Soldering Basic Operation Manual
Basic Set
Basic Procedure
STEP 1: Preheat Soldering Iron
- Preheat for 2-3 minutes
- Temperature setting: 320-350°C (350-380°C for lead-free)
- Tip is ready when it shines silver
⚠️ Don’t work where air conditioning or fan airflow directly hits
STEP 2: Secure PCB and Components
- Place components and temporarily secure with masking tape
- Component leads should extend slightly through the PCB
STEP 3: Clean the Tip
- Sponge type: Wipe tip with slightly damp sponge
- Wire type: Insert into wire to remove residue
⚠️ Oxidized (black) tip will cause solder to be repelled
STEP 4: Apply Flux
- Apply small amount to pad and lead
- Work quickly after application (flux evaporates)
- Always close lid after use
STEP 5: Heat Pad and Lead (Most Important)
- Angle the tip (30-45 degrees)
- Heat both pad and lead simultaneously
- Heat for 3-4 seconds
Tip: Angling the tip increases contact area and transfers heat efficiently
STEP 6: Melt and Flow Solder
- Apply solder to pad and lead junction (not to the tip)
- When solder forms Mt. Fuji shape, remove solder first
- Wait 1-2 seconds, then quickly remove iron
⚠️ Removing slowly creates “horns”
STEP 7: Cool, Inspect, and Trim Leads
- Wait 5-10 seconds for solder to solidify
- Cut excess leads with nippers (1-2mm above solder joint)
Check Points:
- Is it Mt. Fuji shaped?
- Is surface smooth and shiny?
- Is solder attached to both pad and lead?
STEP 8: Continuity Check
- Check connections with multimeter continuity mode
- Buzzer sound means normal connection
- Focus on power lines and GND
10 Tips for Success
| # | Tip | Details |
|---|
| 1 | Preheat iron sufficiently | Wait at least 2-3 minutes |
| 2 | Keep tip clean | Clean frequently with cleaner |
| 3 | Angle the tip | Increase contact area for efficient heating |
| 4 | Heat pad and lead sufficiently | Maintain 3-4 second heating time |
| 5 | Use appropriate amount of solder | Just enough to cover the pad |
| 6 | Remove iron quickly | Slow removal creates horns |
| 7 | Don’t move until solidified | Wait 5-10 seconds |
| 8 | Work away from airflow | Avoid AC and fan airflow |
| 9 | Use flux liberally | Reapply if solder is repelled |
| 10 | Redo if failed | Remove with wick and retry |
Identifying Good Solder Joints
Good Examples
| Feature | Description |
|---|
| Mt. Fuji shape | Smooth, gradual slope |
| Smooth surface | Shiny, no bubbles or cracks |
| Good wetting on both | Covers entire pad and wets lead |
Bad Examples
| Failure | Appearance | Cause |
|---|
| Cold joint | Ball-shaped, not adhering to pad | Insufficient heating |
| Lifted lead | Only pad has solder, lead floating | Lead not heated enough |
| Bridge | Multiple pads connected | Too much solder |
| Horn/spike | Pointed tip | Iron removed too slowly |
Troubleshooting
Solder Removal Method
- Cut solder wick to appropriate length
- Place wick on solder to remove
- Press iron on top of wick
- When solder is absorbed, remove both wick and iron together
- Discard used portion of wick
Common Problems and Solutions
| Problem | Cause | Solution |
|---|
| Solder repelled | Oxidized tip, insufficient flux | Clean tip, apply flux |
| Solder won’t flow | Temperature too low, insufficient heating | Increase temp (to 350°C), extend heating time |
| Bridge formed | Too much solder | Remove excess with solder wick |
| Cold joint | Insufficient heating, moved before solidified | Extend heating time, wait for solidification |
| Tip turned black | Oxidation | Replace tip |
Safety Precautions
| Item | Precaution |
|---|
| Burn Prevention | Tip and solder are 300°C+. Never touch with bare hands. Don’t touch for 10+ minutes after use |
| Ventilation | Solder smoke (flux vapor) is produced. Use exhaust fan or open window |
| Fire Prevention | Always place on stand. Keep away from flammables. Turn off after use |
| Eye Protection | Solder can splash. Consider wearing safety glasses |
Lead-Free vs Leaded Solder
| Item | Lead-Free Solder | Leaded Solder |
|---|
| Melting Point | ~217-227°C (higher) | ~183°C (lower) |
| Working Temp | 350-380°C | 320-350°C |
| Difficulty | Slightly harder | Easier for beginners |
| Safety | Non-toxic | Lead is toxic. Handle with care |
| Use Case | Commercial products, general electronics | Hobby, personal use |
Recommended for Beginners: Lead-free solder (current standard, safer)
Tips for Lead-Free Solder
- Set temperature to 350-380°C
- Heat slightly longer (4-5 seconds)
- Use flux liberally
- Ensure adequate ventilation
