While paging through the feed a few days ago our attention was caught by something a little away from the ordinary in Hackaday terms, a DIY video about creating cast concrete signage from [Proper DIY] which we’ve placed below the break. A deceptively easy-looking mould-making process has a few tricks that will make the difference between a hard-wearing sign that lasts for years, and a lump of concrete.
So, to make a cast concrete sign, you throw together a mould with some letters, and chuck in some concrete? Not so fast, because the key appears to be preparation, and ensuring that there are no 90-degree corners on the mould parts. The letters are carefully shaped and sealed with varnish before being attached to the mould with silicone adhesive, and all the corners are beveled. Finally a light oil is used as a release agent, and hefty vibration takes care of any air bubbles.
The result is a set of signs, but we can see these techniques finding uses outside signage. For example, how about casting using a 3D printed mould?