Also for review and input...
==Electric Irons=There are several types.
===Standard electric iron==The electric iron is the favoured tool for all electrical work. Its
slow to heat up but maintains a fairly steady temperature, and is
instantly ready for all joints after the first.
===Thermostatic electric iron==Thermostatic irons heat up faster, and maintain ideal temperature more
accurately and consistently. They maintain and recover temperature
much better with large joints.
===Boostable electric iron==These non-thermostatic irons have a boost button that can be pressed
to double output power. Manual control of the button enables soldering
of larger pieces and rapid repeat soldering. These irons were the
forerunners of the automatic thermostatic types.
===Low voltage iron==24v irons can be run from a [[Lead acid battery|car battery]], [[Nicad
battery|cordless tool battery]], laptop battery or even series [[Zinc
carbon battery|6v lantern batteries]], as well as a mains power
supply. The availability of affordable gas irons has reduced the need
for this trick.
Thermostatic low voltage irons can be run from voltages somewhat above
or below ratings. Half rated voltage is about the bare minimum for TCP
irons, making a car battery usable. Non thermostatic types have a
narrow window of voltage, and don't function ok on the wrong voltage.
Standard irons use around 25w, so a [[Nicad battery|cordless tool
battery]] can deliver in the region of 1 - 2 hours use.
===Cold heat iron==The 'cold heat' soldering iron passes several volts through the
resistive tip only when in contact with copper or solder. Performance
is poor, and the voltage used is enough to kill some electronics.
===Soldering gun==These heat up in around 12 seconds, but the reheat time is repeated
with every joint. The tip temperature changes widely during use,
adding further skill requirement and difficulty for the beginner.
Soldering guns have short duty cycle ratings that are barely adequate
for work, complicating and slowing work down further.
==Other soldering tools=The other available soldering tools are listed to explain all the
===Melting pot==In industry some soldered joints are made using a melting pot. The pot
holds a quantity of molten metal, requiring certain safety
precautions. This is not an option recommended for home use. When used
these should be screwed to a heavy bench to minimise risk of severe
===Gas soldering iron==Gas irons are a cordless option. The heat is not as well controlled as
electric irons, which can sometimes lead to overheated tips or patchy
===Gas blowlamp==Gas blowlamps are used for [[plumbing]] soldering. They're unsuitable
for electrical joints.
===Miniature gas blowlamp==Miniature gas blowlamps the size of a fat writing pen are available.
Low cost has made them popular. These have their uses, but aren't
great performers for most soldering work. They're well suited to
soldering tinplate containers together, and desoldering where
indiscriminate heat is acceptable (ie not for electronics). Many of
these tools are prone to flaring, which is a safety issue.
===Paraffin/petrol blowlamp==Liquid fuel blowlamp designs date back to the 1800s, and use a
pressurised tank of heated highly flammable fuel, which is boiled
within the lamp. These are cheaper to run than gas, but have a poor
safety record. The mains risks are explosion, spraying burning fuel,
and the results of being knocked over.
===Pre-war irons==Rarely irons are seen which are placed on a gas ring to heat them.
These date from the 1930s and earlier. There's probably no job for
which they could be recommended, but since they are technically
soldering irons, beware on ebay.
==Choosing an iron=I've used everything from industrial soldering stations to salvaged
junk, and I've yet to meet an iron that couldn't make a decent joint.
So the choice is not a critical one, as long as unsuitable types are
Not ideal for general electrical work:
* high power irons above 35w
Irons below about 20w
* flame lamps with no soldering tip
The worst irons don't have replaceable tips, with the heater wire
wound on the metal rod that forms the tip. Although not best practice,
in reality such tips are still capable of decades of use.
The best irons are thermostatic. These are useful if you do a lot of
soldering, or wish to solder larger pieces. Next best are boostable
irons. Availability of assorted tip shapes can be useful if you wish
to do the less types of work.
See also the next section...
===Used irons==Used irons from boot sales etc are liable to have electrical faults.
Since a soldering iron is something you wrap your hand round in use,
electric shocks can become fatal, and the iron should be checked to
ensure the wiring's ok, the cordgrip secure, and ideally the
insulation should be tested.
Very old irons tend to have a lot of corrosion at the business end.
Some people remove the tip and wire brush the corrosion off, then coat
the part that will be reinserted with silicone oil. This prevents the
tip jamming in the iron from further corrosion.
==Tips=Irons use 2 common types of tip: plain copper and iron plated copper.
Steel tips are also occasionally seen.
===Tip types======Plain copper===Older irons and budget irons use plain copper tips. These gradually
wear down in use through oxidation and dissolution. When the tip has
worn out of shape its simply filed down back to the desired shape.
Plain copper tips are cheap and can be filed or ground to any desired
shape. The filings contain lead compounds, and should be disposed of
rather than left to litter house or garden.
====Plated===Plated tips are common on better newer irons. These tips wear much
less than copper ones, as long as the plating lasts. Don't file these
tips, it removes the plating.
Eventually the plate wears through. Once this happens they're no
different to plain copper tips, and can be either treated like a plain
copper tip or replaced.
====Steel===Steel tips are occasionally seen at the bottom end of the market. Like
plated copper, these don't dissolve in the solder over time. However
they have poorer thermal capacity than copper tips, so they lose
temperature more on large joints and can't do as large joints.
===Tip cleaning==A wipe on wet denim or wet cellulose sponge removes most muck build
up. Cleaning the tip now and then makes soldering easier and more
Cellulose sponges are easily spotted by the fact that they set hard
when they dry. Small cellulose sponge pads are available from the main
soldering iron manufacturers.
===Tip shapes==Various tip shapes are available. The 2 most popular shapes are cut
bar and pencil.
====Cut bar===Cut bar tips are round section bar cut across at an angle, forming an
oval flat area. These are very versatile, good for almost all tasks,
and are recommended for all but SMD work (surface mount electronic
====Pencil===Pencil tips, like an elongated pencil tip are now very popular. These
perform rather better for tiny work such as surface mount components,
about the same for general PCB soldering, and less well for most other
tasks. They're a good choice where surface mount components are
included in the work to be soldered. Where smds won't be soldered the
cut bar is probably better overall, though opinions and preferences do
====IC tips===Big rectangular tips are occasionally seen that will contact all pins
on a DIL IC at once. Unfortunately for desoldering ICs these aren't
====Oddballs===Various other shapes are also seen. The cheapest irons just use an
ordinary steel nail; even these crude tips perform adequately in
Perhaps the oddest tip shape I've seen was a round ended round bar
slit up the middle. It turned out to be a pin from a 15A plug.
====Selections===Better quality irons have a selection of available tips that can be
changed as wanted, but each tip must be left to cool down before
removal, and the new one must heat up before work. Its more realistic
to use separate irons each fitted with its own tip type.
====Flat plate===Probably the least common are the flat plate tips. These are used for
cutting and welding plastics, something not that often done with
soldering irons - not deliberately anyway. When doing plastic work a
separate tip should be used for this, and not used for soldering.
Plastic work produces burnt muck, and soldering requires the absence
of such muck.
Irons should be run at lower temperature for plastic work. If run at
soldering temps they will burn nearly all plastics, and burnt plastic
fumes tend to be mildly toxic. Temperaure can be reduced with a
transformer or [[Droppers|dropper]].
===First use==On first use a soldering iron bit should be tinned. This means coating
it with solder as soon as the solder will melt on the tip. It the
solder wont initally wet the tip, just wipe it clean and try again.
===Tips for old irons===Some irons long out of production, such as the popular Henley Solon
irons, have no supplier providing new tips to fit. Sometimes there's a
modern iron that takes the same diameter tips, in which case you can
buy ready made tips. If not you can buy copper bar of the desired
diameter from a metal stockist. Round pin plug pins are sometimes
used, they come in several sizes in different plugs.
Copper, brass and bronze are all usable as tips. Steel can also be
used if necessary, but provides less thermal capacity, so will limit
the size of item that can be soldered.
==Mains leads=[[flex|PVC leads]] are often seen, but are only barely suitable for
soldering irons. High temps are encountered within the iron body, and
the hot bit usually melts through a pvc lead sooner or later.
[[flex|Rubber]] is far more durable. The best leads are silicone,
these don't eventually perish as rubber does.
==Holder=A holder is recommended for soldering irons to reduce the minor risks
of damage, burns, injury and fire. A holder simply keeps the iron in
one place. Ready made holders are available, or a bit of scrap is
easily bent to a suitable shape. The holder should have some weight
and stability to it to prevent it being dragged off the table or
turned over. A few irons have a hook on them, these can be hung on
==Retrofitting a boost button=Its possible to add a boost function to non-boost irons by rectifying
the mains and adding an electrolytic capacitor across the supply,
connected via a push switch.
Such a boost switch is used to recover from temp drops after soldering
large items. They aren't intended to raise working temperature above
Don't do this unless you know how to do safe work at mains voltages.
Wikis are publicly editable, so if you need to rely on advice you
should confirm any safety critical work elsewhere before proceeding.
The bridge rectifier should be rated 1kV, or a 600v bridge may be used
if 4 small capacitors are fitted across it. 250v bridges aren't
The boost capacitor must be connected with correct polarity, and
should be rated 400v. 250v capacitors are entirely unsuitable.
A small low current mains push switch is mounted in the iron handle,
and the mains lead is replaced with 4 core (the capacitor is too big
to mount in the iron).
A neon (with built in resistor in one lead) is connected across the
capacitor to show when boost is on.
A 3uF capacitor gives around 50% power boost with a 25w iron.
If you don't know how to build it from the information provided,
==See Also=* [[Special:Allpages|Wiki Contents]]
[[Special:Categories|Wiki Subject Categories]]