Obelisk
I created my obelisk out of ¾" Down 'blue board' Styrofoam. The dimensions are roughly 18" wide at the base and 4' 6" tall.
Materials you will need:
Tools you will need:
Cut the sheet of Styrofoam in half to create 2 sections that are 4x4 feet. Then cut this in half to create 2 sections that are 2 x 4 feet.
Cut both 2x4 sections in half as shown below. The dimensions are not important. The angle of the cut determines the slope of the sides of your obelisk.
You will want to cut and discard the shaded portions shown in below. If you know enough geometry, you may be able to calculate the correct angles, but I just guessed. Ideally, you will want both long edges to be the same length, and the top and bottom should be perpendicular to a line drawn down the center. At the very least, you can experiment with one piece, and copy it's dimensions to the others.
Measure the width of the obelisk sides at two separate heights. Cut two squares of foam to match the widths. These will be used as internal supports. Find the center of the squares by drawing 2 lines from corner to corner, making an "X" across the square. Cut a hole the diameter of the PVC pipe in the center of both squares.
You will glue the sections together as show in below left. This figure shows the placement of the sections from the top. Glue three sides together, gluing the supports inside as shown below right. Cut the PVC pipe to size and insert into the internal support holes, fastening with glue. Then attach the final side. You may want to use small nails or tape to hold the foam together while it dries. (Yes, the obelisk is leaning! My guesses on the angles were not perfect)
Now it is time to start on the top. Set your compass to the width of the top of the obelisk (The ENTIRE width, including the extra thickness of the foam board on the side). On a spare section of foam, draw a straight line the width of the top of the obelisk. Then use your compass to draw arcs as shown in below. From the point where the lines intersect, draw straight lines down to the ends of your first line. This will make a triangle. Copy this triangle 4 times. These will form the top point of the obelisk.
You will need to trim the edges of the triangle at an angle, as shown in below. This will allow the triangles to be fitted together. Once again, you must estimate the angles. You can always cut out another piece if needed. Test fit the pieces together by fastening them with small brads or straight pins. When you have a good fit, glue the pieces together to form the point of the obelisk. It will be shaped like a 4-sided pyramid. Then glue it to the top of the obelisk.
After the glue dries, gently sand down all rough edges, and any edges where the foam may not match perfectly. Fill cracks with wood putty. Paint with gray latex paint, and finish with splattered black spray paint (See my Tombstones page for instructions on how to achieve a stone finish). I must admit that I used some special stone-finish paint, but wasn't quite pleased with the results.
The obelisk will stand on it's own, but you will want to slip the PVC pipe over a section of steel rebar to keep the wind from knocking it over. If you wish, you may insert a small screw into the side of the pipe, to hold it onto the rebar. Cut a small hole out of the side of the obelisk, at the bottom, for access to the screw. Fashion a handle out of wire to make removal of the panel easier, or simply use a pushpin as a handle.
As a final touch, I painted a Halloween door-knocker decoration, and glued it to the obelisk. You may decorate your obelisk with other objects. Happy Haunting!
Copyright
ã 1998