Instant Shear Testing

When bolt is subjected to Salt fog test you can see in the image on the left that no rusting occurs, however when they are scuffed and the coating gets knocked off the water is able to get to the metal and start rusting. 

Here we again see that the bolt on the left shows the coating preformed well, however when mechanical damage/scuffing happens rusting occurs.

The black oxide coating whether scuffed or not, provides no defense to rusting.

No coating on bolts, whether scuffed or not, there is not rusting of bolt material during Salt Fog test.

What this means is that no coating manufacturer will guarantee that with mechanical damage their coatings will stay on. Runways can not avoid mechanical damage, therefore airports should look to use Stainless Steel bolts that are not impacted by rust or plan to replace many rusted bolts.

IES ALC 2017 Fall Technology Meeting

Dallas, TX  Monday afternoon 

(Final Presentation 10, 23, 17 Jeremy 2) pp. 55-58