CS 3651 – Prototyping Intelligent Appliances Home Soldering Georgia Institute of Technology

2 Materials - Soldering Irons – Conventional Temperature Controlled More expensive but not unaffordable Power controlled Watt rating 15W about right for small electronics – even a bit hot in some cases Some are switchable Battery Powered Allegedly about 15W effectively Portable, no cord, light Heat conductive tip lowers risk of burns

3 Materials – Soldering Irons (cont.) Cold Heat Activated when low resistance on the tip Very heat conductive material on the tip – runs small current until connection, then higher current Electrical resistance of solder and tip causes heat Different technique Battery powered Only hot when soldering or immediately after Not good for desoldering Fragile

4 Materials – Solder – Kinds of Solder Cores Flux Improves flow Prevents Corrosion Can form salt – “no clean” Types Acid Metalworking Can have poisonous vapors Rosin Common Electronics Water-Soluble Environmentally responsible Can be corrosive Removal More active, more salt Easier to remove Flux-free Rare – mostly research, manufacturing

5 Kinds of Solder (cont.) Lead Slower solidifying Lowers melting temperature Reliability Poisonous RoHS Size Chemical ratio Unspecified and 60/40 or 63/37 -> likely tin / lead Otherwise, typically not specified or materials named because many other combinations exist

6 Materials – Accessories Grips Soldering involves attaching two metal parts together – so there will always be 4 parts involved: Object A Object B Solder Soldering iron Solution: stabilize at least 2 of them (or 3?) Pliers Chip Clips Vice Grip “Helping Hands”

7 Accessories (cont.) Surface Sponge Mousepad Heat Sink / Clip Stands Extension cord (!) Note: low wattage Tips Size/Shape Wattage Connection

8 Concepts Tinning the iron When first using the iron or when coating is wearing off Protects the tip from corrosion Better heat flow Too Much Heat Melt the solder May need to prepare surfaces Result not as solid, but often good enough Accessories Tips Lower Power Electrostatic discharge Everyone seen anti-static bags? Static + electronics = bad Try to avoid generating it (no wool socks, etc) Anti-static wrist straps Don’t touch the iron! Many irons are already grounded

9 You can do it! The end