The most important requirement in soldering is to have an iron that will maintain sufficient heat throughout making the joint. This is achieved by a combination of iron power (wattage) and size of bit (heat reservoir).

  The wattage will determine how quickly heat is replaced in the bit after it is removed from the joint. The size of the bit will determine how long sufficient heat will be available as you run the solder down the joint.

  A high wattage iron with a small pin point bit will be great for spot soldering but no good for running a seem joint.

  A high wattage iron with a massive bit would meet the criteria but would be clumsy and not get into the corners. So it is a case of getting a compromise and most modellers acquire a range of irons for different jobs.

  If you were only to buy one iron in you lifetime then I would recommend a Weller 40 Watt soldering iron (Squires Code 186-041). This has a 6mm diameter removable copper bit. The bit is shaped like a screwdriver and has a bright coating of solder (tinned).

  This combination of iron and bit shape is ideal for running fillet joints and has a good reserve of heat that is so necessary for soldering small parts onto large components. Note the shape and condition of a new bit as this won’t last long and will need restoring back to this condition.

  It is important to keep the bit clean and in good condition as you work. Get a soldering iron stand containing a damp sponge as old oxidized solder is wiped off on this before picking up fresh solder for each joint. If you haven’t made a joint for some time you may find that a hard black crust has formed on the bit. Remove this with a brass wire brush (suede brush) and then feed some multicore solder onto each side of the bit to restore a bright surface (referred to as wetting or tinning the bit).

  After about 8 hours use you will find the bit is in poor condition with holes and a ragged edge. File the bit back to its original shape using a hand bastard file and then polish the surfaces on emery cloth. Coat the bit with Fluxite Soldering Paste (traditionally used by plumbers, Squires code FLU100) and this will prevent the bare copper oxidizing as the iron heats up.

  Then feed multicore solder onto the bit to form a generous coating and leave to bubble away for a couple of minutes before wiping the excess off to give a bit almost as good as new.

  Don’t waste your money buying long life bits as with experience you will prefer to file a copper bit to a shape and angle that suits you best.

  A Weller 80 Watt soldering iron (Squires Code 186-081) is also a useful addition to the toolbox for the occasional heavy jobs like soldering bearings into heavy frames or when laminating three or four layers of brass together. But you will find these jobs on the more advanced and sophisticated kits in the range.

  A smaller Antex 25 Watt iron (Squires Code 185-584) with a 3mm screwdriver bit (Squires Code A1/XX54) is very useful for small assemblies and detail work such as handrails, but will have insufficient heat reserve for main assembly work.

  The Antex has a plated iron bit and after a little use with 145° solder a grey oxide appears on the bit that will prevent you from picking up the solder. Touch the bit to some multicore solder and it will flash over the bit (known as wetting the bit) so that you can continue picking up 145° solder.

  I have found no problems with mixing the two solders in this way. You will find that this iron is ideal for electrical work such as wiring up the layout and soldering electrical wire to the side of the rail using 60/40 electrical solder.