Easter is coming soon and I hope that alot of you will find this instructable helpful. I'm going to show you how to make giant Easter eggs out of regular insulation polystyrene. I used 100 milimeters thickness polystyrene for making 1 meter eggs. You can use this tehnique for making almost any round shaped object.
Step 1: Draw the egg
First of all you should know how to correctly draw an egg. I'm usually using circles to draw the eggs, just like in the picture. At this point you also need to choose the polystyrene thickness and use it on your scale drawing. This way you'll be able to find the diameters of the circles you'll be cutting later out of insulation polystyrene. Don't worry, you'll see in a minute exactly what I'm talking about.
Step 2: Cutting the circles
I used a jig saw for cutting the circles. I found a special long blade designed for cutting polystyrene. I actually cut some of the smaller circles out of the bigger ones, so my egg was almost empty on the inside and also very light. After cutting the polystyrene circles you must glue them together in the right order. I used regular insulation polyurethane foam as a glue because it's light, has a great bond, and also because it was the best choice, considering the following steps.
Step 3: Preparing the "lathe"
The idea is to cut out the corners of the rough egg and make it smooth and round using your drill "lathe". The lathe is actually made of a long screw that goes through the rough egg and two polywood circles. The whole lathe is powered by a driller.
Step 4: Using the "lathe"
Here's a video with the whole procedure, and also a picture of some eggs we made. You can paint them after with any solvent-free paint.