Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
I've used a product called 'Zinga' before. I coat all crevices and exposed threads with it. Its a brush on zinc type coating used by electricians to protect the cut ends of galvanised conduits to stop them rusting. I'm not sure if you can still buy it but try an electrical retailer like Wholesale Fittings, or RS Components they may stock it. I work on the underground and I've never seen conduit corrode when this product is used. The tube can be a harsh environment with damp and humid conditions.
Best spray some car body underseal on afterwards.
I like waxoyle.... it’s messy but once applied gives great long lasting protection, doesn’t chip off like paint...