GT mowog wrote:
Stainless fasteners can be very good - in the right application. I would express caution before using stainless fasteners. They will cause the adjacent steel to rust and have next to no tensile strength. They will also gawl when using a stainless bolt with a stainless nut and tightened. When this happens, it is almost like they are welded and usually need cutting apart.
This is exactly correct. Stainless in some applications is a gimmick and for car fasteners I would tend to think this is mostly the case.
GT Mowogs assertion regarding rust can be directly compared to having a sacrificial anode on a car or ship so that the anode rusts instead of the steel. In the case of a stainless fastener on an ordinary steel car, the car is the anode and you are effectively preventing the stainless from rusting by rusting the car. Not that the stainless would rust but the comparison is there.
In summary, stick with ordinary steel fasteners. They can be electroplated or painted etc but avoid stainless.
When we use dissimilar metals in big water mains etc there is usually an isolating component to the assembly. To prevent the corrosion in the car the isolation would be difficult, especially for self tappers etc..
