In the previous post, I described the beginning of my big sand wall project. Today, we will look closer at how I made my own lids for the boxes and how I prepared the wall for sand.

Previously, I ended up ordering more square moulds. They finally arrived, and I started pouring a few boxes from resin, but the whole process was pointless until I found out how to keep the sand in the box without a lid. I thought about pouring sand into the resin, but when I tried it, the sand lost its colour and structure, and the whole box was very heavy. This was not the way.

Somehow, I had to modify the lid for the box. Coincidentally, I listened to a fellow coder and enthusiastic beekeeper who makes candles out of wax and who had created moulds from silicone rubber only about a year before. I thought I could try a similar method. I bought a few kilos of silicone rubber and was thinking about how to model such a lid. A few weeks later, I suddenly realised how I could "fill up" the box with resin and put it back in the rubber upside down so that I could get the shape of a lid. Otherwise, it was not possible; the front side has a "border" (for future labels, remember?) and could not be used for the shape of the lid.

Creating a silicone mould was an experience. Once I managed to spill a dose of silicone around the office; it was a pure apocalypse. I used a sewing cutting board, bordered it with basic rulers, and taped the sides of the rules and the board. That was enough to keep the silicone rubber from leaking. Silicone rubber is a much bigger buddy than resin. Resin gets through anything; it gets anywhere.

I don't have a photo of the process, but I carried it out by first pouring a layer less than a centimetre thick over a large area. I let it harden (one day is enough) and put the filled resin boxes on the hardened surface. I loaded the resin boxes with something heavy to keep them from moving and poured about 2 to 3 cm of the silicone rubber between them. I waited a day again, then cut it into moulds. I had about eight lid moulds at once.

Time passed and suddenly it was the summer of 2020. The borders opened again and I ran as soon as possible. When I returned at the end of October, and the borders closed again, it was time to finish the project. I had boxes and a mould for the lid, but that wasn't all I needed. What about my idea of putting the boxes on the wall?

I had to figure out how to "use" the magnets. Who knew magnets were so expensive? I bought a few magnets from China, but they took a long time to arrive, and they were pretty weak. So, I purchased magnets from the Czech e-commerce store UNIMAGNET with the dimensions of 42 x 20 x 3 mm; I wanted to put the magnet into the lid. I calculated that the box could weigh up to 300 grams with the sand and the lid, so I needed a stronger magnet.

Another question was how to hold the magnet in the lid. I decided the most straightforward solution would be the best in this scenario; just putting it into the lid. Ultimately, it turned out that the best way to proceed was to pour about 2-3 mm of the resin into the lid mould, wait a day for it to harden a bit, then place the magnet on the lid and pour the rest of the resin. The magnet thus holds itself in the lid.

I could have already felt like I was near the end, but a few crucial things were missing. Maybe where to put the boxes, right? The original idea was a metal wall, but metal is heavy; who would have thought that? :) Whatever the final result would be, it would require a lot of drilling into the concrete wall. Therefore, I decided to involve my father, who is great at home improvement. This was a critical moment because, until that point, I had told hardly anyone about this wall. The fact that it wasn't done yet was just my problem, and no one could have asked me about it. However, telling my father about the idea meant I would have to finish this project at all costs.

My father liked the idea; we started thinking about how to do it more efficiently. The large metal area turned out to be very impractical, so I came up with the idea of long narrow metal plates that we would drill on the wall; each plate would be one row of boxes. The idea was good, but basically, the whole wall would have to be drilled through. One plate needed three to four holes, and I wanted at least 12 rows. That's about 50 drilling holes in the wall, where (by the way) there are electricity cables.

My father came up with the idea of a large wooden desk that we could drill on the wall with just 12 drilling holes and then drill the metal plates on it. But where to get such a desk?

We create stuff a lot, the whole family, so it's probably no surprise that we have something like a family carpenter in Strakonice town. My father made a deal with him, and he got us a big wooden desk for a small amount of money. The rest of the desk will be used for another DIY idea, which I will write an article about as well. The carpenter did not ask why; he probably protected his mental health and cut the board as I told him, and it was done.

I bought steel plates in an e-commerce store for a few hundred CZK; my father painted them in his garage and pre-drilled four holes in each plate. In the meantime, my father brought the wooden desk to Prague. He comes from Strakonice, so he used the trip to check on his mother, who still lives in the Strakonice town where he is from. He owns a car with a large trunk so he could transport the desk, which was 140 x 120 cm.

The desk arrived in the apartment; I had metal plates, nuts, and wall plugs ready. The only thing I underestimated was the weight of the wooden desk. I couldn't pick it up while drilling it, so my father came to the rescue, and we drilled the desk together. First, I marked where exactly the plates would be on the board; then we drilled the wooden board on the wall. When it was on the wall, we drilled the plates on it. By the way, it ended up being 13 rows.

In the next and last post about the sand wall, we will make it to the very end. I'll show you how it all turned out and whether it was worth it :)