Soldering??

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Spuddy

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I recall recommendations on here NOT to use solder for connecting wires. The reason given was that vibration would lead to fatigue fracture. I started off using crimp connectors when rewiring last boat but ran out so soldered the rest up. I've continued to use solder when tinkering with current boat as I'm not convinced. I wondered if it was one of those standards that have leaked across from aircraft requirements. Also engine vibrations only infrequent on sailing boats. Moreover all the electronic stuff is soldered up anyway including any off board wiring, I'm guessing.
So is there any real foundation for avoiding soldered joints or is it an old sea-wives tale that has just got handed down?
 
Good question! I don't know the answer but whether crimped or soldered there comes a point where the strands cease being flexible and independent and instead are now rigid, either soldered or crimped, and presumably the fatigue factor will occur either way?
Given the propensity for thin gauge wire to pull out of crimps my personal view is that a soldered joint is a better bet. 99% of the joints inside the boxes of electronics are soldered and they don't fall apart.
Im are someone can explain why I am wrong but like you I think this is one of those "in theory" things that's no bearing to the real world.
(having said that, I struggle on with crimps)
 
skyflyer said:
Good question! I don't know the answer but whether crimped or soldered there comes a point where the strands cease being flexible and independent and instead are now rigid, either soldered or crimped, and presumably the fatigue factor will occur either way?
Given the propensity for thin gauge wire to pull out of crimps my personal view is that a soldered joint is a better bet. 99% of the joints inside the boxes of electronics are soldered and they don't fall apart.
Im are someone can explain why I am wrong but like you I think this is one of those "in theory" things that's no bearing to the real world.
(having said that, I struggle on with crimps)
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As you say, crimp or solder the stranded (for flexibility) cable becomes a solid lump, at the boundary between solid lump and flexible strands you will get stress fractures. But only if there is no strain relief on the cable.. Crimped connections very often have this as part of the terminal construction/ tooling set up. Part of the crimp bears down on the insulation, first keeping all conductors well insulated, but also providing strain relief/prevents flexing at the electrical part of the joint.

Circuit boards:
Can be broken down into 2 categories of component. One has so many connections per mass that vibration is not an issue, integrated circuits in particular. Then there are the rest, which in high quality equipment have separate mechanisms for preventing stress due to vibration, whether that is being held against the board or a dab of glue, or even nut an bolt (power transistors, voltage regulators, TO3, TO220 package). again, in high quality equipment inter board wiring will have strain relief as part of its construction.
 
Spuddy said:
I recall recommendations on here NOT to use solder for connecting wires. The reason given was that vibration would lead to fatigue fracture. I started off using crimp connectors when rewiring last boat but ran out so soldered the rest up. I've continued to use solder when tinkering with current boat as I'm not convinced. I wondered if it was one of those standards that have leaked across from aircraft requirements. Also engine vibrations only infrequent on sailing boats. Moreover all the electronic stuff is soldered up anyway including any off board wiring, I'm guessing.
So is there any real foundation for avoiding soldered joints or is it an old sea-wives tale that has just got handed down?
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It's largely mis-quoted bollux.
AIUI, there is a standard that says a soldered joint should not be the sole support of a wire or cable.
Which is exactly right, all wires need to be mechanically supported to avoid fatigue at solder or crimp joints, by cable ties, looming, p clips, whatever.
There is plenty of soldering in avionics!
But, in avionics, they don't bother with lead free solder, so fatigue may be less of an issue.
You should not have problems with soldered joints, if you support the wiring properly with looming and cable ties etc.
If you don't, crimped wiring will be equally vulnerable.
 
The breaking of wires next to a solder joint occures when the wires are bent regularly resulting in metal fatigue. Providing the wires are well supported, all should be well. A couple of layers of shrink tubing can help to spread the load. Where possible clamp the wires near the solder joint so that it is not under stress.
 
I've seen such atrocious wiring on boats, the question of soldered or crimped hardly comes into it. I would always solder (a) because it's easy and reliable, and (b) because I can't be bothered to source the exact crimps for the job, or the correct crimping tool either. And I don't believe most who crimp even bother to try. The most important issues with solder is to get the right tools, and practice until perfect; nice shiny soldered joint, properly tinned, and soldered quickly and properly so the insulation doesn't have time to whither back. This question of joints failing due to vibration is a fallacy, but I expect a few contradictions.
 
elton said:
I've seen such atrocious wiring on boats, the question of soldered or crimped hardly comes into it. I would always solder (a) because it's easy and reliable, and (b) because I can't be bothered to source the exact crimps for the job, or the correct crimping tool either. And I don't believe most who crimp even bother to try. The most important issues with solder is to get the right tools, and practice until perfect; nice shiny soldered joint, properly tinned, and soldered quickly and properly so the insulation doesn't have time to whither back. This question of joints failing due to vibration is a fallacy, but I expect a few contradictions.
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That matches a lot of what I've seen.
Some amateur crimping is so bad they'd be better off with 'choc blocks'.
 
Flippin 'eck, that Nasa lot don't mess about - must take about a day to do one solder, but what a solder it'll be! I especially love the idea of a molten pot of solder at 260 degrees celsius being used in zero gravity - thats one floating blob to avoid.
 
sarabande said:
Especially the bit about removing oxides from the soldering tip.
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Yup, having the sponge damp is good, but coveralls are a useful standby also. Note though, that forgetting you're wearing shorts, and wiping the tip off on the missing leg of the coverall (skin) is something only done once!
Trust me on this!
 
jamie N said:
Yup, having the sponge damp is good, but coveralls are a useful standby also. Note though, that forgetting you're wearing shorts, and wiping the tip off on the missing leg of the coverall (skin) is something only done once!
Trust me on this!
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Yes, all that carbon based mess on the iron will have severe quality implications.
 
I'm ex aerospace electrical contact design engineer.

Some people (companies) demand crimp, some solder, both are equally vehement that theirs is the best.

Either way, a good connection is important, using decent tools and decent procedure.
 
guyd said:
I'm ex aerospace electrical contact design engineer.

Some people (companies) demand crimp, some solder, both are equally vehement that theirs is the best.

Either way, a good connection is important, using decent tools and decent procedure.
Click to expand...

In mass production and specialised repair, crimping might well be preferable. The process is cleaner, component specifications are known well in advance, and it's probably easier and cheaper to automate the process.
 
elton said:
In mass production and specialised repair, crimping might well be preferable. The process is cleaner, component specifications are known well in advance, and it's probably easier and cheaper to automate the process.
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Bloody sight quicker for hand assembly too. I used strip and crimp BNCs in around 45 seconds.

edit add

All that faff with a sponge is wuss, clean the iron with thumb and fore finger.
 
elton said:
In mass production and specialised repair, crimping might well be preferable. The process is cleaner, component specifications are known well in advance, and it's probably easier and cheaper to automate the process.
Click to expand...

Surely that's also an even stronger argument for using crimps for on-board work? On a typical yacht, you can cut, strip and crimp a terminal on under any conditions. Working away from shorepower requires a gas iron and they really do require a bit of practice! Working on a wire in situ rather than on a nice flat work surface is also much easier with a crimp tool rather than needing three hands to hold the workpiece, an iron and solder.

I've always believed that almost any method of joining wires can be successful if properly supported and incorporating strain relief.

Rob.
 
skyflyer said:
I don't know the answer but
Click to expand...

I really love forum replies like this & then follow with a whole paragraph of explanation- At least they declare ignorance first !!!! I suppose that is better than one having to deduce that for one's self


Sorry skyflyer please do not take offence I was not really meaning to pick on you in particular as your reply was sensible --but the opening bit just made me laugh
 
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I wish someone would come along and tell us how to make proper crimped joints.

Most of mine are enough to make an engineer weep.
 
When I rewired my boat this year and needed to join the loom wires to the cockpit instrument displays I too was puzzled what to use.
3M manufacture some very easy to use butt joint heat shrink connectors with a crimped terminal each end joined by a low melting point solder band.
Once crimped to hold the wires in place, the heat gun melts the solder and shrinks the outer cover for protection and additional mechanical support.
Unfortunataley, 3M's UK customer service couldn't say why this product is not marketed in the UK so I had to import a supply of various AWG sizes from the USA; I am pleased with them as they performed well and look just like any regular butt connector in size and shape
 
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