This has been a project and a half , to make another vertical rock for an Ishitsuki i have planed for . The basic material is Hebel panel / Aerated concrete , 
Its light weight and is easy to carve , I have basically designed the rock and set about 
gluing it together with a construction adhesive and allowed to cure over a few days . 
With the panels secured together 
i have drawn the outlines of the design 
and then begin to cut away 
the access material using a sabre saw for quick removal 
to give the rock a basic starting point to work from 
. This is where the die grinder in in a league of its own , with a high speed steel cutter attached 
i begin carving the material out 
and basically shaping the rock 
With the basic shape carved , i have changed the cutter to a tungsten tipped carver 
and a rotary file for less effort 
and a cleaner more detailed finish
to its present form , being extremely careful of the reinforcement rods in the concrete panel material . 
It is time consuming and definitely worth the effort to create a unique piece custom made for the purpose and design in mind . After around 20 hours of carving and shaping its ready for the colour to be applied. 
I have chosen basic black as the highlight and applied it to the high spots to allowing the features carved into the panels to be outline to a greater depth 
. This is then brushed 
and rubbed over to blend the colour into a more natural looking texture .
With the colour finished off to the desired colour , 
it’s simply a matter of applying several waterproofing coats
and allowing it to dry . 
This will now be allowed to weather for a week the tested 
to see if it needs more waterproofing as the less agent used the more natural the finish is . I’m extremely happy with the result of this project , now all i have to do is decide which species of flora will grace the rock .
Cheers Alpineart