How to

Building your own model rail electronics DIY kit is not only rewarding — it’s also a great way to improve your electronics skills. To achieve the best results, it’s important to work in a structured and organized way: plan your steps, prepare your components and follow a consistent soldering workflow. With the right tools and preparation, most DIY soldering projects are perfectly achievable, even for beginners.

• Minimum tools required
• Recommended tools (nice to have)
• Preparing your project
• Step-by-step soldering technique
• After soldering
• Safety guidelines
• Final advice

Minimum tools required

With the following basic tools, you can assemble nearly all through-hole DIY kits. Having a dedicated, organized workspace helps you maintain a structured workflow.

Soldering iron (25-60W)
– Preferably temperature controlled.
– Fine tip suitable for electronics.
– Recommended temperature: 330–370°C (625–700°F).

We can recommend the Atten brand of soldering stations. A good start is the Atten ST-60. With a power consumption of 60 Watts it can solder at temperatures from 150 ~ 450 °C. This is a passive soldering iron meaning the tip itself fits over the heating element. It takes a short time for the iron to reach the desired temperature. If you really want a top soldering station, the Atten ST-909 is what you will like. This is an active soldering station with a power consumption of 90 Watts. It can solder at temperatures from 200 ~ 500 °C but the tip will heat up in seconds as the tip includes the heating element.

Solder
– 60/40 Tin-lead solder (easier to work with but more difficult to get), 0.8-1.0mm.
– Lead-free solder (requires slightly higher temperature), preferably with flux core, 0.8-1.0mm.

Side cutting tool
For trimming excess component leads after soldering. You can get this side cutting tool in the shop.

Multimeter
Essential for checking continuity, measuring voltages and verifying resistor values. You don’t need to buy a top of the bill multimeter. Even the cheapest digital multimeters like the DT-830B will be sufficient. Most of these smaller versions you need to set it to the correct range to measure. The more advanced multimeters have auto range functionality so you only need to select the category you want to measure. You can get those as well for around € 20.

Good lightning
A well-lit workspace is essential for clean and accurate soldering. A desk magnifying lamp makes precise soldering even easier. You can get these for around € 24 from the well known Chinese online shops.

Tip cleaner
Use a sponge for a passive soldering iron to clean the tip when needed also to ensure proper heat transfer. Use brass wool for an active soldering iron.

Recommended tools (nice to have)

PCB holder
Keeps the circuit board stable while soldering and you can easily rotate the circuit board during the soldering activities. You can get this PCB holder in the shop.

Heat resistant soldering mat
A heat resistant soldering mat protects your desk for accidental burns from the soldering iron. Available in different sizes and versions.

Multimeter test hook clips
The easiest way for measuring resistors and other components.

Component bend tool
Easy bending resistors and other components at the exact space for positioning on the circuit board. This bendtool is available in the shop but you can also download the STL-file and have it 3D printed yourself.

Preparing your project

Preparation is key for a structured workflow. Taking time to plan before you solder prevents mistakes and saves time.

Step 1: Check all components
Identify all components with the building instructions of the project.
Verify resistor values using a multimeter and position them in the correct order.
Pay close attention to components with polarity: leds, electrolytic capacitors, diodes, resistor arrays, integrated circuits and integrated circuit sockets.

Step 2: Plan the assembly order
A rule of thumb is that you work from low profile to high profile components. Follow our building instructions which are already in the optimal order. Group similar components together. Lay components out in the order you will solder them.

Step 3: Insert components
Some components, such as resistors and diodes, can be soldered more easily from the top side of the circuit board, but many need to be soldered from the bottom side. Slightly bend the leads outward to hold the components in place before soldering, or use a small piece of tape to keep them positioned. Solder one lead first and check the vertical alignment—for example, of LEDs—before soldering the other leads of that component. Once additional leads are soldered, it can be difficult to reposition the component. Also, do not always cut the leads right away. Sometimes you can use them to correctly position the next component.

Step-by-step soldering technique

Step 1: Clean the tip
Before soldering each joint, clean the soldering tip using a damp sponge or brass wool depending on your type of soldering iron.

Step 2: Heat both pad and lead
Place the tip so it touches both the solder pad and the component lead.

Step 3: Apply solder
Feed solder into the heated joint (where pad and lead meet).
The solder should flow smoothly around the lead.

Step 4: Remove solder and iron
Remove the solder wire first, then the iron. Aim for a total soldering time of 2–3 seconds per joint.

Step 5: Cooling
Let the joint cool and avoid the need to blow.

Step 6: Maintain consistency
Use the same approach for all joints. Structured, repetitive motion produces cleaner results.

What does a good solder joint look like and what are common mistakes to avoid?

✔ Smooth and shiny
✔ Slight cone shape
✔ Not too much solder
✔ No bridges to adjacent pads
Result: A!

❌ B: too much solder
❌ C: too little solder → weak connection
❌ D: cold solder joints (dull or grainy appearance)
❌ E: heating too long → PCB may damage or component breaks
❌ F: contact bridge creating a short

Tip: Keep your workflow structured — check each joint before moving on to the next.

After soldering

Step 1: Visual inspection
– No solder bridges?
– Components mounted correctly?
– Polarity correct?

Step 2: Electrical check
Use a multimeter to:
– Check for short circuits between + and –.
– Verify continuity where needed.

Step 3: Initial power-up
Power the circuit using a current-limited power supply.
Structured testing prevents accidental damage.

Safety guidelines

• Work in a well-ventilated area
• Never touch the soldering tip
• Do not leave the soldering iron unattended
• Wash your hands after using lead-based solder

Maintaining a structured workflow also helps keep your workspace safer.

Final advice

Soldering is a skill that improves quickly with practice. By working in a structured and organized way, carefully checking each step and taking your time, you’ll achieve professional results — even as a beginner.

If you have questions about any of our DIY kits, feel free to contact Model Rail Electronics — we’re happy to help.