This design is for a micro geocache container that is a fake rock made from cement.

You can paint or colour the rock to increase the disguise level. My example here I made a kind of red/pink colour.

The rock is shaped using the 2-part mould, the cache container is put in when the cement is still wet.

I used blender to make the rock. Blender file is included if anyone wants to change something.

The container and mould was designed using OpenSCAD. All files included. The threads.scad is not mine but is a library.

All printing was done with no supports. I printed the mould from PLA and the cache container and top from PETG. Layer height was 0.2mm for all parts.

It's possible to add text using the OpenSCAD file if you want to for example add the cache number etc. The stl's here have no text.

Instructions

1) 3D print the Mould stl file.
2) 3D print the Container and Top stl file.
3) Prepair the mould by applying wax to spoil the bond between the cement and mould. Failing to do this could make the cement stick to the mould.
I tried cling film(sarin wrap) and that also worked. I assembled the mould then pushed in the cling film.
4) Assemble the mould and use rubber bands to keep it together. Ensure the bands are not in the way of the hole in the mould
5) Screw the top and container together.
6) Mix a small amount of cement together with some colour die if required. You can gauge how much you need my putting the dry ingredients into the mould before mixing. For mine I used only a small amount of water until the mix just stated to bind. I did this so I could push cement in and make a hollow for the container.
7) Push the cache container into the mould. I kept the top on to prevent cement getting inside the container and also on the threads. It should be pushed in until the top is just above the cement. if your mix is dry like mine use a small stick to move the cement around to make space for the cache container.
8) Continue to push cement into the mould and around the cache container. I used a small stick to ram in the cement to ensure the mould was fully filled.
9) Scrape off excess cement from around the top that would stop the top from undoing.
10) Let it dry for at least 24hrs.
11) Demould and enjoy.

If anyone makes one I would very much like to see how they turn out.