I bought a polishing kit and I am making my first attempt at polishing aluminum. I'm currently working on an aluminum radiator shield and I've gone through all of the compounds but I am left with fine scratches. What am I supposed to use as the last step to get a mirror shine and get the fine scratches out? Should I switch to a liquid polish? Maybe I'm going at to fast of a speed? The drill can run at 3600 RPM's with no load. I'm using a drill with a 4" polishing wheel and using very little pressure. I've changed the wheel for each compound and washed the piece with degreaser with each change.
I plan on doing my plenum next but, I want to completly finish with satisfactory results before I get started on it.

The piece was sanded, then I use the following compounds in this order
Ebony compound
Brown Compund
White Compound
Red Compound

.....what should come next?

 

Use Mothers Billet Polish @ the end.

 

By hand or still using the wheel?

 

try hand first...

 

I've heard the Flitz buff ball works pretty well.

http://www.flitz.com/

 

if you plan on doind a plenum w/a drill or 4" bonnet, your in for a a whole lot of time, i have a professional polishing setup and use 10" bonnets some times 2 stacked next to each other. and it take me 8-10 hours to do a plenum. as they are very rough cast. check out my thread in the intake section. you will see the difference between my polished one and a factory one. threads titled night and day difference,check this out. you will be amazed. I'm always polishing something for someone, it just takes time to learn some tricks as in any other thing.

 

Thanks Guys.....I'm starting to think my expectations may have been to high.

 

just take a few days off work get a few 12 packs of beer and sit back and tell the wife to start polishing...

 

I always thought that if you want a GREAT looking mirror finish, you have to have stainless steel to work with!
here's a place where they sell the mirror/aluminum.... if your interested.
http://conceptzperformance.com

 

The whole trick to polishing is removing all of the scratches from the last level before moving on to the next level. I have had great results in the past going one step at a time starting with 220 wet paper and working though the whole range. But it takes a lot of time especially if working with sand castings and each time I do a piece I say "never again" because it is such a total pain.

Chris

 

I figured it out ....after a few hours of polishing, I need to go over the piece with a more fine sandpaper. I sanded it down and polished it but I still have a ton of scratches. I'm going to drop down to the 220 wet paper and give it a shot.

 

Only go down as far as you need to to get the scratches out, say try 600 a little first, if that wont do it, try 400, if 400 wont do it try the 240. From 240, you will still need to ramp back up to 400 and 600 (or one of your compounds may do the job for 400 or 600, I don't know what their equivalents are to sand paper).

These pics are of my last intake polish, other than a 6" wheel for finish buffing it is all done by hand. As you can see it is not very big and still it took me about 2 weeks of working on it every day in my spare time to get it this way. I recommend dish washing type rubber gloves or your hands will prune and turn black.

Chris

 

320 was the finest grit Home Depot had. I bought 400 and 320. Damn, this gets messy!

 

thanks for the pics. Any one else have any to post? Did you go over it with a clear coat?

 

320 is fine, if that will work to get out your scratches that is all you need.

I did not use any clear but the car never sees any weather so it will only need occasional polishing to keep it nice.

What I try to do is go the same direction with a particular paper as best I can (sort of like following the grain of wood). Then with the next paper step I go across the grain (creating a new grain direction), this way I know I have taken out all the scratches from the previous paper when all the scratches run the new direction.

Chris

 

The problem with polishing aluminum is you'll probably just polish off the oxide layer and it will grow back in a few weeks.

The reason aluminum doesn't really rust is because the oxide layer is pretty impermeable and very stable thermodynamically. Iron oxide (typical red rust) on the other hand is pretty permeable to oxygen and allows penetration and rust growth down into the bulk metal.

 

Steel wool is good for fine-finishing too. You should be able to fine 000 or 0000 at Home Depot in the paint section. It's about the equivalent to 800 grit or finer. It'll be alot easier to get in the cracks and such with the wool. (no water of course...rusts the wool) Follow-up with some Mothers or some other form of liquid polish. If you have a dremel, that'll make things go quicker in the tight areas as well. You'll just need to get thier little polishing attachments first.

It's definitely a lot of work. Something like what you're doing is so worth it though. You'll be like a proud father when you pop your hood.

 

I worked on this thing so long, I don't want to admit the time I spent. My neighbor and wife think I'm too ****, actully I am. I can't seem to get it perfect, maybe my expectations are to high. I thought I would be able to make it completly scratch free. It's a mirror finish.....just not completly scratch free. I tried to spray it with a clear coat but it didn't come out well. I'm going to polish it up and get the clear coat off, then it goes back on the car.

 

post some pics murphy...wanna see that sucker...

 

I tried to clear coat it, I didn't like it. Now I have to strip that off and polish it a little more, then pic's.....Like I said, I'm ****!