Originally Posted by
ranmar850
The best way I have found to keep even underwater joins perfectly waterproofed is to use non-glued type heatshrink, , at least 12mm in diameter. Do your soldered joins, heatshrink them with ordinary or glued, doesn't matter, but have a long sleeve of non-glued slid back up the cable, large enough to go over the finished joins. Slide it into place over the joins, then insert the fine end of a silastic nozzle into the tube and fill it up with silastic. Then start shrinking the tube from end, forcing the silastic along. As it comes out the other end, start shrinking from that end. This will force the silastic into every pocket, and seal the joint completely. I first used this when I was a commercial fisherman, and got sick of seeing boats full of water when the +ve wire would corrode off. I have used this for trailers with perfect results, works much better than glued heatshrink as it stays flexible.