Best Marine Soldering Practices

[onewadd]

Originally Posted by Lake-Effect

I know you're expecting this: where on a boat is it advisable to use solder for making a high-current connection? I don't know of one, nor of any situation where soldering would produce a better high-current connection than mechanical means.


ABYC and all that...


I don't have any issues with carefully soldering lower current and signal connections, as long as all the mechanical problems caused by soldering (brittleness, loss of flexibility) have been addressed.

What he said

[Sailnav]

What about "solder-seal" tubular connectors?

https://www.youtube.com/watch?v=7ME3FPuZ6Zw

[roland stockham]

Thanks for that Noelex, very useful. Couple of questions for you. Main problem I get with heavy cable, 2g and above (which I do like to solder) is that the heat required to get a good joint damages the insulation unless you cut it back rather further than I want to. Know any tricks to reduce this?
Second one is on annealing. I was taught to quench the joint in water to anneal the copper and stop it cracking under vibration. Do you recommend this? I am not sure what it does to the solder.

[thinwater]

Originally Posted by Sailnav

What about "solder-seal" tubular connectors?

I've tested some of these. They can be good, but they can also be awful, depending on the solder used, the tubing, and other design factors. Some are worse than just twisting wires together.


I'm not sayin' there are not good ones, but don't believe all you read. After testing, I either crimp or solder manually and heat shrink.

[GordMay]

I'm not certain, but I think that 3M (for instance) withdrew their version of the solder seal heat shrink connectors/terminals from the market. They were unreliable.

[S/V Illusion]

Originally Posted by roland stockham

Thanks for that Noelex, very useful. Couple of questions for you. Main problem I get with heavy cable, 2g and above (which I do like to solder) is that the heat required to get a good joint damages the insulation unless you cut it back rather further than I want to. Know any tricks to reduce this?
Second one is on annealing. I was taught to quench the joint in water to anneal the copper and stop it cracking under vibration. Do you recommend this? I am not sure what it does to the solder.

The easiest way to avoid heating the insulation is to clamp a plier or vice grip on the cable which will conduct some of the heat off the cable.

As fo "high current" applications, the myth they necessitate crimps is hard to die. In reality, bad (I.e., high resistance) connectionon low current bad connections can produce heat hot enough to burn - this is true regardless of how the connection is made. So using crimps on high current work isn't advisable.

You can't tell if a crimp is good but you can see a bad solder connection.

[Locquatious]

In electronics manufacture there is a drive to RoHS compliance which would entail using Pb free solder. These are higher melting solders. I had to solder leads onto the studs of bat switches. I started getting failures in the switches where the studs became loose after soldering on the wires. This ruined the time in use of the switches.

The switch manufacturer recommended maximum soldering tool temperatures and maximum soldering times (<6 seconds), but I found that I could not both heat the wire and the solder studs using Pb-free solder within the temperature and time constraints. I had to return to using leaded solder.

Take care what you are soldering to when using the higher melting temperature solders.

[noelex 77]

Soldering iron:

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.

The wiring 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.

Other options:

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.

Battery 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.

[Dave_S]

I was always taught where there is vibration to use 3 x lengths of heat shrink all differing lengths to create a progressive flexible bend. The intention is to disperse any movement over a greater area so the flexing doesn't occur at one point, causing fatigue of the connection.

Also some heat shrink is designed to create a water/air type seal.

[kmacdonald]

The best advice for soldering is "don't do it," crimp instead.

[hzcruiser]

Originally Posted by roland stockham

Thanks for that Noelex, very useful. Couple of questions for you. Main problem I get with heavy cable, 2g and above (which I do like to solder) is that the heat required to get a good joint damages the insulation unless you cut it back rather further than I want to. Know any tricks to reduce this?
Second one is on annealing. I was taught to quench the joint in water to anneal the copper and stop it cracking under vibration. Do you recommend this? I am not sure what it does to the solder.

One way to preserve the insulation would be to cool it down while soldering, e.g. with a bit of freeze spray, but that would also suck the heat from the copper. In the end, the only way I can see it is to add maybe two or even three different sized shrink tubes over the cable first, then slide them over the now exposed copped and shrink them in place, one by one.


I thought annealing would only happen if the metal is glowing hot, not at soldering temps?

[hzcruiser]

Originally Posted by thinwater

I'm not sayin' there are not good ones, but don't believe all you read. After testing, I either crimp or solder manually and heat shrink.

Agreed. Apart from them being fairly expensive, I'm always reluctant to crimp with the insulation already on. Chances to puncture it are too high.

[Jim Cate]

Re the annealing question: You don't anneal something by quenching it. Rather you let it cool slowly. For copper wires, their high thermal conductivity means they will cool fairly quickly once t he heat source is removed, but in my experience they remain flexible outside the actual soldered area.

A practical way to anneal copper things like gaskets and crush washers (when replacement is not possible) is to use a candle or acetylene torch to soot them up. Then heat just until the soot burns off, then set on a non heat conductive surface and let cool. They will be in a soft, annealed state.

Jim

[westsailwill]

Originally Posted by noelex 77

Soldering iron:

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.

The wiring 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.

Other options:

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.

Battery 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.

Thanks so much for all the really terrific and helpful info. If it wouldn’t be too much to ask, some name brand and model recommendations on your top three picks of all round best irons would be greatly appreciated by many.
Cheers,
Will

[sstuller]

As far as I know the Coast Guard does not allow soldered connections on inspected vessels. They must be crimped.