Anyone know how to polish aircraft aluminum?

[FunkyZeit]

Got this stress plate from work for the base for my Barak. Wondering how to take the scratches off and polish it up?

 

Thanks

 

Justin

[Juggernut]

How deep are the scratches?  If the scratches are less than, I'd say 0.005" deep then you can compound them out with a coarse grade polishing compound, then buff the panel with fine compound then wax and buff it.  You'll most likely want to use a machine polishing wheel on the panel (at least for the initial compound) as hand compounding will be extremely time consuming and labor intensive.  The other side of this is that the panel needs to be securely mounted on something (or in something) so that the buffing wheel won't catch it and cause it to fly (without an engine).  When you apply and work the compound, it should turn to a dark grey/black color.  That tells you it's working.

 

If the scratches are more that 0.005" deep, then you'll probably want to sand them out using fine grade sandpaper (wet) 400-600 grit and then polish and buff as above noting that you may be able to skip the coarse polishing compound.  NOTE:  Prior to sanding the scratches, look closely at the aluminum; there should be a grain visible on the panel.  You'll want to sand with the grain and not against it.

 

When the panel is polished to your satisfaction, you may want to put a heavy coat of wax on it to keep it from oxidizing and turning dull (and it will).

[TonyT]

TonyT tip..

 

When you do polish it up, as with any metal you polish, use household flour afterwards, put it in the cloth you use to buff it up with and remove the polish, the flour will absorb all the black crud straight off the metal, saving you getting lots of rags black and saving you endless hours polishing to remove it......

[FunkyZeit]

Hey guys thanks!

 

They are not that deep but my structures engineer said it'll need a sanding. Is it possible to hand sand or an I better off using an orbital sander?

 

Also what kind of wax is suggested? Car wax?

Edited August 8, 2014 by FunkyZeit

[wunwinglow]

TontT tip duly noted, and circulated round the workshop! Many thanks indeed!

[alaninaustria]

Is that an actual inspection hatch from an aircraft? That will make a great base for yout F-16! I've seen the boys polishing up the aluminum birds at RedBull in Salzburg using circular disk polishers... If I may say... Just make sure you give a little traction to the surface on teh metal when you rest your bird on in... if the surface is too smooth there won't be enough traction for the wheels to properly grip the surface and you might stress the model's landing gear.... this happened to me with my Me 109 models on glass shelves...

Cheers

Alan

[Juggernut]

Hey guys thanks!

 

They are not that deep but my structures engineer said it'll need a sanding. Is it possible to hand sand or an I better off using an orbital sander?

 

Also what kind of wax is suggested? Car wax?

 

I would hand sand it keeping with the direction of the grain.   I would use automotive paste wax and put at least two heavy applications on and buff the heck out of it.  In the end, it should have almost a mirror finish.  Keep that cloth clean and keep rotating it until it's dirty across the entire rag.  Then get another rag and keep polishing until you've got what you want.  Clean out the holes in the panel with a cotton ear bud (Q-tip in the US).  As an added corrosion preventative, you might want to put a coat of primer on the back side of the panel that won't be seen.  That's entirely up to you but over time, the back side, if left untreated will begin to show signs of corrosion.  It'll show as white, chalky deposits on the surface of the aluminum and will eventually pit the surface.  I don't think it'll be seeing any kind of weather so putting the primer on the backside is just a suggestion; the corrosion you may see will be very minor and would take years to pit the surface of the aluminum (unless your intended display space has a continually high relative humidity level).

 

At the charter operation where I used to work, the guys would use polishing compound on the leading edges of our Gulfstream IV's to keep them polished up and shiny, like a mirror.  The downside is that the guys would turn black from all the polishing and would have to shower afterward and get fresh clothes.  One trip through any kind of precipitation, prolonged exposure to salt air or pollution would dull em up again so this was a continual battle.

Edited August 8, 2014 by Juggernut

[FunkyZeit]

Thanks for the replies!

 

I'm still on the fence with high polish or just brushed look, what do you guys think? I was also told about the leading edge polish, I just need to find an aircraft groomer when I land tonight!

[ScottsGT]

I've polished a lot of aluminum. Use power tools when ever you can to safe time and sore muscles! If deep scratches, start with a rough grit on a DA sander and progressively work your way up to finer paper. Auto body supply houses carry DA paper in the 1000 grits and up for wet sanding prior to buffing cars.