Originally Posted by Cheechako
"I would use Aluminum unless you have a bare unpainted mast. "
Pop rivets that is! I would probably still use aluminum
As noted above:Two holes at each pop rivet location. One dead center on the conduit location, and one to the side. Use a stiff bent wire like a coathanger on the side hole to pull the conduit up against the inner wall. Fill the extra hole with a pop rivet. Every 18" or even couple of feet should be adequate.
The annoying thing is a lot of thin wall extrusions are not a good marine
alloy unless in the states the alloys are different, second thing is when two alloys are side by side the less noble will corrode,, moisture cell etc etc pvc takes away a lot of that problem BUT in USA alloys may be matcheable....