All winter long we puzzling over a problem that has afflicted a series of small caches we placed last fall called the This Little Piggy series. We placed several of the caches in a camouflaged plastic spice bottles that we then suspended upside down from tree branches. We strung a wire through a small hole in the bottom of the container and sealed the hole with hot glue. To us,the seal looked airtight. Nevertheless,searchers repeatedly told us that the log books were soaking wet,and when we arrived to check them we found that they were absolutely right.
The puzzle was that we could find nothing wrong with the containers. The hot glue seal was sound and there were no holes in the bottle. Yet still the log books emerged soaking wet after the first good rain storm.
The last time we checked on of these misbehaved containers,we took a closer look and discovered what the problem was. Can you figure it out? Look at the photo (click to enlarge) and see if you can tell why the container was leaking even though the seals were sound.
Answer:The problem wasn’t in the seal but in the wire itself. If you look closely,you’ll see that the wire we chose is threaded picture-hanging wire. Even when the wire is wound tight,capillary action sucks rainwater down the threads and into the container. Even though the glue sealed the area around the wire,it couldn’t seal the tiny spaces in between the threads. We replaced hangers with single-strand wire and the problem went away.