Aluminium pontoon tubes go chalky grey because aluminium oxidises on contact with air and water — it is the metal protecting itself, at the cost of looking terrible. The fix is a dedicated brightener, and it is the most dramatic before-and-after in all of pontoon cleaning.
What is happening to the metal
Bare aluminium forms an oxide layer within moments of exposure; in water, with minerals and waterline scum joining in, that layer builds into the dull grey-brown crust every untreated pontoon wears. It is cosmetic rather than structural — the oxide actually shields the metal — but cosmetic is the whole game on a boat.
Waterline staining adds a darker band on top of the general oxidation, same mechanism as any hull stripe.
How brightening works
Aluminium brighteners are acid-based products that dissolve the oxide layer and the staining bonded into it. Applied to a dry tube, allowed to work, rinsed thoroughly — the transformation is immediate and startling, from chalky grey back to bright metal.
It is also genuinely hazardous chemistry that etches whatever it touches too long, including the aluminium itself, painted surfaces and skin. Streak-free results take technique: work in sections, keep everything moving, rinse completely. This is the classic job where the product is cheap and the skill is the value.
Expectations and upkeep
Heavily pitted or decades-neglected tubes brighten dramatically but keep their pitting — chemistry removes oxide, not corrosion damage. A sealant afterwards slows the regreying, and an annual clean keeps tubes in the easy range.
Do it at end of season and the boat winters clean; do it in spring and it launches looking new.
Send a photo of the tubes as they sit — we will tell you what they will come back to and quote it done at the driveway. Read more about pontoon cleaning →