pins, come back do another pin and so on. If there is just one IC with lots of pins solder a few pins allow the IC to cool before doing a few more pins. Just be quick with the time that the tip is on the pin, IC's can take so much heat for so long. You need to be real quick with guitar pick-ups as well, and you have to be reasonably fast as capacitors.
Don't push IC's right down on to the board, push them down so that their pins only stick out the other side approximately .5mm, in this way if you want to remove them you can get something under neath them to pull them up as well as get the point of a solder sucker right down on to the board.
Bluetac can come in real handy to hold components in place when putting together boards. It's not really a good idea to hold resistors and capacitors down by bending their leads over because this makes them real difficult to remove, it's alright to stop components from falling out when placing them on to a board, but straighten the leads out again before soldering, Use a bit of bluetac to hold components down on to the board! Using a ruber thimble on one of your fingers is a good way if you want to hold components down on to the board with one of your fingers while soldering, if you don't have a thimble fold up a small piece of cardboard and tape it to your finger, this should stop you from burning your finger, components like resistors can get pretty hot when being soldered.
Removing Integrated Circuits from boards with or with out the right tools can really reck a board, especially the plated through ones sints the solder is all the way through. Therefore if the IC is a relatively inexpensive one and you are pretty well 100 percent certain it has failed. Get the smallest pair of cutters you can lay your hands on and cut the pins on the chip one at a time close to the chip from the top of the board. Remove the IC this way then you can solder a new IC straight on to the pins sticking up from the board, if you were really careful not too have damaged the old chip you can solder it back to if you want. Or remove the pins one at a time and replace them with a socket, you can use the pins as a socket too for testing a new IC before soldering to the pins or removing the pins.
Solder wick or any of the many de-soldering tools can be really useful, if you have a solder sucker with a metal body try lubricating it with some auto fluid, brake fluid, vegetable oil, rubber grease or margarine, you will be amazed with the improvement!