Making watertight Splice in Humid bilge area environment

[ramblinrod]

Originally Posted by mitiempo

If the crimp is a proper one the only addition after soldering is a hard spot at the end of the solder.

Here is a link to just about all you need to know about wire termination:

Marine Wire Termination Photo Gallery by Compass Marine How To at pbase.com

Any decent crimping device cold forms stranded wire to make a solid one piece conductor right at the crimp terminal barrel opening, very similar to what happens when solder flows around conductor strands right at the end of the solder flow.

A soldered connection done properly, is extremely strong.

(There are hundreds or thousands of solder connections in every marine electronic device such as MFDs, radar, and VHF radios.)

Done properly, during destructive pull tests, the cable breaks other than at the soldered splice (and requires much more force than to pull off a properly crimped connector using certified, calibrated tools).

It is true that a solid conductor is more likely to break when exposed to flexing or vibration than stranded.

This is why there must be secure cable clamps in close proximity to any wire termination, solder or crimp.

Another fallacy is that the solder creates dissimilar metal corrosion.

The greatest % metal in solder alloy is tin. Marine grade wire is tinned over it's entire length, every strand.

The reality is copper corrodes when exposed to air and heat, which is accelerated by presence of moisture, and especially salt water.

The primary causes of failed solder wire splices are:

1. Poor mechanical connection before soldering.

2. Cold solder joint.

3. Poor solder flow.

4. Over heating.

5. Conductors damaged with stripping tools (this applies to crimps too).

It takes a fair bit of skill and experience to get all of these elements right and quality control verification to prove it, which is why I recommend most DIYers use crimps only, made with ratcheting crimpers supplied by the crimp manufacturer.

I personally don't use prefab heat shrink connectors, but do use insulated crimp connectors, that I seal at both ends with RTV, and then cover with heat shrink tubing. (This reduces the number of connectors I have to carry in my service vehicle, and provides a more reliable seal, again when done correctly.)

[Lepke]

Never had a solder joint fail, can't say the same for crimp only joints. And I have an expensive ratcheting crimper.

[jimbunyard]

Originally Posted by Lepke

Never had a solder joint fail, can't say the same for crimp only joints. And I have an expensive ratcheting crimper.

Me, too. (though I've had some fail when I knew they were probably going to after I'd made them, such as when trying to solder 'black' copper wire [it is impossible to get all the 'black' off]).

And I've seen countless manufacturer-crimped connecters fail (if anyone should know how to do it, you'd think they would?!), most often from corrosion.

Quality crimped connections are pretty good, but for maximum longevity, crimped, soldered and adhesive-lined heat shrunk terminals are the way to go...as long has one takes the time to do it right.

[sailcrazy]

"NO. Twist wire nuts have no place on a boat. They are for a house or other static situation. Not mobile platforms."
OK, I know wire nuts are designed for solid wire, not stranded. But please explain your comment and where its written/said they are only for static situations? I've never heard that before, have never seen that before, and if the wire joint is NOT subject to movement I don't understand why a wire nut w/ silicon could not be used.....if you can get a tight, secure fit with it.

[waterman46]

Whether using butt crimp or terminal crimp, apply silicone seal and work it under and inside the insulation on the crimp connector. No real need for shrink tubing over that, and it may trap salt moisture. Yes keep them high as possible. Done this and its lasted more than 20 years. My next point is hard to explain. Mount pump and float switch on a stick. upper end of stick is secured to a point you can easily reach. To service the pump and float switch you dismount the upper end of this stick and use it to raise pump and switch assembly out of bilge with hose attached.

[N1EYO]

Harbor Freight has adhesive-lined heat shrink.
This is one of few items they have I believe in.

[ramblinrod]

Originally Posted by waterman46

Whether using butt crimp or terminal crimp, apply silicone seal and work it under and inside the insulation on the crimp connector. No real need for shrink tubing over that, and it may trap salt moisture. Yes keep them high as possible. Done this and its lasted more than 20 years. My next point is hard to explain. Mount pump and float switch on a stick. upper end of stick is secured to a point you can easily reach. To service the pump and float switch you dismount the upper end of this stick and use it to raise pump and switch assembly out of bilge with hose attached.

The "Christmas tree" bilge pump stick is a common solution for vessels with very deep, narrow, and hard to reach bilges.

On our Douglas 32, the bilge is well over 3 feet deep, and only 6" wide at the bottom at the widest point.

The only way to get bilge pumps, float switches, and a waterproof junction box down there is on a bilge pump stick.

[newhaul]

Originally Posted by sailcrazy

"NO. Twist wire nuts have no place on a boat. They are for a house or other static situation. Not mobile platforms."
OK, I know wire nuts are designed for solid wire, not stranded. But please explain your comment and where its written/said they are only for static situations? I've never heard that before, have never seen that before, and if the wire joint is NOT subject to movement I don't understand why a wire nut w/ silicon could not be used.....if you can get a tight, secure fit with it.

OK well let's see anything and everything on a boat is subject to movement and vibrations. https://www.westmarine.com/WestAdvis...nal-Tech-Specs

Follow the ABYC Standard in Electrical Wiring and Connections | SailAngle.com

Wire nuts (cone shaped devices with a spiral wire or plastic threads inside) that most of us are familiar with in our home lighting are specifically banned by the ABYC. Wire nuts are not designed to be used on stranded wire. Even in residential use, one of the wires must be a solid (non-stranded) wire. To tighten correctly, the wire nut will cut fine grooves or threads into the solid wire. When both wires are stranded as on a boat, the wire nut won't tighten adequately and worse yet, may actually cut or break the fine wires in the strands. Because they can't cut threads into the wire, wire nuts are subject to loosening with vibration. Finally, they are difficult to seal against water and corrosives. It makes sense that they are banned by ABYC.


Hope this answers your questions.

[Cheechako]

Use the connectors with the good heavy shrink wrap right on them. The good ones ooze goo when you heat them as well as shrink tight. The other thing I've done with bilge pumps is put a connector strip on the floor support and just use that, but those will corrode eventually, if you cont coat them.

[ramblinrod]

Originally Posted by waterman46

Whether using butt crimp or terminal crimp, apply silicone seal and work it under and inside the insulation on the crimp connector. No real need for shrink tubing over that, and it may trap salt moisture. Yes keep them high as possible. Done this and its lasted more than 20 years. My next point is hard to explain. Mount pump and float switch on a stick. upper end of stick is secured to a point you can easily reach. To service the pump and float switch you dismount the upper end of this stick and use it to raise pump and switch assembly out of bilge with hose attached.

Differing opinion (which is what makes forums so entertaining).

I feel that heat shrink tubing over silicone sealant is absolutely essential to high reliability in a crimped connection.

Silicone sealant is relatively fragile and can easily be ripped or abraded exposing bare conductor.

Applying heat shrink tubing over it, compresses the uncured silicone sealant, forcing it into cavities for more assured sealing.

(Liquid electrical tape can be used, but is highly flammable during curing.)

The tubing also provides a protective sheath around the relatively fragile silicone sealant after it cures, and acts as a strain relief at the crimp connector join, which as just mentioned in previous post, becomes a cold formed single conductor at the conductor/connector join, which is much more prone to damage due to flexing and vibration.

I have tested too many prefab shrink terminal connectors that have failed to seal to rely on them, especially if the joint is flexed significantly, shortly after shrinking, like when tidying up wiring on job completion.

[Colin A]

Originally Posted by mitiempo

If the crimp is a proper one the only addition after soldering is a hard spot at the end of the solder.

Here is a link to just about all you need to know about wire termination:

Marine Wire Termination Photo Gallery by Compass Marine How To at pbase.com

My self I generally just crimp. But I know people who do both. There used to be a fishing boat builder that did it (can't remember which one) but they would solder the end of each ring terminal after a crimp. Since it was at the terminal end not the entry end I can't really see it causing an issue and most likely helped a little.

There are also the terminals that have a little solder in them when you heat the shrink tube it also flows a little solder on.

[Colin A]

Originally Posted by Lepke

Never had a solder joint fail, can't say the same for crimp only joints. And I have an expensive ratcheting crimper.

I have seen plenty of both fail all comes down to the guy doing it.

[mitiempo]

Originally Posted by ramblinrod

Any decent crimping device cold forms stranded wire to make a solid one piece conductor right at the crimp terminal barrel opening......

Agreed. Therefore what gain is there to soldering this connection? Solder will not flow into the crimped portion.

[skipmac]

Originally Posted by mitiempo

Agreed. Therefore what gain is there to soldering this connection? Solder will not flow into the crimped portion.

And, a proper heat shrink butt connector will also be totally waterproof so soldering really adds nothing except more work and a hard spot that is a potential failure point.

[skipmac]

Originally Posted by Colin A

I have seen plenty of both fail all comes down to the guy doing it.

The person doing it and the tools and parts he/she uses. Using the correct, ratcheting crimper and the correct, matching crimp connectors it is almost idiot-proof.

But you know what they say, it's impossible to make anything 100% idiot-proof because the idiots are so ingenious.