Speaking of Chinese fillings,.....
Years ago I had a bad valve on the feed line to a water heater. I was working midnights and didn't have a lot of free time. I decided it would be a better course of action to simply replace the entire valve than to try and fix the one I had. I picked up a replacement valve one morning on the way home and swapped the valves out the following evening before I went back to work.
Turned the water back on and the new valve had a pin hole in the casting. A tiny jet of water was shooting out of the valve body. Must have been an inclusion in the casting. You couldn't see the hole but it was there.
I was less than amused.