Solder is useful when connecting wires in lamps/fixtures.  However, soldering in small spaces can be tricky because of the fumes and because of the heat.  Exercise extreme caution! 

Solder Tabs provide an alternative to the soldering iron.  Tabs are wrapped around the joined wire ends then heated with a lit match.  Again,exercise extreme caution

• HEADACHE AVOIDANCE TIP:  NEVER RUSH OR SKIP ELECTRICAL INSULATION  

Electrical insulation keeps current flowing where it belongs, helps maintain a tight wire-to-wire contact, can help securely anchor to the circuit foundation, and serves as a line of defense against environmental conditions.
 
The raw ends of  wires in small scale circuits, by nature, are always very close to each other.  This makes small scale wiring vulnerable to unexpected shorts that result from faulty insulation materials, insulation fatigue, and poor installation methods.

Once wiring is sealed into a structure or under finishing materials, circuit failure becomes more difficult to diagnose and correct.  Doing it right the first time is the best time saver.

Humidity is one of the sneaky enemies of hobby wiring.  If your project will be, or might ever be, subjected to high humidity choose an insulation material that will reliably block moisture.

Moving a dollhouse or diorama equals a small scale earthquake.  Plan your insulation to protect portable projects.

If your project will be exposed to extreme temperatures (such as un-temperature controlled storage)choose an insulation that will not deteriorate in that circumstance.

• HEADACHE AVOIDANCE TIP:  PRACTICE INSTALLATION TECHNIQUES ON WIRE SCRAPS.     
• WARNING:  Those who skip this exercise often go straight to Learning Foul Language;  Lesson One.

Electrical Tape is often too bulky for scale model and hobby wiring but can be used when hidden wiring chambers are built into the structure.  Some brands are more pliable than others.  Some brands use more reliable adhesive than others.  Use the smallest piece possible to avoid extra bulk and make certain the adhesive is adequate.  Always test a sample of the tape to see how well it performs.  I've used tape that worked great at the time of installation but popped off after a few days or weeks.

Heat Shrink Tubes are a good choice for small projects.  Heat Shrink Tubes must be strung on the wire before the wires are joined.  The wires should be twisted tightly before sliding the tube in place.  The junction should be held  securely while the tube is being heated. 

Liquid Insulation is applied with a brush, remains pliable, and conforms with the space available.  Before applying, make certain that the wire ends are tightly twisted.

Silicon Sealant is applied with a toothpick or craft stick and can be smoothed to seal wires into notches cut to hold wires.  It remains pliable and easily conforms to the space available.  Make certain that the wire ends are tightly twisted before applying.

Color Coded Tape Wire Junction

Tape wire contains two strips of copper with identical properties.

One strip provides the electrical path from the power source to the fixtures.  The other provides the return path from the fixtures to complete the circuit.

Color coding was added to avoid confusion and potential wiring mistakes.  One strip is copper color and the other is gray.

• SAFETY TIP:  ALWAYS CONNECT SAME COLOR TO SAME COLOR

NOTE:  Earlier tape wire was not color coded.  Those using non-color coded tape wire might want to use a Sharpie or some other permanent color marker to identify which wire is conducting electricity toward the fixtures or which is conducting it  away. 

 STRIP-TO-STRIP USING BRASS BRADS
Tape wire seals the conducting strips between an adhesive layer and a clear layer of protective insulation.

Brass brads inserted at the junction provide the necessary metal-to-metal contact between the copper strips when the wiring foundation will accept nails.  Eyelets can also be used (see below).
The brads become a part of the circuit.  Just like wire or strips, the brad size must to be sufficient to carry the desired amount of electricity.

The standard is 2 brads per junction.
If a larger load is to be carried an extra brad can be added at each junction to make certain the circuit capacity is adequate.



A Brad Placement Tool is the easiest way to install brads.  The brad is held in the lower jaw.  The upper jaw serves as stabilizer during positioning the brad in the pilot hole, and as a push hammer for the first stage of installation.

1. Mark brad placement sites.  Make certain that you are joining same color to same color.
2. Make pilot holes with a pin or needle.
3. Load the Brad Placement Tool with one brad and close the jaws to secure the brad in a stable position.
4. Place the tip of the brad in the pilot hole, keeping the brad as straight as possible.
5. Push into the surface as far as possible.
6. Remove the tool.
7. Using a small hammer or standard punch hammer, tap or push brad to a flush position.
8. Coat the surface with insulation.

Strip-to-Strip using Brass Brads

Brass eyelets can be used instead of brads to join wire tape.  Only one eyelet is needed at each wire junction.

Eyelet Placement

1. Mark eyelet placement sites.  Make certain that you are joining same color to same color.
2. Make pilot holes with an awl or small drill bit (slightly smaller than eyelet diameter).
3. Position the eyelet in the hole with stem down.
4. Using a small hammer, tap to a flush position.
5. Coat the surface with insulation.
   

• NOTE:  Electricity is conducted through the contact of the tape wire against the stem of the brad and the eyelet.  However, the heads of both brads and eyelets are live and uninsulated whenever the circuit is connected to a power source.
• SAFETY TIP:  To avoid unexpected short circuits and shocks, apply electrical insulation to the exposed surfaces.

The circuit principle is the same for round wire as for tape wire:y
     One wire serves as the electrical pathway to the fixtures.
     The second wire services as the return pathway.

•  SAFETY TIP:  Use a different color for each pathway.  When only single color wire is available, add your own color coding.

Alligator Clip used as wire stripper

1. Strip wire ends.  Using a wire stripper tool or an alligator clip, strip the insulation off the ends of the wires to be joined.
2. If using a Heat Shrink Tube as insulation, slide the tube onto one of the wires.
3. Twist the wire ends together to make as much contact as possible.
4. Optional:  Solder can be used to coat the joined wires but is not necessary.
5. Seal the joined ends with electrical insulation.

• TIP:  Oxidation can prevent the flow of current. Stripped wires that have been exposed to the air for a long period of time may need to be sanded lightly to remove oxidation before being twisted together.  

Brad or Eyelet Method

1. Partially inserting brads or eyelets into the tape wire (see instruction above).
2. Wrapping the round wire around the brad or eyelet.
3. Press or tap the to make brad or eyelet flush with surface.
4. Apply electrical insulation.

Slit or Splice Method

1. Make a small slit down the center of each tape wire using a craft knife.  
2. Cut from slit to edge of tape to create a flap.
3. Lift tape wire flap.
4. Lay stripped wire ends under the flap, spreading the bundle for maximum contact between the stripped wires and the cut edges of the tape wire.
5. Put tape wire flap back in position.
6. Apply electrical insulation.

This topic will be explored in more depth when dealing with specific projects.