HELP - Water proof wire connection

[Frank S]

I would think the first step will be to kill the corrosion. Not as easily done as some may think. I have had god success using a product made by KBS coatings but others are available the Rust Blast when used as directed will kill and remove corrosion but should be neutralized afterwards on copper electrical and aluminum and brass.
But this would be true for moat any corrosion dissolving solvent.
Then what I have done in marine applications before making connections I would slide lengths of shrink tubing on each individual wire then slide a larger piece of shrink tubing with dielectric coating on the inside over all of the wires tightly twist the clean bare ends of the wires together and fold that back on itself when possible then use an electrical solder paint the connection with more dielectric grease as I call it . slide all of the shrink tubes up as far as possible and slide the larger covering tube over all of these then heat the large shrink tube will bond with the smaller ones the smaller ones will bond with the wires and the insulation. the reason for the small individual tubes is they will form a bond between each other removing any possibility of exposure to air or moisture between the wires where as the single large cover tube can not do this by itself when 2 or more wires are entering from 1 end. On Aa running splice connection with only 2 wires a single cover tube can make a sealed bond.
There is another simpler way to make a lasting seal which is by using the dip-it liquid rubber type product you see advertised for making non slip grip handles on hand tools. This only works for end type connections not running splice. you dip the connection into the rubber allow it to cure then dip it a second time and a third if you feel it is required. once fully cured it will be a durable air and moisture tight covering.
Hope some of this helps