llbaker2 said:
Electrical tape ... it works, as all it does is INSULATE the stainless steel fastener from the tin.
If you have sacrificial anodes mounted in various spots is galvanic corrosion still an issue?
Yes, as metal-to-metal actions between dissimilar metals is galvanic corrosion. Those anodes you're talking about prevent electrolysis.
Electrolysis is the forced introduction of an electrical current in an electrolyte (water, or even worse ... SALTwater) that causes a chemical reaction that separate the components of metals into the water, where the less noble metal gets eaten away.
Galvanic Corrosion is a form of electrolysis, in that it too is an electrochemical reaction that causes electrons to flow from the less noble metal to the higher noble metal, but occurs locally at the site where the 2 metals touch each other. See the chart? The farther away the 2 metals are on the chart, the more the corrosion can occur.
It ain't rocket science, heck when I first learned of this topic I just added duct tape under the heads of SS washers. Took a boat apart (used in saltwater) many years later and all was fine. Nowadays I've just 'refined' my build techniques and use the little bit more elegant solutions of nylon washers and heatshrink. Regardless of the material used - insulating different metals from each other works!
Shear Strength
While we're back on this topic last night ... I looked it up in my engineering books and SS through bolts in 10-32 or 1/4" sizes offer shear and tensile strengths > 6X times that of comparable sized rivnuts, and pull out strength far, far greater, as an FYI.