Best Marine Soldering Practices

noelex

noelex

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There are plenty of threads about soldering v crimping. Let’s just say both can produce great marine electrical joints, but even if you prefer crimping, soldering is a good skill to have. There are some joints and repairs that can only be done via soldering.

Boat electrical systems are becoming far more sophisticated. Techniques that produced perfectly acceptable results a decade ago are not necessarily satisfactory with the demands and high currents used on modern boats.

Soldering technique is all important, but this is very difficult to teach via forum posts. So I wanted to share a couple of posts about soldering equipment. Most boat owners try to solder with terrible equipment. With skill this can still produce acceptable results but good equipment does produce much better joints and as I have indicated above I think it is time to raise the standards of acceptable boat electrical work.
 
Solder:

The ideal solder for boat work is Leaded 63/37 with RMA flux. Preferably a known, quality brand.

Almost everyone using leaded solder on a boat will be using the much cheaper, older style, 60/40 solder, usually a no name brand, with an unknown flux.

63/37 solder is better. It has a higher tin content. The main advantage is this is a eutectic solder. Basically this means the solder only has one melting temperature. 60/40 solder has a temperature range. Once it is hot enough to melt, it has to cool down to a lower temperature before it solidifies. An joint movement during this solidification process will result in a poor joint. The instant temperature transition between a liquid and solid of 63/37 solder means there is less risk of a dry joint, particularly on a boat where soldering is not always in ideal conditions on a nice steady bench.

There are other advantages. The melting point of 63/37 solder is slightly lower, which reduces the risk of damaging components and wire insulation. It also produces a slightly stronger joint.

The next consideration is the flux used. The flux cleans the metal surface so the solder flows. It is basically impossible to solder without flux. The flux is most commonly incorporated into the solder wire itself, but you can use flux in paste form as well. The flux works by attacking the wire surface to remove the oxidation, but this also means the most aggressive fluxes are corrosive. Not ideal in a marine environment. Many cheap solders have reasonably aggressive fluxes, because this makes the solder easier to use. The flux can (and should be) cleaned away from the wire when you have finished soldering, but in a marine environment using as mild a flux as possible is better. The mildest fluxes are rosin based, but there are several grades of flux within the rosin family. The mildest is R followed by RMA (rosin mildly active) flux. The next slightly more aggressive flux is RA (rosin active). Following that there are many more very aggressive fluxe combinations. These can be useful for older, very oxidised wires, but you need to clean the joint carefully after using these.

Good solder wire will list the type of flux it contains. A simple solution is to buy 63/37 RMA solder and some tins of more aggressive flux in paste form for the more difficult cases.
 
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I'd suggest using solder with a 'no-clean' flux.
Other flux tends to cause corrosion and/or a sticky mess in the long run.
A flux pen is a useful tool.
https://uk.rs-online.com/web/p/solder-fluxes/4259379/
there are cheaper versions.

Avoid lead free solder if possible.
Use a decent, hot, powerful iron. You will do much less damage soldering something quickly with a good hot iron, than waiting for something barely hot enough which takes ages so heat spreads a long way.
Even soldering small stuff, I'm using a minimum of a 45W iron, but that's temperature controlled.
If the joint isn't running in 2 seconds, the iron is too small and/or too cool.
The tip stores heat, so don't use one too small for the job.

Be prepared to buy new tips.
A tip cleaner is useful, but can't work miracles.
https://uk.rs-online.com/web/p/soldering-station-accessories/5078698/
Don't leave the iron on more than necessary, the tip will oxidise. This is worse at the temperatures involved in lead free solder.

Don't breathe the fumes. I use a simple fume extractor. An old computer fan with guards is much better than nothing.
 
I have found leadless solder is very poor for good joints it tends make dry joints . leadless s solder also The old solder is much better.The new solder also tends to burn out the soldering iron tips
 
Are gas soldering irons a help or a hindrance? i have an Irodo gas one but I've never had the best of results with it. As a beginner would I be better off with an electric iron? A link to a decent beginners set up one would be good.
 
Depends what you want to do and depth of pockets.
I've used the cheap Anvil sets from Rapid Electronics for general work, you just have to turn the power up before doing anything heavy. And turn it down to stop it getting too hot and burning.
Not tried their digital versions.
Weller and Metcal are more professional, but 10x the price.
https://www.rapidonline.com/anvil-av-a48w-adjustable-analogue-48w-solder-station-85-5900

I have a bit of a collection of Weller TCP irons, they come up on ebay or I find them in skips in the industry and make 1 good one out of a pile of bits. I have a 12V DC version.

Spending other people's money I go for Metcal. As I do some surface mount work, it's not unusual to have £350 of soldering iron in each hand.....

I do have a butane soldering iron, a cheapie, it's OK for boat wiring, at least for small cables.

I also have a solder-gun which doubles as a hot knife, the instant heat (hot in 3 seconds ish) sort, that is good for some jobs.
https://www.ebay.co.uk/itm/100W-Sol...h=item2a759b4015:g:XsMAAOSwux5YM0~K:rk:2:pf:0
 
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.
 
fredrussell said:
Are gas soldering irons a help or a hindrance? i have an Irodo gas one but I've never had the best of results with it. As a beginner would I be better off with an electric iron? A link to a decent beginners set up one would be good.
Click to expand...

Depends on your expertise to some extent and what you're soldering. On the boat I have a 25 - 30 year old Portasol gas one with a couple of different sized tips which is sufficient. At home I have various sizes of electrical irons plus a monster which is heated with a Bullfinch torch or in a fire.
 
noelex said:
There are plenty of threads about soldering v crimping. Let’s just say both can produce great marine electrical joints, but even if you prefer crimping, soldering is a good skill to have. There are some joints and repairs that can only be done via soldering.

Boat electrical systems are becoming far more sophisticated. Techniques that produced perfectly acceptable results a decade ago are not necessarily satisfactory with the demands and high currents used on modern boats.

Soldering technique is all important, but this is very difficult to teach via forum posts. So I wanted to share a couple of posts about soldering equipment. Most boat owners try to solder with terrible equipment. With skill this can still produce acceptable results but good equipment does produce much better joints and as I have indicated above I think it is time to raise the standards of acceptable boat electrical work.
Click to expand...
I am not sure I agree with you!

With the development of new electrical systems there has also been a leap forward in connectors. Take NMEA 2000; basically plug and play. So I am sat hear scratching my head wondering where all these "solder only" repairs need to be done and where all these high currents have come from as everything is moving towards being extremely power lean. On big bits of kit, e.g. anchor winches, I want to have good solid connectors so I can remove kit to service (which reminds me that anchor winch needs a service).

Personally, I have a gas soldering iron, if fulfills all the soldering requirements I have onboard, also melts the ends of rope and is brilliant for caramelising the top of some deserts.
 
noelex said:
There are plenty of threads about soldering v crimping. Let’s just say both can produce great marine electrical joints, but even if you prefer crimping, soldering is a good skill to have. There are some joints and repairs that can only be done via soldering.
Click to expand...

What are these joints that can only be done by soldering ?

Boat electrical systems are becoming far more sophisticated. Techniques that produced perfectly acceptable results a decade ago are not necessarily satisfactory with the demands and high currents used on modern boats.
Click to expand...

What high current equipment needs soldering ?

I think it is time to raise the standards of acceptable boat electrical work.
Click to expand...

I agree, some of the things i see are pretty shocking. But, it's a very rare occasion i have to get the soldering iron out these days.
 
noelex said:
...Soldering technique is all important, but this is very difficult to teach via forum posts. So I wanted to share a couple of posts about soldering equipment..
Click to expand...

Many thanks for the posts, very useful and educational for an occasional solderer.
 
Sandy said:
...Personally, I have a gas soldering iron, if fulfills all the soldering requirements I have onboard, also melts the ends of rope and is brilliant for caramelising the top of some deserts.
Click to expand...
Ooh... far too posh for me and a whole different thread required I feel for the best gourmet burner... :)
 
We caramelise with a gaz torch from Aldi, which are good to free up Loctite as well. Would not be without one.

I too wonder where I have gone wrong, plug and play - no soldering - where are all the high tech demand I have overlooked. Expensive kit looking for an overfilled wallet (gullible owner?) and an application.

Jonathan
 
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Neeves said:
We caramelise with a gaz torch from Aldi, which are good to free up Loctite as well. Would not be without one.

I too wonder where I have gone wrong, plug and play - no soldering - where are all the high tech demand I have overlooked. Expensive kit looking for an overfilled wallet (gullible owner?) and an application.

Jonathan
Click to expand...
Can you solder with it? Everything on the boat must have at least two functions. The teapot fits under my hat!

I never realised Aldi had reached Australia.
 
PaulRainbow said:
But, it's a very rare occasion i have to get the soldering iron out these days.
Click to expand...

Paul, the subject of crimping vs soldering has been done to death on internet forums. There are passionate views on both sides. My own opinion is both methods can produce excellent connections if done correctly.

Unfortunately, both methods are sometimes done poorly, and not just by amateurs.

Going back to my first yacht, the maximium power draw from a single device was around 40w and there was a total of 5 circuit breakers. Skip to my new yacht and the maximium power draw from a single device has risen to many thousands of watts and we have ten times the number of circuit breakers.

Of course, there are still plenty of electrically simple yachts, but there is no doubt in my mind that the average yacht now has a significantly more complex and has a higher demand electrical system than was average a decade or more ago.

It is not unusual to see on modern yachts devices being asked to carry currents closer to their maximium rating. The humble AT fuse holder is one such example. On my first yacht such a fuse system would have been carrying less than 4A on any circuit, well within its capabilities. On modern yachts it is not unusual to see this fuse holder used in circuits that are much closer to the maximum rating. Pass 20A+ through a AT fuse holder and the connections need to be in good shape and stay in this condition even in the corrosive marine environment.

So the message I am trying to convey is the standards for whatever method you are using to make electrical connections needs to be high. Practices that were acceptable on less sophisticated electrical systems need to be revisited. This is equally true for both soldering and crimping, but the focus of the post was on the equipment used to make soldering connections. Technique is probably even more important with soldering but this is difficult to encapsulate in words.

Anyway, you asked for an example where the joint could only be done by soldering. A good illustration would have to be joining the radar cable on my last boat. The multitude of wires could have be joined with crimped connections and this would have been fine electrically, but the resulting joint would have been too bulky. There are other examples such some connectors such as those used on coax. However, I agree most electrical connections can be crimped or soldered. Whatever your preference, I think there is merit is discussing how to achieve a good low resistance and long lasting joint.
 
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Before/After soldering am a big fan of heat shrink tubing to keep things neat and tidy, helps prevent corrosion as well as supporting the join or connector you have just soldered, just slide a length up the cable before you solder or terminate a connector, heat with a cigarette lighter or heat gun to shrink it down for a tight fit. Also very useful for colour coding your wires and connectors if you use the same cable colour throughout.

Can come in handy for preventing cables from getting chafed in some areas too. I like to keep a stock of a meter or two in 3 or 4 diameters from 3mm up to 25mm, 2:1 or 3:1 shrink ratio is usually supplied from most electrical retailers and dirt cheap. Has innumerable uses for the hobbyist.

E2a: spelling
 
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