When the battery of my underwater, waterproof swimming timer goes dead, the timer emits a shrill, high pitched continuous alert. You figure this out because, as I mentioned, it is continuous. For hours, filling up the airwaves in any adjacent room or outdoor space. And you think it might be a signal for the end of the world that someone forgot to tell you about. And then you remember about that battery and validate that the sound is directly centered at the kitchen timer that is the heart of the underwater timer. Time to take action.
I had gone through the process of changing this batter once before, with a different waterproofing system. I had never had to undo the new, tightly screwed encasement around the timer, so I went to the engineer and asked for direction. It was his project and he likes to supervise my involvement. Besides which, I usually have a bunch of questions.
1. Taking apart the waterproof compartment:
The first thing I had to do was untie the waterproof compartment from the PVC pipe stand. The thick shoelaces were not to bad to untie, and were mostly left wrapped around the PVC.
The engineer grabbed a scrap of 2×4 lumber to prop up one side of the timer compartment. That way I could work on the timer without mashing it against the table top. The timer is a less sturdy plastic, mostly likely not made with any idea that someone would be using screwdrivers and hammers near it to change its intended safe kitchen function.
It turns out that a nut driver was the best tool to loosen the series of nuts around the plastic frame. The outside of the screws, nuts, and washers were starting to rust, but the portions of them that had been against or in the holes of the plastic were shiny. The engineer says that he will put aluminum screws, nuts, and washers on his shopping list, as these are rust proof. (click on any photo to enlarge)

Unscrewing the nuts and removing the washers was simple enough, but the screws themselves were harder. I began to patiently unscrew each one, dealing with screw heads that were a little soft from rust and recessed into the plastic, when the engineer said I should just pound them out with a hammer. Gently, of course. It quickly became apparent that this was a three arm job, so he got me a third arm from the scrap pile again. This second piece of lumber was placed parallel to the first and the edges of the plastic frame of the underwater timer were placed on them, with the middle of the timer slung in between. The screws had open air under them; I was not just pounding them into the wood.


The screws did not need to be hammered completely out of their holes, I was told after I had taken a couple of them all the way out. They just needed to be pushed far enough out that the two pieces of plastic forming the frame could be pried apart. With all of the screws having had this done to them, the plastic frame did, thankfully, come right apart.

The pieces of clear, soft plastic that the harder, white plastic frame was holding tightly together to form the waterproof compartment were not stuck together in any other way; so they, too, separated with ease. It was reassuring to see just how waterproof the compartment had been. There was not a drop or fog of moisture in there!

2. Getting the battery out and in:
Getting the AA battery out of the kitchen timer was complicated by the silicone that the engineer had filled all the crevices and screw holes with. This had been a measure just in case some moisture had gotten into the waterproof compartment. Some of the silicone was rubbed off with his rough, workshop fingers. Some was picked at with the tip of a screw driver and a paring knife. Just unscrewing the screws was not helping because we couldn’t tell which way to push the battery cover and it was being held in place. For the final step, careful prying with the paring knife removed the cover to the battery compartment.

There was some slight corrosion and leakage of the battery, for unclear reasons. Nothing looked wet in there either, but there was some residual of a gel that was in that space from the time we bought it, presumably to repel water from the batter.
A fresh battery was positioned and the cover reattached, but this time without adding more silicone. Hopefully this will make the next battery change easier! Before proceeding, we verified that the battery had made connection, and that I had set the option to minutes:seconds for the display. This is done with a tiny rubber button on the back of the timer, which has to be pushed pointedly in the middle. It does not respond to finger pushes once inside the waterproof plastic without risk of perforating the plastic.
3. Putting the timer back into the waterproof compartment:
All of the holes in the two pieces of hard plastic and the two pieces of soft plastic had to be aligned, because we didn’t want any extra holes! Fortunately, I had kept the soft plastic correctly positioned on its most adjacent hard plastic frame. I also had always kept the two hard plastic frames in the comparative position the ended up in when I took them apart. So, there was no puzzle.
It helped that the engineer showed me that putting the screws into one half of the plastic frame made it easier to see to line up the second half. Then, I used the hammer in reverse mode and tapped them all into place, with only the slightest jiggle to adjust the two frame halves. We were using the same screws, even though they were partly rusted, because they looked solid enough for now. I also placed the same washers over each protruding screw end.
After I had barely screwed a nut onto each screw end, I figured out how to hold the frame against my belly so that I could use the nut driver on one side and the screw driver on the other. The engineer suggested that it would be better to apply the turn to the nut via the nut driver, as it was harder to maintain good contact with the screwdriver end while turning. This worked well.

Another important detail was tightening the whole apparatus gradually and alternating the screws, so that it would go together as evenly and tightly as possible. It got harder and harder to keep track of which screw I needed to tighten next, but soon enough it was time to lay it across the scrap wood supports again and check them all one last time. The engineer nodded his approval of satisfactory completion.
4. Retying the whole thing to the stand:
This is where I discovered my only mistake. I had not positioned the timer in the waterproof compartment so that I could use the three holes drilled into the hard plastic frame for the shoelaces the best way. We both agreed that it was worth trying to go ahead with how things were.

It all looked fine until I went to pick up the stand with attached timer, and the timer unit swung to the side. We tried adding another shoelace to strengthen connections with the frame. This was better. Now, I just needed to know if it would stay stable enough in the moving current of my swimming pool.

The bottom line is that is was passable, but not optimum. The water current moved it just enough to make me concerned that it would end up whacking the PVC stand too hard one time and upset the timer. The engineer told me it will be no problem at all to drill another hole in the hard plastic frame. Then, I won’t have to worry about this alignment issue.
I had had my doubts that I would be able to tighten it all enough. It probably helps some that the clear plastic has some give to it that the hard plastic frame can sink into. Next time I need to change the battery, it should be easier, not only because I know the process, but because that silicone won’t be there. We will take that opportunity to replace the screws with the aluminum ones. I am happy to say that it was all waterproof again. I swam 20 minutes without stopping in the current and my underwater swimming timer worked wonderfully!
