There is lots of advice on the web related to choosing the best soldering iron, but most of this advice is related to electronics
and soldering PCBs. Some boat
owners do a little of this, but most marine
soldering jobs does not involve a circuit board or small electronic components.
Soldering irons that could be used for marine work
vary from $15 to many hundreds of dollars. Lets have a look at the range, increasing in quality:
Non-temperature controlled mains powered iron:
This is by far the most commonly used soldering iron on a boat. When the iron is plugged in the tip gets hotter and hotter. After turning on they usually take one to two minutes to heat up to a temperature where they will melt solder.
Unfortunately, if the tip becomes too hot the flux rapidly burns away and this produces a poor joint and means a more aggressive flux must be used. The higher temperature is also more likely to damage wire insulation. Any electronic components in close proximity to the joint can also be damaged.
This type of soldering iron uses an indirect form of tip heating
. This is why they take so long to heat up, and more importantly, as the iron is applied to the joint, the tip will cool and even a relatively high wattage iron will struggle to transfer enough heat, so the joint can be too cold, as well as too hot.
If you match the size of the iron to the job, the above problems are reduced. So a 20-30w iron is needed for electronics or fine wires, a 50-60w iron for most marine wiring
and 80w or greater for larger joints or wires.
There are other difficulties. The poor heat transfer means the handles become hot unless they are seperated from the tip by a considerable distance. Delicate work is harder, a bit like trying to write by holding the end of the pencil rather than near the tip.
to the soldering iron is not silicone and if the iron contacts the wire it will melt and this wire carries mains power. They also do not typically come with a soldering stand.
Temperature controlled mains powered iron:
This has some circuitry that stops the heating when the tip reaches the set temperature. This solves some, but not most of the above problems.
Temperature controlled solder station:
These use a base station typically powering the iron itself with around 24v. They are a good solution for electronic work, but they still use an indirect form of heating and measuring the temperature of the tip. The heat power is limited, which is not a problem for fine electronics, but most models do not quite have the heat generating ability to ideally solder wires that are frequently encountered in the marine environment
. They are still a good option for light work. They are more pleasant to use with features such as silicone power cords and are usually better balanced, although your fingertips are still often a long way from the work making fine control difficult.
Temperature controlled solder station using so called direct heating:
These use a different method of heating and measuring the temperate of the tip. They transfer much more heating power so will solder larger wiring while still being temperate controlled. They are ideal on a boat, but they are the most expensive option. They have enough power that generally one iron will do all jobs from very fine and delicate electronic work all the way up to reasonably large wires and devices that act as large heat sink.
There are some cheaper DIY
options using this technology. The TS100 is one such product. Typically you provide your own power supply (such as an old laptop
brick) and while less capable than the best irons, it has many of the advantages of the newer technology.
Solder gun: These are similar to a non-temperature controlled mains powered iron and have similar drawbacks. They are available in large sizes (up to 300w). The trigger mechanism provides some manual control of temperature.
or butane powered irons: These can be useful for obvious reasons on a boat.
Some have converted the TS100 to battery
power (using lithium cells) and this is arguably the best portable solution.
A good guide to the quality of the technology used in a solding iron is the heating time. From a cold start, the time taken before the iron is hot enough to melt solder will be 1-2 minutes for a mains powered soldering iron, and 30 seconds to a minute for a reasonable solder station. For the best direct heating irons the time is reduced to a few seconds. Waiting even a couple of minutes for an iron to heat up is not a big deal, but a long time to transfer heat to tip means the iron will struggle to transfer heat when the tip is cooled down from larger heat sinks such as heavier wiring.