The hand piece has a collet for securing a carbon tip.
Loosen the knurled nut on the collet just enough to allow
you to insert the carbon tip. Insert it as far as it will go and
tighten the knurled nut to secure it in place. The carbon tip
can be easily shaped with a file or sandpaper. Most people
form a chisel-shape.
Next, connect the ring terminal at the end of the wire from
the hand piece under the wing nut labeled “Hand Piece.”
Connect the ring terminal of the power clip under either the
“High” (for large parts) or “Low” (for small parts) wing nut.
Tighten the wing nuts securely.
Getting Started
Plug the power unit into the “piggyback” connector on the
footswitch cord. Then plug the footswitch cord into a
grounded outlet. Electrical power will be applied only when
you depress the footswitch.
All soldering requires the metal pieces to be clean. Good
solder joints start with shiny metal pieces that are free of
oxidation. Application of soldering flux inhibits oxidation as
the metal heats up. After cleaning and fluxing, position the
two parts to be soldered in their final configuration.
Connect the power clip to one part. Touch the carbon tip of
the hand piece to the other part near the joint. Depress the
footswitch, allow a few seconds for the parts to heat, then
apply solder to the joint. Remove pressure from the foot
switch as soon as the solder flows into the joint. Continue
to hold the carbon tip against the joint until the solder cools
sufficiently to harden.
Making Solder Joints
Before performing any inspection, maintenance, or
cleaning of the Resistance Soldering Unit, make sure that
the power cord is unplugged from the wall socket.
Repairs should be carried out by only a qualified service
technician.
Maintenance and Cleaning
To understand how the Resistance Soldering Unit (RSU)
works, you must first understand the difference between
electrical current and voltage:
Current is the volume of electricity flowing through a part
(measured in amps).
Voltage is the electrical pressure pushing the current
though the part (measured in volts).
If enough current passes through a piece of material
(even at low voltage), the piece will get hot. If the current
is sufficient, the material will get hot enough to melt solder.
Take away the current and the soldered parts will cool. At
the place where two parts to be soldered together touch
each other, heat will develop faster than at other locations.
Thus, already-assembled parts won’t fall apart before the
new joint is soldered.
The RSU supplies sufficient electrical current to melt solder
when used on smaller sized materials, as is typical for
assembling scale models. Even though the output current
is high, the voltage is quite low, so the danger of electrical
shock is virtually eliminated.
Since the parts to be joined are heating internally, there is
no need to depend on the slow transfer of heat from the tip
of a soldering iron or gun; therefore, an RSU heats parts
quickly…so quickly that adjacent parts won’t fall off. Shut
off the power, and parts cool below soldering temperature
rather quickly, as well (but, be careful…they’re still too hot
to touch, including the carbon tip of the hand piece!)
The RSU needs two connections to the material for current
to flow: One is provided with a power clip; the other is
provided through a hand piece with a carbon tip (we use a
carbon tip so that solder won’t stick to it). The power unit
has two power taps for the clip: one for low power for
delicate parts; one for high power for heavy parts.
The power is turned on and off using the included foot
switch.
Resistance Soldering – How It Works
T H E S M A L L T O O L S P E C I A L I S T S
340 Snyder Avenue, Berkeley Heights, NJ 07922
www.micromark.com • Tech Support: 908-464-1094, weekdays, 1pm to 5 pm ET • [email protected]
