I have designed some equipment that must be exposed to the UK weather for a year or two (typically miserable, cold and damp 99.9% of the time, then ridiculously blasting hot of the other 0.1%). I have concerns about galvanic corrosion between the brass, aluminium and stainless steel screws. I have sketched the design below. What are people's views about the longevity? I didn't realise the orange part would be brass when I had the alumuminium part made. Having dug around a bit I think it will be reasonably OK, but I'm tempted to have the aluminium parts re-made from brass if it shows signs of corrosion. Thoughts?