Fresh water spigot open or closed, a repair story

[bsbeedub]

The "Fresh water tank left open or closed" thread prompted me to start a new thread so as not to hijack the original. This is my story regarding leaving the spigot open or closed.
After un-winterizing at the beginning of the 2013 season my fresh water tank slowly started leaking. Since it was still attached to the trailer I could not tell for certain exactly where it was coming from. It was in the general area of the spigot though. It got much worse throughout the year and by the end of the season it was not a drip anymore but sometimes a full stream. It is only a 30 gallon tank and I had to fill it almost daily when camping. I removed the tank at the end of the 2013 season to inspect and attempt to repair it.
The original design called for the tank to have a hole drilled in it and the spigot assembly inserted in the hole and then plastic welded in place. The spigot assembly had pulled loose at the weld on one side which caused the leak and then it slowly got worse. ( I assume because of the weight of the water putting pressure on the already weakened assembly.) I can only guess that there must have been a small quantity of water left in the tank and with the spigot closed the water had no where to go and froze and cracked the weld. I did empty it at the end of the season so the amount must have been very little.

I have never even remotely attempted anything like this but I figured I should try it to avoid what surely would have been an expensive repair from a pro. I took my time since I had NO idea what I was doing (other than a YouTube video) and over the winter I was able to repair the weld with some polyethylene welding rods purchased from W.W. Grainger, a mini butane torch, and a soldering iron. It was leak free throughout the 2014 season.
It could have been frozen water or a bad weld from the factory. I'll never know for sure but I think I'll leave my spigot open from now on.