If this is the case, how does one know what temperature to set this iron? Is this variable temp option really used? I suppose I'm seeking an education for this new toy.
650°F to 750°F will handle 99% of you hobbyist soldering needs.
For apprentices and novices (at soldering), variable temperature is BAD NEWS.
Soldering relies on a number of variables that needs to be properly balanced.
1. Solder Alloy formation (Sb/Tin-PB/Lead; RoHS/No-Lead). http://en.wikipedia.org/wiki/Solder
Tin/lead solders, also called soft solders, are commercially available with tin concentrations
between 5% and 70% by weight.
The greater the tin concentration, the greater the solder’s tensile and shear strengths.
Alloys commonly used for electrical soldering are 60/40 Tin/lead (Sn/Pb)
which melts at 370°F or 188°C and 63/37 Sn/Pb used principally in electrical/electronic work.
The 63/37 is a eutectic alloy
* has the lowest melting point (183°C or 361.4°F) of all the tin/lead alloys; and
* the melting point is truly a point — not a range.
2. Soldering Techniques and Tip Selectionhttp://en.wikipedia.org/wiki/Soldering
Soldering is a subset of the larger techniques that include Brazing and Welding.
SOLDER IRON TIP SELECTION:
Match the characteristics to the joint to the tip that will perform the work,
The Temperature is a SET ONCE step determined by below and Solder Alloy formulation.
1. PROFILE (Chisel, Screwdriver, Conical, Single Flat, Gull-Wing)
2. SIZE of TIP PROFILE (1/32" to over 1/4"), Hakko uses Metric measures, so convert as needed.
3. OVERALL MASS - Match the size and profile of iron tip to work.
OVERALL RECOOMENDATION for Thru-Hole and Point to Point wiring.
Screwdriver or Chisel Tip ; 1/16" or 3/32" size; Set station to 700 °F ;
Use a 60/40 or 63/37 solder with mild flux (Kester 44) of 0.031" to 0.020" diameter.
The 0.025" diameter for your solder is a good compromise,
if you are doing connector and fine PC board work.
ELECRAFT has soldering recommendations, on their web site, or Kit Builders.
By Tom Hammond, N0SS (sk)http://www.elecraft.com/TechNotes/N0SS_SolderNotes/N0SS_SolderNotesV6.pdf