What kind of rivets should I use to mount a steel mailbox door to an aluminum hinge?

Question

My mailbox was recently broken into with a pry bar. The door is steel but the hinge is aluminum (or other soft, non-magnetic metal).

To repair it, what kind of rivets would I use in this case: steel or aluminum?

The original rivets appear to be magnetic on one end but not the other. I have no way of sourcing the originals.

Alternatively, is there a higher security modification that I could easily make to this mailbox? This is for a rental and I don't want to spend a lot on a higher security mailbox. Any sort of nuts/bolts would need to be very short to fit inside the hinge when it's closed (folded over itself).

Answer 1

With Pop Rivets (blind rivets), you have a few choices:

• Stainless steel, such as shown in this example query on Amazon. Stainless steel is fairly strong, and does not rapidly corrode.
• Ordinary steel, which rusts, and leaves rust streaks on the box. It might be feasible to thoroughly clean around the rivets, and cover them with epoxy to delay corrosion.
• Aluminum, which is quite soft and easily pried out again, or just disintegrates over time. [However, the aluminum acts as a sacrificial galvanic anode, protecting the underlying box very slightly.]

However, as others have mentioned, I'd likely replace the rivets with inexpensive stainless steel security bolts (e.g., round-head stove bolt, Torx tamper-proof, or one-way slot), nuts and washers. If the bolt is too long, I'd cut it or grind it so it is just proud of the nut.

Answer 2

I would use Blind Rivets

Insert from one side, then use the crimp tool to fasten

The rivet it self is made from soft material (like Aluminum) to be able to compress.

How ever the mandrel (the inner part) is made from steal and will resist

Answer 3

Just be aware that binding steel to aluminium is asking for galvanic corrosion. Use plastic washers to try to avoid contact between the steel and aluminium parts, and keep the inside dry.

Aluminium alloys are less noble than steeel, so will corrode in preference to the entire steel box, so to limit corrosion of the fastners, steel bolts would work better, but isolation is best.

https://en.wikipedia.org/wiki/Galvanic_series

This does depend on your climate however - if it will always be dry then this is less of a problem

Answer 4

Replace the aluminium hinge with a steel one, and weld it to the frame and the door.

Makes for a harder job replacing it in 10 years when its worn out, but you're more likely to still have it.

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Separately, make your mail less-interesting by emptying deliveries from the box as soon as possible. Don't ever leave mail in it overnight, that's just baiting the bad guys to return.