[Thomas Sanladerer] wanted to create some molds using 3D printing for concrete and plaster. He used a delta printer with flexible filament and documented his process in the video below.
If you’ve printed with flexible filaments before, you know you need an extruder that has a contained path. [Tom] borrowed a printer, but it didn’t have that kind of set up. The first step was to swap extruders with another printer.
Some scrap wood made a box for the positive model. [Tom] used a concrete-based mortar since he didn’t have real concrete ready for this test piece. However, his ultimate goal was to use concrete which he did when creating a final piece — an on-air sign — that he documented in several other videos.
The first attempt had some cracking and it looks like he may be pulled the mold too early. A second try with plaster gave much better results. [Tom] then experimented with painting the plaster to get a different look. In a follow-up video, he addresses some of the comments he got on the previous videos.
We often forget that concrete is easy to use and creates things of good substance. Of course, instead of casting it, you can print it directly with the right gear.
Source:: Hackaday