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flightlead404 · 21-01-2022, 08:43

Quote:

Originally Posted by thinwater

You would be incorrect about this. The reasons given in the development documents, based on experience, were:

Solder will soften if the wire over heats, and a solder-only join can pull apart.
Flex fatigue and wire breakage is more severe with solder only joins. I have seen this in testing and the field.
Corrosion is more severe on soldered joins. I've seen many soldered wires corrode off at one end, more than crimps. Properly located and sealed, neither fails.

Workmanship was not mentioned. Personally, I find soldering no more complicated than proper crimping (the crimper must be properly adjusted and the correct dies must be used).

I concur with all of those points. There is certainly a sharp strength gradient at the end of the soldered joint which will eventually cause work hardening then failure of the conductor strands if there is any flexing or vibration on the wire.

I personally prefer a quality PIDG crimp connection over a solder joint for this sort of thing. Use a quality crimp where the portion of the connector that crimps over the wire insulation is also copper. Use a good quality tool with the correct die and the mechanical and electrical connection will be at least as good if not better than a soldered joint.

BAD ORCA · 21-01-2022, 08:54

I think potting with epoxy would work IF the epoxy stuck well to the wire jacket plastic. It should though. Good heat shrink has epoxy lining and it sticks extremely well. It may be overkill but its not exactly time consuming or difficult to do.

If im REALLY worried about a particular connection staying sealed, I usually just use two or three layers of epoxy lined heat shrink on top of each other. each layer being longer and overlaping the previous layer.All of this on top of a heat shrink butt connector. This is how my current bilge pump leads are done.

I dont think it needs to be electronics potting epoxy either. Any epoxy that effectively cures fully at the applied volume used should do the trick. I think something as simple as West Systems or any equivalent any of us boaters have lying around would work perfectly well.

Bowdrie · 21-01-2022, 08:59

Per ABYC: "Solder shall not be used as a sole means of mechanical connection".
Good practice is a heat-shrink crimp connecter that is then covered by a length of heat-shrink tubing.
You do the best you can, call it good, move on to more important things, like up-keep on the varnish, LOL.

Bycrick · 21-01-2022, 09:34

Why would you think that epoxy would "stick well to the wire jacket?" Most "boat cable" has a PVC jacket, to which epoxy doesn’t adhere well without some kind of treatment. Did you remember to chemically clean any exposed metal?

Years ago, some of my company's engineers spent months trying to figure out what material to use to pot our equipment. Chemical compatibility? Expansion coefficients? The variations were seemingly endless.

Just pouring some random epoxy around some wire isn’t likely to do a lot of good.

Take a look at the various web sites from big makers of heat shrink tubing. You could spend days trying to optimize this. Shrink ratios from 2:1 to 6:1. Different wall thicknesses. "Engineered adhesives" for different substrates.

In most cases, just doing something only makes us feel better. Finding the "right answer" usually takes more time and research than people are willing to spend.

Cadence · 21-01-2022, 11:18

I think you are over thinking it. (pun Intended) As long as you can get the length of the pump mfg's wire to a terminal point above the bilge water level, voltage drop shouldn't be an issue, as long as you have sufficient wire gauge to that point. I would follow you line of thinking of potting at that connection in case of the pumps inability to maintain the water height.

Bycrick · 21-01-2022, 11:35

I can never find the "satire" font when I need it.

Boatyarddog · 21-01-2022, 18:10

Quote:

Originally Posted by RaymondR

solder the conductors together then slip heat shrink over the splice and shoot a good shot of hot melt glue into the heat shrink. The heat shrink will shrink and force the hot melt into any voids sealing the splice.

Or simply a waterproof connector that is applied with a heat gun.
Place high above the bilge water level.
Boatyarddog

boatpoker · 21-01-2022, 18:29

Quote:

Originally Posted by BAD ORCA

Good heat shrink has epoxy lining and it sticks extremely well. It may be overkill but its not exactly time consuming or difficult to do.

Please provide a link to "Good heat shrink" epoxy.

Boatyarddog · 21-01-2022, 18:40

Quote:

Originally Posted by boatpoker

Please provide a link to "Good heat shrink" epoxy.

Not epoxy, but excellent quality waterproof connectors.https://www.amazon.com/Connectors-Ev...a-633889686877
Boatyarddog

boatpoker · 21-01-2022, 18:45

Quote:

Originally Posted by Boatyarddog

Not epoxy, but excellent quality waterproof connectors.
Boatyarddog

I am familiar with that type of heat sensitive adhesive. I specifically asked for a link to the "epoxy" type as I've never heard of such an animal.

RaymondR · 21-01-2022, 18:51

I attempted to use the pre-adhesived crimp connectors on a deep well pump and they leaked so reverted to the solder/heat shrink/hot melt glue solution ever since.

For in-the-bilge wiring I now use the system illustrated in the images.

rslifkin · 22-01-2022, 08:07

Quote:

Originally Posted by RaymondR

I attempted to use the pre-adhesived crimp connectors on a deep well pump and they leaked so reverted to the solder/heat shrink/hot melt glue solution ever since.

For in-the-bilge wiring I now use the system illustrated in the images.

The heat shrink connectors are fussy about use of a good crimp tool and good technique. If either one isn't perfect, they can easily tear and then they're not watertight after shrinking. If in doubt, use plain metal (no covering) butt connectors and then slide on some heat shrink (adhesive lined and at least 3:1 shrink ratio) after crimping.