We wanted a maintenance free and secure front fence, therefore - after some calculations - we decided on a concrete wall. It turned out quite ugly, so we planted several climbing plants on both side to let them cover it with the beauty of the Nature.
During the fence/wall building, it occured to me that we need a mail box, so we have just let one block out in eye-level. The original plan was to cover the front-face with 2cm thick concrete tile, cutting out a piece for the opening. While on the back side, I planned to cover it with a piece of plexiglas as a door. Then I went to buy a metallic cover for mail box opening, but it was so expensive tried wherever that I decided to do it by my own.
These are the steps I did until I get a satisfying result.
Step 1: Materials, Tools
At first I went to the local scrap yard and bought a piece of 3mm thick plate what used to be once a manhole cover or a door.
I also bought a "L" angle iron, 2cm*2cm. A 2m long piece was enough.
As material I used a pair of weldable metal hinges, four wire tensioners, some scrap bolts and nuts as well.
Total material cost was about 10 USD / 8 EUR
The tools I used are: welder (w.helmet, w.gloves, etc), angle grinder (with cutting and grinding discs, gloves, glasses), measure tape, drilling machine with some drilling bits.
As a hobbyist I have no workshop, even have no bench for such works, so I did it right on site, mostly on the ground. For better/nicer result I could enjoy such "luxury" as a workshop, workbench with a vise, a sawing machine, etc ...
Estimated energy cost was about 5 USD / 4 EUR
Worktime spent on was about 5 hours altogether.
Step 2: Back Side
The opening in the wall is 50 cm wide and 25 cm high.
I cut four pieces angle iron to form a frame. The end cuts were in angle. Then I welded them together.
First I wanted a transparent door (iron frame with glass or plexiglas), but I had no time to finish this at that time.
Step 3: Front Face
Without much hesitation I cut as big piece of plate as I could to cover well the opening in the wall.
Then I cut an opening in top-middle. This entry slot for mails is 25 cm wide and 5 cm high. It is a bit too high, but later was okay with the lid/door.
I cut and welded four piece 13 cm long angle iron. The wall is 15 cm thick, minus 2 cm for the frame - 13 cm.
Then I simply put the front plate and the frame in the hole and welded them together.
I wasn't satisfied with the result. It did not sit tightly in the wall. The entry slot was a bit big and there was no door on its back. On the other hand it was not ugly at all (at least for my expectations), and could call it a mailbox..
Step 4: Modification
I went to the hardware store and bought four wire tensioners. The barrel type with threads/bolts on both ends, but one of them is reverse (left hand). The barrel has a hole in the middle, by what the barrel can be turned and the bolts create tension. That is what I needed.
First of all I drilled some additional holes on the barrel to make me able to turn it in the corner. I also cut the end of the bolts.
Then I cut out the previous version from the wall by cutting the weldings at the frame. Then I cut shorter the "legs", and weld the reverse bolts in the corners.
Now the frame side: The bolts needed here some support, so I cut and welded a small triangular piece of iron in each corner. I welded the bolts to these.
It turned out that the bolts are too long, so it would take a thousand year to assemble the front and the back. (Or disassemble them in case of maintenance..) Therefore I cut them shorter, and left only 3 - 3 cm long bolts.
Step 5: Doors
There was left a piece from the plate what seem good size for back door. Found some metallic hinges at home as well. I like when things just "want to be put together by destiny"... :-)
From this cut the leftover was very good sized for a front door. Ahh doubled destiny.. :-D
I put them together with some cuttings and weldings and tadaaa, an (almost) weatherproof mailbox what I got.
Step 6: Finish
I simply assembled the pieces in the wall, tightly sitting help by the tensioners. This ad hoc weekend project finished.
I will take it out soon, and want to treat with anticorrosion fluid, then paint it. I want to put sealant where it contacts the wall to make it more weatherproof.