We’ve been making rocks for a week now, and finding a rhythm.
I work in Canberra all day, then drive home. Allison gets a kiss and a quick conversation, then I drop my dacks at the front door and put on my ever-more-fragrant concreting gear. Ally has her own work gear but she’s more modest.
We move the rocks from two days ago onto pallets, then Allison removes yesterday’s rocks from the moulds, cleans the moulds and paints them with face dye while I get the first concrete mix on.
We pour the mix into rectangular buckets – anything more than a third full is too heavy to manoeuvre – and then Ally pours them into the moulds while I get the second mix going.
After the second mix, I clean the mixer and we pack up. Currently it takes more than an hour, but that will come down as we become more efficient.
We then have to remember to go out in an hour or two to put some grooves in the back of the stones; that will help them attach to the wall later. It’s a quick and easy process with a gardening tool. Sometimes we remember just before bed, and it’s more like scratching grooves in.
The new (giant) mixer may allow us to do just one concrete mix a day, without the constant monitoring of the mixer, which will save more time.
We received some colour recipes from the US, but they use quaint imperial units like ounces and cubic cubits or something. They refer to colours of oxides that are different from ours. Australian cement bags are 44.1 pounds in the old measures. I set up a conversion spreadsheet for all the ingredients, and was very pleased when it turned out that two bags of Aussie cement gives us enough coloured concrete to exactly fill our moulds.
Our first couple of runs gave us rocks that were a bit washed out, with the cement colour predominant. We doubled the “sandstone” oxides and improved our application methods for the “marigold” face dye. That’s now our main mix, using some “light terracotta” oxides to give a bit of naturalish variation.