Soldering Tips

Soldering Tips

Soldering is accomplished by quickly heating the metal parts to be joined, and then applying a flux and a solder to the mating surfaces. The finished solder joint metallurgically bonds the parts - forming an excellent electrical connection between wires and a strong mechanical joint between the metal parts.

1.  Turn on the soldering iron. This may seem obvious, but you do have to pay attention to the temperature level. For the Weller irons we have at the lab benches, somewhere between 60 and 70 should be good enough. The hotter you make the soldering iron, the more you’ll risk burning up your components.   

2.  Wet your soldering sponge - this is good for cleaning the tip of your soldering iron and wiping any excess soldering juice from your board (you’ll see what this means). There’s a big bottle of water in the lab for wetting sponges. 

3.  Get your soldering board. In general it’s better to get the ones with plated holes, and even better to get the ones with connected traces (for power and ground). 

4.  Plan your layout - You have a limited amount of space, so use it wisely. Remember the rules of compartmentalization, and solder your circuit in blocks, so that you can test each one. In general, you’ll want to solder with your chips and components on the side of the board without plating.

5.  Tinning - First, you want to wipe the tip of your soldering iron on the wet sponge to clean off any gunk. Then, “tin” the tip by melting just a little bit of solder on the end of the soldering iron. This helps create better thermal conduction.  

6.  Get physical first - If you’re soldering two elements together (say two wires), make sure they have a good mechanical connection (i.e. twist them together) before you solder them. This will ensure that you maintain a good overall connection. For soldering to a board this is less crucial. 

7.  Heat the joint - The basic idea for soldering is to heat the two elements you want to join enough so that the solder melts onto them. You shouldn’t need to even touch the soldering iron with the solder. You only need enough solder to cover the joint.  

8.  The three-second rule - In general, ICs are designed to handle soldering heat, but not for a long amount of time. The three-second rule is usually a good one to follow (don’t hold the soldering iron to your component for more than three seconds). For multiple pin ICs, you may want to solder two or three pins at a time, stop and blow on the chip, then solder a few more pins, etc.  

9.  A good job - When you’re soldering onto a board, you should shoot  for your solder joint to look more like a concave circus tent than a balloon - this reduces the chances that your solder joints will cause nasty short circuits. 

10.  No soldering with your mouth! - There is no other activity that calls for the convenience of a third hand more than soldering. You may be tempted to do “clever” things like hold the soldering iron between your teeth so your hands can be free to hold two components together. DON’T DO THIS! We don’t like the emergency room any more than you do .