Where to get good corrosion resistant screws? (Not stainless)

[pvcces]

If a fastener is a different than the fastened material, you will have more corrosion problems. If they must be two different metals, then they should be near each other on the list of electronegative metals.

A good example of this happens when fastening aluminum sheets. If a mild steel fastener is used, it will corrode promptly when exposed to road salt, but stainless is near aluminum in the chart, so they work well together. Take a look at any outboard motor; most of the fasteners will be stainless.

Another metal you can check on is monel. This is often used in boats as a shaft material. I don't know if it could be used for fasteners.

Good luck.

Tom Caffrey