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Keyboard Soldering Guide: Build Your First Custom Keyboard

8 min read

Keyboard Soldering Guide

Soldering opens the door to custom keyboard builds, repairs, and modifications. This guide teaches you everything you need to know to confidently solder your first keyboard.

Why Learn Soldering?

Custom Keyboards

Many premium keyboards require soldering:

  • Custom group-buy keyboards
  • DIY keyboard kits
  • Ultimate switch selection (not limited to hot-swap compatible)

Repairs

Fix broken keyboards:

  • Replace damaged switches
  • Fix lifted pads
  • Repair USB connections

Modifications

  • Convert hot-swap to soldered for stability
  • Add components (LEDs, resistors)
  • Create custom layouts

Soldering vs. Hot-Swap

Hot-Swap Keyboards

Pros:

  • No soldering required
  • Swap switches anytime
  • Beginner-friendly
  • Experiment with switches easily

Cons:

  • Limited to hot-swap compatible switches
  • Sockets can wear out
  • Less stable connection
  • Slightly more expensive

Soldered Keyboards

Pros:

  • Most stable connection
  • Works with all MX-compatible switches
  • No socket failure
  • Premium feel

Cons:

  • Requires soldering skills
  • Switch changes require desoldering
  • Mistakes harder to fix
  • One-time commitment

Verdict:

  • Beginners: Start with hot-swap
  • Enthusiasts: Learn soldering for ultimate flexibility
  • Both are valid options

Soldering Tools and Materials

Essential Tools ($50-100)

Soldering Iron (Most Important):

  • Temperature controlled: 300-400°C (570-750°F)
  • Wattage: 40-60W minimum
  • Recommended: Hakko FX-888D, TS100, Pinecil
  • Budget: Any adjustable temperature iron ($30-50)

Solder:

  • Type: 63/37 or 60/40 tin-lead solder
  • Thickness: 0.6-1.0mm diameter
  • Flux core: Yes (rosin core)
  • Lead-free alternative: Available but harder to work with

Solder Sucker (Desoldering Pump):

  • Spring-loaded pump
  • For removing solder
  • Budget option: $5-15

Flux:

  • Rosin flux paste or liquid
  • Improves solder flow
  • Makes soldering easier
  • $5-10

Tweezers:

  • For holding components
  • Placing switches
  • $5-10

Optional Tools ($50-200)

Desoldering Gun:

  • Electric solder sucker
  • Much faster than manual pump
  • Recommended: Engineer SS-02 ($50)

Soldering Station:

  • Temperature control
  • Better heat consistency
  • Recommended: Hakko FX-888D ($100)

Brass Sponge or Tip Cleaner:

  • Cleans soldering iron tip
  • Better than wet sponge
  • $5-10

Helping Hands:

  • Holds PCB steady
  • Third-hand clips
  • $10-20

Multimeter:

  • Test connections
  • Troubleshoot issues
  • $15-30

Safety Equipment

Ventilation:

  • Soldering produces fumes
  • Work near window or use fume extractor
  • Don’t breathe fumes directly

Eye Protection:

  • Safety glasses
  • Prevents solder splatter injury

Heat-Resistant Mat:

  • Protects work surface
  • Silicone mat ($10-20)

Soldering Basics

How Soldering Works

Process:

  1. Heat both the pad and the pin with soldering iron
  2. Apply solder to the heated joint (not the iron!)
  3. Solder melts and flows into the joint
  4. Remove solder, then remove iron
  5. Let joint cool without movement

Key Principle: Heat the joint, not the solder. Solder flows to heat.

Good vs. Bad Solder Joints

Good Joint:

  • Shiny, smooth surface
  • Concave cone shape around pin
  • Solder flows evenly on pad and pin
  • No gaps or excess solder

Bad Joint (Cold Joint):

  • Dull, grainy appearance
  • Blob-like, not smooth
  • Poor electrical connection
  • Happens when joint wasn’t hot enough

Bad Joint (Too Much Solder):

  • Large blob covering multiple pads
  • Risk of shorts (bridging pads)

Bad Joint (Too Little Solder):

  • Pin not fully covered
  • Weak mechanical connection
  • Can break easily

Step-by-Step: Soldering a Keyboard

Step 1: Gather Materials

You’ll Need:

  • PCB
  • Switches (matching your desired count)
  • Plate (optional, depends on build)
  • Stabilizers (pre-installed on PCB)
  • Soldering iron
  • Solder
  • Flux (optional but recommended)

Step 2: Prepare Workspace

  1. Set up heat-resistant mat
  2. Organize tools within reach
  3. Ensure good lighting
  4. Open window or turn on fume extractor
  5. Heat soldering iron to 320-350°C (600-660°F)

Before soldering, test PCB:

  1. Plug PCB into computer
  2. Use tweezers to short switch pad pairs
  3. Use keyboard testing website (keyboardtester.com)
  4. Verify all keys register

Why? Don’t want to solder 100 switches only to find a dead PCB.

Step 4: Install Stabilizers

  1. Insert stabilizer housings into PCB
  2. Screw in (screw-in type) or clip in (snap-in type)
  3. Insert wire into housings
  4. Test stabilizer movement (should be smooth)

Note: Stabilizers MUST be installed before switches (can’t access after soldering).

Step 5: Insert Switches

With Plate:

  1. Place switches into plate
  2. Align switch pins with PCB holes
  3. Press switches through plate into PCB
  4. Ensure all pins go through PCB (not bent!)

Without Plate (Plateless Build):

  1. Insert switches directly into PCB
  2. Ensure switches are flush with PCB
  3. May need tape to hold switches while soldering

Important:

  • Check switch orientation (LED cutout faces same direction)
  • Ensure pins aren’t bent
  • Switches should sit flush

Step 6: Solder First Switch

Practice on corner switch first:

  1. Heat the joint: Touch iron tip to both the pad and switch pin (2-3 seconds)
  2. Apply solder: Feed solder wire to the joint (not the iron tip!)
  3. Solder flows: Solder melts and flows around pin and pad
  4. Remove solder wire: Pull solder away from joint
  5. Remove iron: Lift iron from joint
  6. Let cool: Don’t touch or move switch (2-3 seconds)

Check:

  • Solder forms smooth cone around pin
  • Pin is fully covered
  • No solder bridges to adjacent pads

Step 7: Solder Remaining Switches

Strategy:

  • Solder a few switches to hold PCB and plate together
  • Then solder remaining switches systematically
  • Work in rows or columns (organized approach)

Tips:

  • Don’t rush (quality > speed)
  • Clean iron tip regularly (on brass sponge)
  • Add flux if solder isn’t flowing well
  • Take breaks (prevents fatigue mistakes)

Step 8: Inspect Joints

After soldering all switches:

  1. Visually inspect every joint
  2. Look for cold joints, bridges, or insufficient solder
  3. Reflow any questionable joints (reheat and add solder if needed)

Reflow Technique:

  1. Heat joint with iron
  2. Add a tiny bit more solder if needed
  3. Let solder flow and cool

Step 9: Test Keyboard

  1. Plug keyboard into computer
  2. Test every key (use keyboard tester website)
  3. If key doesn’t work:
    • Check solder joint on that switch
    • Reflow joint if cold or insufficient
    • Check for bridged pads (shorts)

Step 10: Clean PCB (Optional)

Remove flux residue:

  1. Use isopropyl alcohol (90%+ concentration)
  2. Scrub with soft brush or cloth
  3. Let dry completely

Why? Flux residue is sticky and attracts dust. Cleaning makes PCB look professional.

Desoldering Switches

When to Desolder

  • Switch is faulty (chattering, not registering)
  • Want to change switches
  • Made soldering mistake
  • Bought used keyboard and want to modify

Desoldering with Solder Sucker

Step 1: Heat Joint

  1. Heat soldering iron to 350-380°C (slightly hotter)
  2. Touch iron to solder joint until solder melts

Step 2: Remove Solder

  1. Place solder sucker nozzle near joint
  2. While joint is molten, trigger solder sucker
  3. Solder gets sucked into pump

Step 3: Repeat

  1. Clear pump (empty solder)
  2. Repeat until most solder is removed

Step 4: Remove Switch

  1. Gently wiggle switch while heating pins
  2. Switch should pull out once solder is cleared

Tips:

  • Work on one pin at a time (2 pins per switch)
  • Don’t force switch out (can damage PCB pads)
  • Add fresh solder if old solder won’t flow (helps heat transfer)

Desoldering with Desoldering Gun

Easier and Faster:

  1. Heat gun tip while placing on joint
  2. Trigger vacuum while heating
  3. Solder is heated and sucked up simultaneously

Recommended Tool: Engineer SS-02 ($50) - best budget desoldering gun.

Desoldering Wick (Alternative Method)

How It Works: Copper braid absorbs molten solder.

Technique:

  1. Place wick on solder joint
  2. Press hot iron onto wick
  3. Solder melts and wicks into braid
  4. Move to clean section of wick, repeat

Pros:

  • Cheap ($5 for roll)
  • Portable

Cons:

  • Slower than solder sucker
  • Uses up wick quickly

Common Soldering Mistakes

Bent Pins

Problem: Switch pins bent during insertion, don’t go through PCB.

Solution:

  • Carefully straighten pins with tweezers before inserting
  • Don’t force switches into PCB

Cold Solder Joint

Problem: Joint didn’t get hot enough, solder looks dull and grainy.

Solution:

  • Reflow joint with more heat
  • Ensure iron is at correct temperature (320-350°C)

Solder Bridges (Shorts)

Problem: Solder connects two adjacent pads, causing keys to register together.

Solution:

  • Use solder wick to remove excess solder
  • Add flux and reflow to separate pads

Lifted Pads

Problem: PCB pad detaches from board (from overheating or excessive force).

Solution:

  • Advanced repair: jumper wire from lifted pad to trace
  • Prevention: Don’t overheat pads, gentle when desoldering

Too Much Solder

Problem: Excessive solder creates blobs, risk of bridges.

Solution:

  • Use solder wick to remove excess
  • Less is more—small amount of solder is enough

Switch Won’t Register

Problem: Key doesn’t work after soldering.

Solution:

  • Check solder joint (reflow if cold)
  • Test with multimeter (continuity between pin and trace)
  • Check for damaged switch

Soldering Tips and Best Practices

Tip 1: Tin Your Iron

What: Coat iron tip with thin layer of solder before starting.

Why: Improves heat transfer, protects tip from oxidation.

Tip 2: Use Flux

What: Apply flux paste to pads before soldering.

Why: Solder flows better, easier to get good joints.

Tip 3: Clean Tip Regularly

What: Wipe iron tip on brass sponge or wet sponge frequently.

Why: Removes oxidation, maintains heat transfer efficiency.

Tip 4: Don’t Overheat

What: Don’t hold iron on joint for more than 3-5 seconds.

Why: Can damage PCB, lift pads, or damage switches.

Tip 5: Let Joints Cool

What: Don’t move or touch joints immediately after soldering.

Why: Movement while cooling creates cold joints.

Tip 6: Practice First

What: Practice on spare PCB or practice kit before soldering expensive keyboard.

Why: Build confidence and muscle memory.

Budget ($30-50)

Yihua 908D:

  • Adjustable temperature
  • Decent quality
  • Good for beginners

Mid-Range ($50-100)

TS100 / TS80P (Portable):

  • USB-C powered
  • Compact, portable
  • Fast heating
  • Popular among keyboard builders

Pinecil:

  • Similar to TS100
  • Open-source
  • USB-C powered
  • $30-40

Premium ($100-200)

Hakko FX-888D:

  • Industry standard
  • Excellent temperature control
  • Reliable, long-lasting
  • Best for serious hobbyists

Weller WE1010NA:

  • Professional quality
  • Digital display
  • Precise temperature control

Alternative: Build with Hot-Swap Sockets

Mill-Max Sockets

What: Hot-swap sockets you solder into PCB, then insert switches without soldering.

Process:

  1. Solder Mill-Max sockets into PCB switch holes
  2. Insert switches into sockets (no soldering!)
  3. Swap switches anytime

Pros:

  • Converts any PCB to hot-swap
  • Switch flexibility
  • One-time soldering effort

Cons:

  • Sockets cost $0.30-0.50 each ($30-50 per keyboard)
  • Still requires soldering (sockets)

Takeaway

Soldering is a learnable skill: Start with practice, build confidence, then tackle your keyboard.

Essential skills:

  • Heat joint properly
  • Apply right amount of solder
  • Inspect joints for quality

Tools matter: Invest in a quality temperature-controlled iron. It makes a huge difference.

Start simple:

  • Practice on scrap PCB or switch tester
  • Build 40% or macropad first (fewer switches)
  • Graduate to full keyboards

Hot-swap is valid: You don’t NEED to solder. Hot-swap keyboards are excellent. But soldering unlocks ultimate customization.

Next Steps