Cleaning toons. Am I doing it wrong?

[gobeernet]

'99 Bennington. Previous owner stored it on the lake. Had decent water lines on both toons. I wanted to get the water lines off if possible. I'm not concerned with a mirror image, but am shooting for a consistent medium gray. Such as a brushed aluminum.

First attempt was aluminex "aluminum brightener" then pressure washer. Everything below the water line did what i was hoping. Everything above the water line turned white. Picture below.

I stopped for a bit and did some reading. Found a few bass boat guys saying 120 grit on an random orbital palm sander leaves a consistent finish. I picked up a sander and 120, 180 and 240 grit. The finish is fine by me, but how do I get it consistent? I can see the path of the sander.

Pictures show most of what I'm talking about. Pictures uploaded in reverse order so bottom to top is order of operations.

Any suggestions?

[grouser]

I feel for ya man,,, that's allot of work to not be happy with the results. I think yo need to be consistent with the final pass. What ever you do as a last prep must be on the entire toon IMHO. I am going to go with a power grinder with a buffing wheel and white and rouge compound just like I do with my Harley parts,,, good luck !!!

[Mrtoler]

Get them all sanded smooth and looking like you want... Then acid wash them and it should look even!

[gobeernet]

Get them all sanded smooth and looking like you want... Then acid wash them and it should look even!

Acid wash with the Aluinex I have or something different? Hydrochloric acid is the highest ingredient in the Aluminex.

[HandymanHerb]

Just keep going up on the grit till you get to 4000 and you should be even, then protect it with shark hide

[Mrtoler]

I use either sharkhide cleaner or an AC coil cleaner to acid wash the tubes.