In a short answer - yes, but there's a catch.

Stainless and Aluminium are dissimilar metals, and with the presence of an electrolyte (like salt water) a battery is created which will corrode one of them. So it is ideal to keep the two metals separate, certainly in a salt water environment, bus is less of an issue in a dry environment.

What also comes into play is the surface area of each. For example, if Aluminium and Stainless are in contact with salt water, then the Aluminium (which is more Anodic of the two) will be the one to get eaten away. If there is a large area of Aluminium and a little Stainless screw there will not be much of a problem. However if you put a small Aluminium screw into a large sheet of Stainless then the Aluminium screw will quickly get eaten away. See more on Reducing the risk of Galvanic Corrosion.

So to keep the Aluminium/Stainless mix the rules are:

• Keep the Stainless part small and Aluminium part large (Stainless screws in to Aluminium NOT Aluminium screws into Stainless sheet.)
• Ideally, keep electrolytes like salt water away from where these metals are in contact.
• Separate the two metals in contact by using Tef-Gel to create a barrier between them (especially on boats and near salt water.)

So like I say - are Stainless screws in Aluminium OK? Yes... but follow the rules.

NB: This information is provided as a guide only and Anzor does not accept liability for the application of this information. For advice about Stainless Steel, contact the Australian Stainless Steel Development Association (ASSDA)

Rubber and Nylon Washers	Tef Gel	Galvanic Chart