Port Hole Window Corrosion

Hey all,
I’ve got a couple of port hole windows in one of my staterooms that are made of aluminum that are routinely leaving white crusty material below the windows.
It appears to be corrosion. The windows don’t leak water. Seal is good.
This is Not happening to any of my other port hole windows.

Any thought on why this is happening and what to do to stop it?
I’m getting tired of cleaning up the white powdery mess.

Thank you!

Greetings,
Mr. T. I suspect your ports were originally anodized or painted. The coating has broken down for some reason. The white powder is aluminum oxide formed when water/water vapor comes in contact with the "raw" Al. NO idea why this should occur in only one stateroom but perhaps, "steamy" undertakings...enough said.

In any case, short of removing the offending ports and either replacing or re-coating, what you might try is cleaning them off really well with a good detergent agitated with a toothbrush followed by a wipe down with, say, acetone or denatured alcohol and giving them a couple of coats of clear sealer with a small brush. This is NOT a permanent fix but may minimize further "dusting" of oxides.

Rustoleum has a great water based primer for aluminum , a coat or 3 and in a few days it can be painted with oil or water paint.

Nicest looking is a rattle can of the color of choice.

The Rustoleum primer is the only primer I gave found that also sticks to galvanized .

2 great suggestions.
I will try that.
Thank you for your input����
Taras