Current mailbox post is coated steel, and, between the earth/air interface and the neighborhood dogs, severe corrosion is underway:
Yes, there is one 1/2” diameter hole all the way through the steel post at the earth/air interface.
Is there any technique that will save this mailbox post? Or, should I start fresh with a powder-coated cast aluminum mailbox post? Or, ???
If it’s already rotted right through at the bottom, it’s not worth saving.
Would Impressed Current Cathodic Protection mitigate the dog problem (don’t care: my dog’s a girl)?
A PVC heavy-wall 6" sewer pipe would do just as well and never have a corrosion problem.
Either a schedule 40, galvanized steel pipe (say, nominal 4" diameter) or lumber (perhaps, 4x4) treated for at least UC4A service (non-critical component in contact with ground) should look decent for 20+ years.
I think a zinc anode would likely solve this problem. You can get them (~$15) at a boat supply store or on the web.
Thanks for the ideas, folks!
I do have some restrictions though, by the dratted, all-powerful HOA. 
Even in that condition, the pole is likely a stouter structure than needed given the usual range of loads. Maybe the Mailbox Police could allow brick flower beds with a cavity to pour concrete around it?
Actually a black PVC sleeve at just above and below the ground interface. If you can find one with the right ID to match the OD of your post. Then again, below ground (a little) would also help, but that depends on what was used as a stabilizer around the post. If it was tamped earth, this would work. If it was cement, likely you need to replace the post.
The black PVC would closely match the post color, and provide what the electric industry uses as a pole reinforcement for ground line rot.
About 1 year later, we came back from vacation to find only about 1" of circumference metal was holding, so it was wobbly. To rectify this, I broke the post the rest of the way. It broke easily. I got a piece of 2" galvanized schedule 80 pipe, a bag of quikrete, and two SS long bolts with nuts and washers. I quikreted the 2" pipe inside the 4" existing mailbox post section in the ground, then put the existing 4" mailbox post with mailbox down over the 2" galvanized pipe and drilled and bolted the 4" post to the 2" pipe up top under the mailbox. Not as stable as original, but good enough!
We have a letterbox in the front door. The postman comes to the house and posts the mail through the door. No need for a mail box at all. Problem solved.
I thank you.
[from the UK where the postman comes right to your door as part of their Universal Service Obligation]
Excellent service!
Actually it takes an act of congress to move postal deliveries, in the US, from a mail box to the front door. I know this sounds stupid, but that is just how it works. I’ve had coworkers who tried that.
I have noticed that my schedule 40 PVC pipe will degrade and get brittle over time. I tried using a PVC pipe cutter and the pipe just fractured, so there are limits to what PVC can do.
My understanding is CPVC is better in services not protected from UV light.
You paint anything that’s going to be in the sun for a long time.
True dat.
