Carpentry and plumbing
What is Carpentry?
The art of cutting, framing, and joining timber, as in the construction of buildings. An assemblage of pieces of timber connected by being framed together, as the pieces of a roof, floor, etc.; work done by a carpenter.
What is Plumbing?
The pipes, fixtures, and other apparatus of a water, gas, or sewage system in a building. The work or trade of a plumber. Informal. An arrangement of bodily vessels or ducts: "treating stroke victims by reversing the plumbing of the body's circulatory system" (Associated Press).
How to make Hallow Blocks
Inflate a beach ball and use a felt pen to draw a circle around the top, with the air valve in the center. This will be the opening of your concrete block.
Apply water-based concrete-releasing agents to the entire surface of the ball.
Wrap strips of hardware cloth around the surface of the ball, leaving the area inside the drawn circle clear. Be sure the strips remain as evenly spaced as possible: Multiple layers on top of one another will create an uneven surface, which makes it trickier to get the concrete sphere right.
Place a layer of wet concrete around the surface of the ball. The layer should be a uniform 1/2 inch thick around the entire surface. The area inside the drawn circle should be kept completely free of concrete mix.
Allow the concrete to harden for at least 24 hours.
Deflate the ball and carefully remove it from the concrete.
Add additional layers of concrete over the first until the block is of the desired thickness. You may wish to do this in stages, adding a little concrete at a time instead of placing it all on at once.