I finally figured out how to file, sand and buff Aluminum going from
coarse to finer abrasive tools and materials, and have achieved some
decent results. Problem is, once you finally reach that mirror-like
luster, HOW do you preserve it? Sure you can spray it with clear lacquer
like I did, but under the exposure of the heat in the engine bay, it
slowly but surely takes on a yellowish cast. I thought about clear
powder coating, but have heard that it just doesn't carry over the shine
of the Aluminum and looks dull. True? False? I don't know too much about clear ceramic coatings like they now have for other components, so I was hoping someone in the forum has an answer or could share the upside/downside of whatever they have tried... I'm all ears....

 

I have really like the results from Mothers polish and the powerball and then used a wax to help preserve the shine.

my $.02

 

It's been my experience that polish, (as in wax) only is good for a couple of weeks and burns off the engine's Aluminum in no time. First rain that comes along, I started to see oxidation. Here are some shots of my engine, along with some "in progress" , B & A (Before & After) shots with an extra manifold system for my VG.


Note in the image above all casting flash edges have been removed, including the
"ribs" that appear in several places.


Above, a detail shot of the partially reassembled engine.



Here's a side by side of the inlet, (B & A ).



Above, an overview of the engine and trani. Even the heat shields polish up pretty good! The transmission only received a quick working over with various grits of sandpaper. Be sure to cover any openings before you do this with the transmission out of the car so you don't get any grit inside!

Here's a close up of the trani, with minor sanding and work with a stainless steel
wire brush wheel in my electric drill. Surprisingly good results.

1989 Maxima GXE: Mods are, American Racing Equipment 16 X 7 AR-298's, mounted with 245-50-ZR16 Gatorbacks. The rear wheels required a 1/4 inch spacer to clear the struts and about 3/8's of an inch ground off the inner lip of the fenders. I want to lower the car about 1-1/2 inches because it looks a little "tall" with the larger rims. 245's seemed a bit too wide on the 7 inch rims, so my next set of high-performance tires will be 225-55-ZR16's.
Other mods:
Complete ported and polished and blueprinted VG30 inlet, intake manifold(s) and heads, 1990 300ZX injectors and a K&N filter kit from Stillen, also a "Tornado" turbine unit inside the inlet (as seen above). And it passed California smog too.

 

Very nice work!

 

Thanks! The frustration comes from doing it all by hand, most of that on my bench, then reassembling it with no guarantee of keepin' it nice and protected from corrosion, etc. Thus the reason for my original Q: How do you best maintain the shine once you've got it?

 

looks good but you are not finished yet. Its not mirror like in those pics.

Your next step is to get a buffing wheel and jewelers rouge to polish it to a mirror shine. Then to keep it that way just go over it all with an aluminum polish every now and then.

There is a clear you can use on them that will stick (made for aluminum and chrome where there is no sanding scratches to mechanically hold it) but its rather expensive. Its made by alsa (link here)...they have a video of all these tests they did on it showing how it doesnt flake off like other clears.


here is an example of some aluminum pieces I polished with a wheel and rouge (after sanding).

 

For polishing, I would start with sand paper that is gritty enough to remove any deep scratches or casting marks (~220 grit). Then, once the imperfections are removed, I'd slowly work my way up, in steps, to 1000 grit (for example 220, 320, 400, 600, 800, and then 1000). You'll know that you're ready to move on to a finer grit sandpaper when you have removed all of the scratches made by the sand paper that you previously used.

Then you'll need a bench grinder or a drill, some polishing wheels, and some rouge or polishing compound (I'd get the wheels and rouge from a jewelry supply store). You'll need one rough polish wheel, one rough polish rouge, one high polish wheel, and one high polish rouge.

Once you have sanded the piece of aluminum down to 1000 grit, buff it with the rough polish wheel and rouge, wet sand it with 2000 grit sand paper, then buff it with the high polish wheel and rouge. If you've done everything properly, it will look PERFECT (NO scratches, or blemishes) and it'll look SO shiny.

To protect it I would do what Michael recommends.

 

[quote=Michael;6197857]looks good but you are not finished yet. Its not mirror like in those pics.

Your next step is to get a buffing wheel and jewelers rouge to polish it to a mirror shine. Then to keep it that way just go over it all with an aluminum polish every now and then.

There is a clear you can use on them that will stick (made for aluminum and chrome where there is no sanding scratches to mechanically hold it) but its rather expensive. Its made by alsa (link here)...they have a video of all these tests they did on it showing how it doesnt flake off like other clears.

Hey, Thanks, Michael! Yeah, after seeing the parts shown in your link, I have to agree! LOL. Not quite THERE. It looks like the difference may be the wet sanding with 1000 grit then the jeweler's rouge. The parts in your link are indeed impressive. Definitely show quality. I will check out the Alsa clear coat too, because I have some Aluminum rims that need a touch up too.

 

Anyone try the Alsa clear coat directly over Aluminum?

 

I dont know anyone that has tried it period but their demo makes it look like a quality product. You just never know what you get though...honestly I dont know how they can have a product that sticks without a chemical (like sealer to topcoat) or mechanical bond (sand scratches).

I will look on some of the paint boards and see if I can find some references to it.



Keep in mind also that if you got this product you would need a way to apply it (spray gun) or pay to have a painter apply it.

 

Thanks, Mike.
The spray gun and compressor aren't the problem. Got that covered. But like yourself, I wondered if this clear coat REALLY COULD be sprayed right over bare, polished Aluminum. I assume of course that the Aluminum has to be completely cleaned of any wax, polish or other types of residue in
order to stick. Maybe it has it's own "bonding" capabilities-- something like acid-etching primer. Tomorrow, (Monday), I plan on calling their tech line and asking that question. Once I have the answer, I'll post it here for everyone's benefit.

 

I called ALSA's toll-free phone number (see contact on their website) and got a fellow by the name of Gary on their sales/tech staff. Very helpful. His recommendation for preserving the luster of your highly-polished Aluminum parts is a product they call "Clear for Chrome". It is a two-part catalyzed clear coat. It is not available in a spray can. Spray gun only. It will work with standard HVLP (High Volume Low Pressure) spray equipment. The least expensive quantities available are 1 quart base for $109.00 and the Catalyst, (several ounces) is around $29.00. The ratio of mixtue is under 4:1 and dries to the touch in an hour or two. For best results, he suggested baking the parts after two coats for 6 hours at 140 degrees. I asked him if the heat of the engine bay would accomplish pretty much the same thing and he said yes. The product was originally designed for coating and protecting chromed parts. It has a very high durability against nicks, abrasions and chemicals. I plan of giving it a try very soon, (budget permitting) and will review the product once I have used it in a new thread.