<a href=showthread.php?s=&postid=11312057#post11312057 target=_blank>Originally posted</a> by Worldwithin
you could create a splice via soldering them together. Once the splice cools, you can gob silicone over it, and then slide the heatshrink over the gob of silicone, effectively creating a sealed splice. Shrink the tubing while the silicone is still gooey and then once the silicone dries, it should be completely sealed. For added safety, you can silicone the ends of the tubing shut as well. The object is to seal the splice as best as possible with the silicone, trying to not get any air under the silicone. Then compress it with the tubing.
I have done this a few times in wet locations with great success. There is always a chance of failure, but if you need to splice in an area that will need to be wet, this is a rather non-toxic option.
:fish1::hammer: