This instructable only contains a few images of it construction as I did not document it during the build but I will guide you guys and girls through it. It is a typical British post box but the design can be changed to suit and style of post box.
The first step is to decide what sort of size you would like the post box. The two that I have made so far have been approximately 2 and half feet tall. Then some MDF ring need to be cut out. I used a router to do this so they we dead round. I had 1 solid for the base, 2 internal ring to hold the shape from the inside, 1 external ring to act at a collar and 1 final circle to be the piece for the lid.
I then used card to make the body of the letter box this was done using 2-3 layers to add strength and help keep the round shape to the post box.. I used the rings to keep the shape and used super glue and hot glue to fix everything together. Once I had done this I then marked out the opening for the letter box and cut out with a shape craft knife. I then built the mouth of the post box around the hole that I had just cut.
The lid was made by adding cardboard to the top of the ring and then using body filler I made the top smooth. It took a few passes of filler and sanding to get the shape and finish that I was after. To make the lid sit on the top of the post box I made another ring of card also 2-3 layers thick to help hold the shape of the post box. But this ring of cardboard was slightly wider than the main boy so that the lid would just slide of the top until it reached the MDF collar that I added. This card ring was also fixed to the top by used hot glue.
You can also ad a little place for a sign to go stating the pick up time for the post and location etc. This again was made from card.
Once all of this is completed then its time to fill any hole or cracks that you might have. Then it time to paint the post box. I applied 2 good coats of grey primer allowing drying time between coats. The I masked off the bottom section and sprayed the top red. This also had 2-3 coats of paint, also allowing drying between coats. Then mask of the top section (Red section) and apply the black paint to act as the base section. This also has 2-3 coats. Once all the paint is dry then apply 2-3 coats of clear lacquer to finish off.