So I recently had a project suffer a huge setback. It started with me coming across some uniquely-shaped concrete pavers. I thought it would be an excellent project to start learning concrete with. I’ve been wanting to make concrete candles and planters but haven’t had a chance to yet. In hindsight, those would have been better choices to start with.
To make a custom shape paver, I first had to create the form that a mold would be made from. I wanted to make pavers in the shape of Ohio. To do this, I created a wooden version by stacking layers of plywood cut with a router. After researching, I decided to use Smooth-On’s products to create a mold that would be reusable for concrete casting. I needed to make the box that would be used to make the rubber mold. This is where I ran into problems. I didn’t see that the box had the slightest of gaps between one of the sides and the bottom piece.
The process to cure the rubber after it is poured takes a day when you’re being on the safe side. With the form in the center of my box I poured the rubber and everything went smoothly. However when I checked back an hour later, rubber was seeping out of one corner of the box. I panicked and wrapped a drop cloth as tightly and as close as I could around the edges. The damage was done already though. Too much of the rubber drained out and the minimum thickness of the mold became less than the 1/2-inch that is recommended.
Eventually I will take the frame off the mold and test it but in the meantime I’ve moved on to other projects. I will post a follow up when I attempt to use it with concrete.