Water leak through potted wires


#1

I've finally done my first water test - and have a problem.

Water is entering the main tube coming in through the bundle of wires - so obviously I didn't pot this correctly during construction (I did have problems with the epoxy nozzle at this stage).

Does anyone have any tips or advice for making this waterproof now? It's going to be tricky to get new epoxy (or other more liquid glue) into all the places to properly seal the centre of the bundle of wires especially as the wires are rigidly held in the epoxy

I would rather not simply throw this section away and get new acrylic parts, and redo all the wiring!

Any advice would be much appreciated


#2

If the water is coming in between the outsides of the wires and the potting material (as opposed to between the insulation and the metal part of the wire), perhaps you could apply a vacuum to the inside of the chamber, put fresh epoxy on the outside of the potting, and let the vacuum suck the fresh epoxy in (the same way water would leak in), then once a bunch of epoxy has been sucked in, release the vacuum and let the epoxy cure. That may seal the path that the water would otherwise take. I haven't tried this, just thinking what I would do if I had that problem. Good luck, Rick

ps -- if the water is coming in through the wires, you just need to seal the outside ends of those wires.


#3

Thanks for your thoughts Rick.

As it happens, I am about to get back onto this in the weekend. I plan to get some marine epoxy resin that is very thin, possibly heat it if required, put it into a syringe (no needle) to inject the resin into any spaces I can get it into. I will apply the resin from the inside of the tube, then put the cover over and pressurise it. Add additional resin as required and try to get the resin to leak out the other end. It is much easier for me to pressurise the chamber than create a vacuum. I will trial the resin to see how fluid it is, and also how hard it sets prior to actually doing it!


#4

Did you use the recommended epoxy? That stuff seems very fluid, and it takes a long time to set up (ie, extra time to seep in). I purchased a hand vacuum pump with gauge from Amazon for about $25, and with that it is very easy to draw a vacuum inside the chamber. I would think you would hvae more success sucking the epoxy in than blowing it out.


#5

I'm in New Zealand, and couldn't get recommended epoxy. The epoxy I used seems OK. But I had major problems when I changed tubes after finishing the first one and tried to reuse the existing nozzle on the new glue - it simply wouldn't connect to the tubes. So I had to go out & get some more glue & nozzles - they are not sold separately. This caused enough delay to cause the problems.

Thanks for your advice regarding the vacuum - I will invstigate


#6

I had the same problem with the potting. I fixed the problem by applying epoxy to all of the spaces between the wires.