HELP with dirty aluminium!

[jman72637]

I have a 19' Alaska Grayling. It is a heavy duty aluminum boat and has seen much of its life in saltwater(previous owner). This thing is scared, oxidized, stained..... everything you can think of. I can take Miguires aluminium polish and rub the same spot 15 times and it still turns the rag black! really black! I spent 40min. on a spot about a foot long and I could still be there to this day. I am just curious if any of you guys know any secrets to making this process any easier....or if it is just good old plain elbow grease that is going to make my boat pretty again. Thanks is advance!
J

 

[tashasdaddy]

Re: HELP with dirty aluminium!

try a good strong, pressure washer, wash down with dishwasher soap, it works wonder. then pressure wash.

 

[gcboat]

Re: HELP with dirty aluminium!

Cream of tarter or white vinegar in a solution will take the surficants off the finish but to keep it new it should be anodized again. PITA process unless you just want to paint and not worry about dirty aluminum again.

 

[Trackbolt]

Re: HELP with dirty aluminium!

I am doing almost the same thing. I used an aluminum coil cleaner for air conditioner coils which did a good job of removing tarnish and oxidation. My 1958 Alumacraft 15' was pitted from years of salt although there were no perforations. I use a heavy duty right angle grinder/sander/polisher and went over the pitted area with 6" 80 grit sanding pads. I then graduate up to 200 grit 320 grit pads and then begin wet sanding with 800 grit and graduate up to 1500 grit. I used an air palm sander to wet sand. It still is lots of tedious work. It was well worth it when I finished with the 1500 grit then used brown tripoli polishing compound on a terry cloth buffing pad on the right angle polisher. I tried the liquid and paste aluminum polishes and found the same thing that you did. Lots of black and not much shine. With the stick metal polishes like the tripoli, I brought the finish out to almost mirror perfect.
It took about two days (16 hours) to do half of the boat. (outside only) The worst of the corrosion was on the side between the top rail and spray rail. The bottom I just polished out without sanding and I went over it several times. I think that when I'm done I am going to give it several coats of clear laquer to preserve it. I don't think that I can afford to have it anodized.
Depending on whether or not you have pitting on the surface, you might be able to be able start with wet sanding at 800 grit and progress up to 1500 grit. This will save you much time.

Good Luck

 

[WaterWitch2]

Re: HELP with dirty aluminium!

For my aluminum rub rail of my '58 Glass Magic I started with #220 on a DA sander. It had some deep gouges in it. I forget how fine a paper I worked up to. I polished it on my bench grinder with a polishing wheel with a dry stick polish and it came out very nice. Here's a before and after pic.

 

[wire2]

Re: HELP with dirty aluminium!

A couple of points;

Polishing aluminum will ALWAYS turn a cloth/pad black, even a new, shiny piece.

Only the harder grades of extruded aluminum will buff to a mirror finish. Microscopically, the softer ones are porous, the holes fill with the black residue from polishing and look dull.
Cast aluminum is usually very porous.

Only harder grades of extruded aluminum will satisfactorily accept anodizing. Most automotive wheels will not.

Grades of aluminum; http://www.ez.org/aluminum.htm

 

[kanz]

Re: HELP with dirty aluminium!

Try this www.nuvite.com It worked great on my Tracker.


Jimmy