DIY rock recipes and suggestions

[Ptreef]

With it getting hard to find thin branched rocks I was thinking about a DIY rock (sand and cement). Any recommendations for recipes or experiences that would turn me off or on to this attempt? What did you mix in to make the rock porous if you tried? Results pics, existing threads?

 

[JohnK]

Wear gloves, cement will dissolve skin. Trust me, not pleasant.

DIY rock can be a fun and creative venture. It's well worth it if you have cheap sand (volume, room to make mistakes). Back in the day "southdown" was plentiful at $5 / 50lbs.

If you mix in dry pasta, it will dissolve in the curing process leaving voids and interesting textures.

If you want "branch" like rock, consider moulding it around PVC pipe or other reinforcement materials. Straight DIY rock can be brittle. If you do mould around PVC, consider leaving exposed ends so that you can join rocks together for aquascaping.

Plan to make 3-4 times as much rock as you expect to use. It's a learning process, curing takes forever compared to the fun and creative sand casting process. Sand casting...

Mould cement around dry sand to make caves and other void spaces.

 

[kgstei]

I made rock for my first salt tank 25 years ago. I still have some in my tank today. I used oyster shell and white cement. A friend shared this link with me and I think I'm going to give it a try on my upcoming build