|06/24/11 07:29PM||Car Care, detailing, Polishing Metals|
Dr Detail Part 7
Details … Details … Details!
Rx: Polish Metals Like a Pro
Well done! You can finally stand back and admire your well protected paint and bask in the admiration of others. But … Wait! … Something is horribly WRONG! The paint looks great BUT the metal stinks! You can’t stop now. Nothing sets off great paint more than great Chrome (or Aluminum, or Stainless Steel). It’s like … like … like? I don’t know what it’s like. Maybe the way nighttime enhances daylight. Bogart brings out the best in Garbo. Ying accentuates Yang.
OK. Let’s get started. If the bright work is not coming off we’ll have to work with it on the car. Let’s first tape off the paint around the metal just in case we slip. 3M’s blue painters tape works just fine.
What shall we use to polish your baby’s hard stuff? Well there are basically four (4) types of metal cleaners/polishes.
1. Chrome Polish (targets hard metals)
2. Aluminum & Mag Polish (targets “softer” metals)
3. General Purpose Polish (untargeted)
4. Finesse Polish
Select and use the correct polish for the job. The targeted polishes do the best job on the metal they target. Aluminum & Mag polishes are not aggressive enough to do a reasonable job in a corresponding reasonable amount of time when used on hard metals but they work great on Aluminum and Magnesium. Correspondingly, chrome polishes are a bit too aggressive for “softer” metals but they can’t be beat on hard metals. General Purpose polishes do it all well but nothing great, still if you want just one product in your tool kit these are great. Finesse polishes are not very aggressive at all and will probably work too slowly to do the job all by themselves but as a final step? Wow!. And, finally, there are exceptions to all those rules!
Probably the best first step is to determine what metal you’re going to be working on. Grab a General Purpose polish for the test. With just a dab on your applicator, rub the part for a few strokes. Now, look at the applicator.
If its just dirty you have a few choices remaining.
A. The part is Steel, Stainless or one of their relatives
B. The part is coated and need a plastic polish
C. You’d know if it was painted
If, however, it is just about pitch black, you’ve got a layer of Aluminum Oxide on your applicator and your part is therefore Aluminum. Better yet, it’s polishable Aluminum.
Another option that you may run into is a anodize coating. These are hard but most metal polishes warn against their use on Anodizing. On the other hand, most of my customers with anodized parts want to strip it off. The Doctor recommends Caustic Soda or some product that contains Caustic. Easy Off oven cleaner is a convenient source of this chemical. CAUTION – RTL! That means “Read the Label”! Caustic (and Easy Off) are not to be taken lightly. It is best to remove the part before stripping anodize with this kind of material. Have some vinegar ready to neutralize it in the nooks and crannies that it will find.
Aluminum, Magnesium or other “softer” metals:
If you have Aluminum you may face a number of problems. Aluminum oxidizes and dulls. In the worst case it can corrode leaving pits filled with Aluminum salts. And then there are the usual culprits, scratches, nicks and dings (sounds like a law firm). Thin formed sheet Aluminum can be removed and worked with hammers and dollies just like body metal. Crumbly, oxide Aluminum can be initially cleaned up with a Scotch Brite pad or a similar Scotch Brite tool on a drill It may leave a few fine marks but they will come out. The residual pitting from oxidation, nicks and scratches will need to be sanded out. If you choose this route start with an aggressive paper that … “gets the job done in a reasonable amount of time.” … but then work the sanding marks down to a 400 grit finish. We’ll talk more about what to do after that, later when we cover “Cutting Metals”.
Now, a piece without the more serious problems can just be polished out. Grab a good Aluminum & Mag polish. Meguiars makes one called Hot Wheels that does a nice job. Mothers is also very popular. Or you might do just as well with a General Purpose polish. Wenol & Flitz make great polishes like that. In fact either one of those two will probably give you your best finish on any metal. Using a clean cloth, microfiber is NOT necessary here, grab just a dab of polish (most people use way too much polish) and begin to rub the metal in a linear direction, back and forth. Put some pressure on here since you are actually “working” the metal. A cotton tool in a drill does a nice job of saving the old knuckles.
Now, here’s where we Chemists get our chuckles. The first question from a customer after polishing Aluminum is, “I got all this black stuff on my rag. How do I get it clean again?” The answer is, “You don’t” Really, that’s Aluminum Oxide coming off the metal surface. That’s why we’re polishing in the first place, is to remove the oxide and get down to bare Aluminum again. You can wash your applicator all you want and it won’t clean up again, but you shouldn’t be concern about that. The part shines and the rag is dirty. All is balanced and right with the Universe.
If you use a tool on a power drill, you can build up a little heat. The tool will begin to glaze over. Now is the time to stop, reassess how much a “Dab” is and clean off the glazing. It won’t clean anymore and if it should transfer to your part it’s a bit difficult to remove. Clean up your tool with a wire or stiff brush (don’t try to remove the black color – read the paragraph above again) and grab another dab. Go back to work. Chances are you’ll never see the glazing when working by hand. Put the part aside until we’re through talking about hard metals, then read “A Billet Shine”.
Steel, Stainless Steel or Iron:
If your part is one of these, it can have it’s own problems. You may find some scratches but nicks and dings are less likely. If you find some follow the sanding steps detailed under Aluminum. The big one is that old demon, RUST! Steel and Iron will rust. Stainless is not supposed to but it all depends on how much Chromium was thrown into the mix. The more Chromium the less likely it is to rust. Rust can be removed with “0000” Steel Wool. “000” is OK too but my choice would be the finest. Steel Wool will knock off surface rust and leave little to no marks. If you have to get out the hammer and chisel to chip off rust scale, opt for another part, otherwise you may have to build it up again and reshape it. That’s way outside the scope of this “How-To”.
Now, grab a good Chrome polish. 3M makes a great one, their part number 39527. It will work better on hard metals than Aluminum polishes do. A power tool works best here. Polish in the same manner as with Aluminum, back and forth, until the desired finish is achieved.
There are such animals known as “Rust Converters”. The doctor loves them. If you have a rusty surface and you don’t want to polish it but rather paint the part, you’re in luck. Rust converters work like this … “Out with the old, In with the new” … or rather “Out with the bad, In with the good.” Rust is Iron Oxide. Another of those pesky “Oxide” characters. It is a combination of iron and moisture from the atmosphere. Rust does not only grow on the surface but the atmospheric moisture will keep seeping down past the rust on the surface to find more iron beneath. This iron oxide film (the rust) is active and accelerates corrosion by forming more iron oxide. Given sufficient time, oxygen, and water, any iron mass will eventually convert entirely to rust and disintegrate. Surface rust provides no protection to the underlying iron unlike the formation of patina on chromium surfaces. It just keeps building until all the iron is gone. However, if we change the rust, chemically, from an Oxide to a Phosphate we’ll actually form a protective layer that the moisture cannot get through and the rust problem stops.
Rust converters come in two varieties. The first is the more common, unfortunately. It is more a coating than anything else. You spread or paint it on and let it work for a day. But as a coating it has difficulty flowing out and leaving a nice, smooth surface. If later painted the uneven surface shows.
The second variety is just a liquid solution. Spray it on and wait the requisite 24 hours. The brown rust turns to black and you’re done. It is hard so it can be sanded down and when painted looks pretty good. Alternately it can be left as it is and it still looks good. Jasco makes a darn good one.
Chrome is also a hard metal BUT the similarity to Stainless and how it should be treated stops there. Especially in the later sections of this article under “Cutting Metal”. Chrome is a thin plating. If you mistreat it, it will pack it’s bags and leave town. Do NOT sand it for any reason.
Fortunately, chrome will have very few problems of its own. Contrary to many articles that you will find on the internet, Chrome does not rust. Rusting is the common term for corrosion of iron and its alloys, such as steel. Many other metals undergo equivalent corrosion, but the resulting oxides are not commonly called rust. Chromium forms a passivation layer of chromium oxide when exposed to oxygen. The layer is too thin to be visible, and the metal remains lustrous. The layer is impervious to water and air, protecting the metal beneath. Also, this layer quickly reforms when the surface is scratched.
OK, but you still want to clean it up, right? And why does it look rusty if Chrome doesn’t rust? Well, Chrome doesn’t rust and the Passivation layer can’t be seen, but the steel beneath it CAN rust sooooo the chrome plating must have been compromised in some way. Maybe it was scratched or cracked allowing moisture to find the steel beneath. Maybe the plating wasn’t continuous and the Chrome had pits or voids.
In any case, regardless of how the rust formed, take some “0000” steel wool, or better yet, Brass Wool, and knock off the rust. This fine a grade of steel or brass wool should not leave any marks. Then grab that dab of Chrome polish and go to work. What you’re trying to accomplish here is the cleaning out of the residual rust in the Chrome pits or cracks. Once it is thoroughly cleaned and polished, go find your paste wax and spread a thick coat on the metal. Sure you can wax metal! Fill in all those tiny little voids in the Chrome and lock the atmospheric moisture (source of oxygen) away from the steel. You might consider converting the minimal rust but you will leave tiny black specks instead.
A Billet Shine!:
For the finishing touch on any of these metals pick up some Simichrome, Wenol Ultra Soft (aka ex-Blue or ex-Auto) or even Mothers Billet polish. The finer the polish the better the shine. These are what the Doctor likes to call finesse polishes. Wenol got it right. They offer the red for quick work and the blue for the finesse finish. Use a soft clean fabric for these polishes and wipe down with microfiber, no matter how hard the metal is.
Cutting Metal – for the BIG problems:
Now, on to working the metal to remove scratches or finishing an etched or sanded surface. Typical compounds available to you and the professional are only capable of cutting a 320 sandpaper mark at best. If you have imperfections courser than a 320 grit mark it is best to remove them by sanding first.
You don’t have to go crazy here. Start with the finest grit paper that will efficiently remove the flaw in a reasonable amount of time. Move to finer & finer grits until there are no marks courser than a 400 grit sanding mark.
Sand in a linear direction, for example North and South. Move to the next finer grit paper. Use IT in a linear direction as well but perpendicular to the previous grit. If the previous was used North and South, use the next one East and West. The reason is that you need some kind of gauge of when to stop sanding. The first step’s gauge was the initial pits or imperfections, but with them gone, how do you know when to stop with the next grit? The answer is to use the sanding marks. There they are running North and South. When you sand East and West you will be able to watch them disappear. When you can’t see them anymore you know that you’ve reached the bottom of the courser sanding mark. Since the pits are gone why sand any deeper than the previous sanding mark? Continue alternating direction with each succeeding grit until there is nothing courser than a 400 grit mark left. Since the compound will take out a 320 grit you are assured of a flawless surface. That was step #1 but if you don’t have any imperfection larger than a 320 grit mark then skip step #1 and start with Step #2.
Step #2 is the compounding step. Use a wheel on a bench grinder, flex cable, hand grinder angle buffer, etc. Just make sure that you have a tool that is made firm enough so that you can pres against it while you’re working the part. A wheel can be spiral sewn cotton or any or several other assemblies using Denim or Sisal, a fibrous material similar to entry way door mats for cleaning your shoes before enter someone’s home.
Metal polishing compounds and rouges typically look like solid bars of material with a truncated pyramid cross section. These materials are formulated with animal tallow and therefore have a very low melting point. The melting point is so low that I have to be careful that they don’t melt away on me when outside on a hot day. Spin up whatever tool you are going to use and press the bar against it’s working surface. The friction will melt some compound and transfer it to the tool. Don’t try to turn the tool you’re using to a black or brown. You may have plenty on the tool even if you can’t see it very well. Now the surface treated tool can be taken to the part to be buff (or vice versa).
(CAUTION: I’ve had several former customers return to buy more compound, claiming, “I know I bought a bar from you but I can’t find it anywhere”. The Doctor’s response is always, “Do you have a dog?” Dogs are drawn to these materials and have been known to eat whole 3# bars in a sitting. If this happens to your dog it will probably have a very upset stomach for a while but it’ll usually be fine. Use common sense and take him to a vet anyway).
Buff the part with your treated tool until the tool starts to turn glossy and glazes over. The glazing will not cut and it can transfer to your part leaving a streak that may be difficult to remove. Stop and remove the glazing from the tool using a “Rake” or other stiff edge held against the glazed surface. Then retreat the tool and go back to work. Spend about 25% of your time dressing the tool. Proceed with this step until the metal looks faultless.
Step #3, and final, is to repeat step #2 only this time with a finishing rouge. Your part may look faultless but there are still micro-fine marks left by the compound that will need to come out to produce the highest gloss. Rouges do not cut much but the fine action of the rouge combined with the machining action itself will do the rest of the work for you. Rouging or “Coloring” the metal removes the finest of residual marks and messages the rouge into the pores of the metal to bring up the final brilliance and leave a protective layer.
Select a tool that is loosely assembled leaving it very soft. A wheel is typically only senw around the center arbor hole. These tools can not stand up to pressure. All you want to do is make contact with the part and the tre3ated edge of the tool.
Wipe down with microfiber between each step and wash with soap and water after the final step. You’re Done!
Tools can range from common cotton “Wheels” to shaped tools called “Tapers”, “Goblets” and Facers” each capable of reaching into odd recesses. All tools come in a variety of sizes from 1/8” shaft Dremel tools to ¼” shaft tools for drill chucks and collets. Wheels are typically mounted onto bench grinders but with the proper adapters can be mounted on a flex cable or rotary angle buffer.
I like to maintain polished metals with a paste wax. All you really need to do is to lock the surfaces away from atmospheric moisture to avoid dulling due to corrosion. Metals can also be clear coated for a long life. Just select a good quality clear that does not yellow. Finally, in hot areas, like under the hood, clears can be found in high temp. paints. Check out VHT formulas.
That’s the basics of metal surface care. We’ll still need to cover interior fabrics, rubber, vinyl, etc. but those will come a little later.
So let the shine begin!
Please submit your questions for this column at firstname.lastname@example.org and we’ll cover them in a future column. You can also submit your own testimonials and comments about the subjects covered here and we’ll try to publish them as well.
Thanx, until next week,