It’s Not Invisibility

Beautiful, isn’t it? What is it? It’s the joint between two sections of a fire-escape handrail in Brooklyn. Each section has a frame around its perimeter made up of small wrought-iron angles, which are bolted to the balcony framing below and to each other at these seams. So the angle on the left is part of one section of handrail and the angle on the right is part of another.

Just about halfway up the left side you can see a small bolt shaft and nut, drowned in paint, where the two sections were connected. There’s just one problem: you can see air in the seam between the two angles where the bolt shaft should continue to the right. Here’s where the line of the shaft would be:

Oops. There’s no intentional deception here. Rather, there was a small bolt with its head on the right and the nut on the left. Small pieces rust faster than big ones because of that pesky surface-area-to-volume ratio, and in this case some rusting of the vertical angles may have also created a jacking force that put the bolt in tension, which would exacerbate any issues arising from rust reducing the bolt diameter. In other words, it rusted until the shaft broke and the head end popped off.

Probably someone should have noticed when repainting, but (a) it hasn’t been painted in a long, long time and (b) I’m not going to hold a painter responsible for any safety issues other than his or her own.

The moral of the story: a new bolt will be installed shortly.