These directions are for building a mold out of 3/4 inch wood.
The images included are for a cross that was used in an art installation, made using this casting technique.
Concrete is very inexpensive and a great way to make beautiful shapes for all sorts of projects without breaking the bank!
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Design Your Shape!
Draw out blueprints for the shape and size of the object you want to build. The mold here is a top till mold with a flat bottom, meaning the object will have a flat top and bottom after it is removed from the mold. Using small pieces of wood and nails, all geometric shapes can easily be assembled and combined!
IMPORTANT TIP: When assembling the mold remember to leave sufficient space to check that your concrete has filled the mold in the way that you want. For example you cannot build a perfect sphere using this technique because the mold must have a place to lay flat.
Step 2: Preparing and Pouring
Using masking tape, line all sections of the mold that may be susceptible to leakage. Concrete does not aggressively leak but is water-based so it is best to plan for the worst. Pour your concrete into the mold and smooth to the desired degree.
Step 3: Waiting and Breaking!
Wait the recommended amount of time for the cement to dry.
YOUR FORM WILL ONLY WORK IF THE CONCRETE DRIES WHILE IN THE FORM,
so be patient.
Once the piece is fully dried, simply remove the wood mold by breaking your mold. The concrete is much stronger than the wood, but if you are using a hammer, use caution!
Step 4: Presentation!
Objects made of concrete are extremely versatile and can be dressed up or down.
This one was displayed in an art exhibit submerged in sand.
These objects go great in gardens and are great decorations for any backyard or flowerbed!
Have fun making things out of concrete, these nontoxic creations are a fun way to customize the world around you!
Participated in the