How to care for your soldering iron. Basic soldering information How to solder wires together. How to solder components to circuit board. What makes a good solder connection. 1
Soldering iron care The metal tip should always be coated in solder. If no solder is on the tip, it to corrode (oxidation). Hot metal oxidizes quickly. Solder acts as a shield between the metal of the tip and the oxygen in the air. Adding solder to the tip is called tinning. 2
Finishing care When you are done with your soldering work, turn the soldering iron off. When it is still hot, melt a large drop of solder over the end of the hot tip. A dirty looking soldering iron (covered in solder) is better than a clean iron. The soldering iron will be protected from corrosion when not in use. 3
Corroded tips Do not file or sand the tip of the soldering iron down to remove corrosion. This can ruin the tip. Try and acidic compound flux, which I will talk about later or Coca- Cola. Or buy a new tip, they run about $5. 4
Basic information ALWAYS WEAR EYE PROTECTION! The tip of the soldering iron gets hot. The handle stays cool. The soldering iron comes with a holder. Other soldering irons may come with a small stand for the tip. The sponge is to clean the tip as necessary. Get the sponge wet, but use distilled water if possible. Bottled water works as well. Always tin the tip after cleaning. 5
Soldering Irons PLUG THE SOLDERING IRON IN AND TURN IT ON. Turn the dial to 3 ½ for now. New soldering irons come with a layer of solder on them, but we want to pay attention to the tip. As it heats up, add more solder to it. Always have solder on the tip. Some irons have a dial. Some just plug in and heat up. 6
Solder Solder is a mix of two or more metals that has a lower melting point than the individual metals. All solder used to be a mix of lead and tin. Since lead is a toxin, lead-free solder is now readily available but it is harder to work with. 7
Solder Lead solder melts at 163 degrees Celsius. Common lead-free solder melts at 217 233 degrees Celsius. 60% Sn 40% Pb 163 C Toxic 63% Sn 37% PB 163 C Toxic 96% Sn 3% Cu 1% AG 217-233 C Non-Toxic* Kester 44 Rosin Core Solder 60/40 0.031" (* Has much more flux which is an acid, this causes other problems. We will be using leaded solder because it is easier to work with.) Check to see if you need to tin the tip of your iron. 8
Soldering Soldering is a very important skill. To get better at soldering PRACTICE! Soldering makes both a physical and electrical connection. Take out a short length of wire (approximately 20 cm). Use wire strippers to strip 1.5 cm from each end. Bring the ends together and twist the bare copper wire together. You want a good physical connection before you add the solder. 9
Wires are twisted tightly together. 10
Soldering Solder flows towards the heat. If the wire is cold and the tip of the soldering iron is hot, solder will not go to the cold wires. Touch the copper wire connection with the hot tip of your iron. Keep the hot tip on the copper wire for 5-6 seconds. Add solder to the point where the tip of the iron touches the copper wire. 11
12
Soldering Do not paint with the soldering iron. Hold the soldering iron steady on the copper wire. Push as much solder as needed into the connection. A good solder connection has the liquid solder wick into the wires. Ideally you should see the structure of the copper wires beneath a shiny, silver solder coating. You do not want a drop on the side of the wire connection. Remove the solder. Wait 1-2 seconds. Remove the soldering iron. 13
You can still see the structure of the wires underneath the layer of solder. *Note the sharp wire ends still sticking out (might cause issues). 14
Let s practice soldering Take out the worksheet and follow the soldering instructions. If you have questions, ASK. If you are confident in your soldering abilities, look to help another. 15
Waterproofing a solder joint When working with an ROV, solder joints will be going underwater. Electrons/electricity escaping into water is bad. The chance of electrocution is small. The chance of wires corroding and quickly becoming unusable is very high. In a MATE competition, having wires leaking electrons to the water is not allowed. It may shut down the power supply being used to power your vehicle. 16
Waterproofing a solder joint Tools needed: Heat gun / Heat shrink tubing Hot glue gun / Hot glue Heat shrink is a plastic tube that shrinks in diameter when heated up. It will provide a waterproof plastic coating over a solder joint. Hot glue surrounding the solder joint will provide a waterproof coating as well. Used together, hot glue inside shrink wrap will doubly protect the solder joint. 17
Waterproofing a solder joint Take/Cut another 20 cm length of wire. Use wire strippers to strip 1.5 cm from both ends of the wire. Cut a 4 cm length of red shrink wrap. Slide the shrink wrap over the wire. Keep it as far away from the solder joint as possible. 18
Waterproofing a solder joint Plug in the hot glue gun and insert a glue stick (if needed). Solder the ends of the wire together. Apply a thin layer of hot glue over the solder joint. If needed, add a second layer hot glue on the other side of the solder joint. Once the glue cools, slide the 4 cm length of shrink wrap over the solder joint and solid glue. 19
Waterproofing a solder joint Use a heat gun to apply heat to the heat shrink tubing. Slowly move the heat gun back and forth over the tubing. The tubing will shrink. After a time, the hot glue will remelt inside the tubing and be pushed all around and over the solder joint inside. Hot glue coming out the ends of the tubing is a good sign. 20
Let s practice waterprooofing Take out the worksheet and follow the waterproofing instructions. If you have questions, ASK. 21
22
Printed Circuit Boards (PCBs) are wires already set into place. Does this wiring look familiar? 23
The SeaMATE PufferFish kit has a board with this wiring laid out in it. Install a switch (a component) onto the board and most (but not always all) of the wiring is complete. 24
Components are soldered onto the board Components have leads (wires) that push through metal* holes in the board. Use a fine tip soldering iron to secure the component in place physically and electrically. Clip the excess leads off after* you solder the component. 25
Other hints about though-hole soldering The usual soldering rules apply You want to see a smooth, shiny surface You want the solder to look like a Hershey s Kiss Do not let the solder or leads from one hole touch a nearby hole. Get a good soldering iron. Take proper care of the iron. A good soldering iron makes soldering easy. A bad soldering iron makes soldering hard. Heat the metal around the hole for 5 to 8 seconds before adding solder. Solder wants to flow towards the heat. 26
We will attach a DPDT (double pole, double throw switch), LEDs and resistors to the old PufferFish boards for practice. We will then add a motor and power wires to watch it work. 27