Soldering & The Tinning Process

Electronics 1CVHS

What is Soldering?

Solid electrical connection

Mechanically connects metal to metal

Electronic solderingsoft soldering

350° F

Wave Soldering Machine

Wave- Intake

Successful Soldering

1. Correct solder and flux

2. Required equipment

3. Clean soldering pencil tip

4. Safety

Solder

Metal alloy of tin and lead

Symbol for tin - Sn

Symbol for lead - Pb

63% tin and 37% lead

Solder – 63Sn/37Pb

No mushy range

Eutectic alloy

Lowest melting solder alloy

350°F - 600°F

Solder - 60/40

Use 60/40 in electronics because less expensive

Standard Wire Gauge - SWG

SWG .031

Flux

Helps solder flow

Removes oxidation

Protects copper while solder melts

Flux

Rosin-based is used for electronics

Acid-based is corrosiveDO NOT USE IN ELECTRONICS

Used in stain glass lampshades

Flux

Available as a paste

Available as a liquid

Solder has a rosin flux core

Equipment

Soldering gun Instant heat - high watts

Too hot

Copper tracks and pads come off board

Damage components

Equipment

Soldering iron (pencil)

Slower warm-up

Lower wattage - 25 watts

Tight spots

Various tips - conical best

Clean Tip

Tip becomes oxidized with heat

Wipe off oxidation with damp sponge

Clean Tip

File away heavy oxidation

Clean Tip

Tin pencil tip

Prevents oxidation

What is tinning?

“Tinning” means covering the tracks & pads on your PCB with solderPCB tracks & pads are made of copperWhen exposed to air & oils on your skin, copper oxidizesPCB must be tinned in order to prevent corrosion & ensure a good electrical connection

Steps for tinning your PCB

1.Clean all tracks

2.Apply flux to all tracks

3.Heat tracks & add solder

4.Spread & add solder over all tracks

SafetySolder over workbench

Treat pencil as always hot

Safety glasses must be worn

Solder Contains Lead – Washing hands is recommended

Safety

Put pencil in stand

Review

1. The best ratio of solder to use in electronics is:

2. This is because:3. We use _______-based flux4. What is the difference between a soldering

gun & pencil?5. Why do we tin our PCB’s6. What safety considerations are important to

remember when soldering?

Demonstration