I live in California. Nobody even knows what ytong is, let alone has it for sale. Pumice was another highly rated nest material, but finding it in pieces larger than sold for cleaning was impossible. The next highly rated material was tile grout. I cast two nests out of that. I carved them before it set completely. They were heavy like bricks and I couldn't modify them once they dried.
I had an idea! It worked out better than I ever expected. I am going to share my revolutionary recipe with you.
You will need perlite and tile grout and plastic wrap to line your mold, wood to form the sides, coarse sand to add texture, and modeling clay to hold the wood in place. I used what is called saltillo grout because it was the cheapest. Saltillo grout is sanded grout made to spread under floor tile grout. It can handle joints larger than standard sanded tile grout.
OK, mix the perlite and grout approximately 50:50. Do not use more than that in perlite. If you aren't sure, use a bit less. Add water, mix well. The perlite will absorb lots of water. I used my small aquarium as a mold. I placed 1'' x 2'' x 6'' wood on the two sides and a longer one for the top. I lined that with plastic wrap, being careful to not have wrinkles. I poured the perlite grout mix into the mold. I used playdough, modeling clay to hold the top wood piece in place. For texture, I patted coarse sand onto the top surface.
Let the slab set overnight. Remove the wood and carefully pry up the slab. You can carve it easily with a dremel tool at this time, or you can wait until it is convenient for you. I use grinding stones, tile cutting bits and grout removing bits to carve out my tunnels and chambers.
This is a link to pictures and instructions: Hyperlinks sind nur für registrierte Nutzer sichtbar
this is a link to more pictures and yes, I do have duplicates since they are in different sites: https://picasaweb.google.com/1157954974 ... RMICARIUM#