Metal Buffing & Polishing: Basics & How To

The Basics: What is buffing?

Buffing is simply the process of smoothing high and low spots on a surface until it is perfectly smooth. Typically it is done with fabric wheels and abrasive compounds of various types. You progressively move from a very aggressive, to a less aggressive grit compound, and matching wheel, until you polish your piece to a near mirror finish.

The Basics: Tools

To get started you will need a set of compounds and several polishing wheels, plus a motor to mount them to. If you are just starting out and don’t have anything Eastwood offers Item #13545 1/2 HP Buff Motor, Buff Shop Kit & Buff Stand for less than $250 that has everything you will need for most polishing jobs. Or order Eastwood Buffing Kit Item #50341, with smaller 6 inch polishing wheels, compounds and buffs and bobs to mount in your handheld drill for polishing irregularly shaped objects like wheels and manifolds. Eastwood has other kits for more specific projects too, and they also sell everything separately.

All of the kits include the basics: Spiral and loose sewn polishing wheels, plus Tripoli, gray stainless, white rouge and jeweler’s rouge compounds and more.

To make your life easier, and since the polishing wheels are not expensive, you may want to dedicate specific wheels to specific compounds and keep them together and labeled in plastic bags. That way you don’t have to worry about cleaning the wheel of all compounds before moving on to the next one.

The Wheels

Expanding Wheel – For starting out with extremely rough castings you’ll want to use an expanding wheel. This wheel has a rubber core center with some flexibility. Different grit sand paper bands are then attached to the outside of it. This combo is great for blasting through rough metal castings, especially hard metals like cast iron. The expanding wheel is used without any compound.

 

Sisal Wheel – The next common wheel, moving from rough to smooth, is the sisal wheel. Sisal is a rough, heavy cutting wheel good for iron, steel, stainless and other hard metals. This wheel works best with emery compound, or any of the greaseless solutions. It’s very rough and cuts fast, often as a first step on rough cast pieces.

 

Spiral Sewn Wheels – Now we get to the real polishing step. Most actual polishing is done with a spiral sewn cotton wheel and Tripoli compound. Spiral sewn wheels can come in different tightness; some have more stitching than others. The more stitching a wheel has, the stiffer it will be, and the more aggressive of a cut it will give you. The spiral sewn cotton polishing wheel is the real workhorse of the bunch; it is used for the majority of polishing.

 

Loose Sewn Wheel – For getting the really fine finish you want the loose section buffing wheel. In the industry this finish polishing is called “coloring”. Typically it is used with a white rouge polishing compound.

 

Canton flannel wheel – The most delicate wheel is the Canton flannel, used for really high polishing with white or jeweler’s rouge. Use it right and this wheel will leave a true mirror like polish on your project. Never use this wheel with anything but the white or jeweler’s rouge, or you will ruin it.

The Compounds

Greaseless – To start, if you have a rough as cast part, you are going to want a greaseless compound and a spiral or sisal wheel. The greaseless compounds come in grit ratings just like sand paper, and work very similar. They are for smoothing out the roughness of the casting before you even begin polishing. These compounds will start to melt if they get too warm, so keep them someplace cool, below 80 degrees.

 

Emery – The fastest cutting, heaviest abrasive compound is emery. It is usually a black of dark gray color. It’s great for hard metals like irons and steels.

 

Gray Stainless – Stainless compound is generally used for stainless steel, but can be used as step two on iron and other steels as well. It is typically also a gray color, but is much less aggressive than the emery. It works best with spiral sewn wheels.

 

Tripoli – This is the most commonly used compound, typically with a spiral sewn wheel. It’s the first step with most softer metals like aluminum, brass, copper and plated parts. Often times it is an orange/red or brown color. The Tripoli polishing step is where you really start to see the reflective sheen on the surface.

 

White rouge – The next step, and often the final, is the white rouge. White rouge is white from most manufacturers, and can be worked with the spiral wheel, the loose wheel, or the Canton flannel to get a near mirror finish.

 

Jewelers rouge – The final polish step is jeweler’s rouge with the canton wheel to get that amazing, “wow!”, mirror finish. Jewelers rouge is typically red or maroon.

Blue rouge – There is also a blue rouge for polishing plastic. With a spiral sewn wheel this is great for getting the scratches out of things like Lexan windows.

Safety Gear

When buffing you are working with a wheel spinning at several thousand RPM, so it is important to consider the safety aspects. If you don’t work the wheel right you work piece can snag and get thrown back at you. Besides that, any loose clothing or long hair can easily get wrapped up in the buffing motor. So wear a hat or tie long hair back and make sure your cuffs are tight and your shirt tails are tucked in.

Buffing will produce dust and dirt which you want to keep out of your eyes, nose and mouth. So safety googles, a face shield and a dust mask over your nose and mouth are the suggested minimum to be safe. Buffing and polishing will produce heat too. For that reason, and others a pair of leather work gloves are also a good idea.

Polishing Wheel Safety

One last word about safety, while buffing the safe area of the wheel to use is the lower half. If you try to buff with the top of the wheel a snagged object will get thrown right back at you. When you buff with the lower half objects tend to be thrown down toward the floor, or back away from you, which is much safer.

How to Buff

Now that you know the tools and compounds involved, and have the proper safety gear it’s time to start buffing. The process is similar for all the compounds and wheels, so we are going to start with an aluminum piece that is already a finished casting, a tight spiral sewn wheel and the Tripoli compound.

1. Take the tube of Tripoli compound and with the wheel running, hold it against the wheel for a few brief seconds with light pressure. Move the tube from side to side to make sure you get compound on the whole wheel. It is better to apply a little compound often than to put on too much compound all at once.

 

2. Buff the piece you are working on, again, using the lower half of the wheel. Press the piece against the wheel with light pressure and work it slowly back and forth.

 

3. Always work with the edge, not against it. Turn the piece so the motion of the wheel is parallel to the leading edges you want to polish, not perpendicular.

4. Apply more compound periodically as needed.

5. If you get a greasy black build up on the surface you have too much compound on the wheel. Eastwood PRE paint prep will remove the excess compound from the piece. Then use a rake, or flat head screwdriver to pull the compound out of the wheel.

 

6. Work until the entire piece is a uniform level of polish before moving on to the next compound and wheel.

7. Use a microfiber cloth and PRE to clean any residual compound off the piece before using the next finer paste.

Drill Buffing

For more irregular shapes, and smaller detail areas, the drill mounted buffs are a better choice. These allow you to get into tighter areas like on an intake manifold, or inside the cut outs of alloy rims. Polishing with them is the same process, but you typically mount the work piece and hold the drill motor.

1. For best results use a corded drill with a locking trigger and variable speed settings. Typically you want to spin the buff at between 2000 and 3000 rpm.

2. Load the compound onto the buff the same way you would with a wheel.

3. Spin the buff and work it back and forth on the piece you are polishing. The conical and mushroom shaped buffs are great for getting into tight spots, and polishing items too big to work on the wheel, like alloy rims.

Maintaining a polished surface

Autosol – Once you have put all the time and effort into getting this highly polished surface you must maintain it properly to keep it that way. The simplest thing to do is polish it regularly by hand with a product like Autosol. This will leave a thin protective film on the surface and keep it from oxidizing and losing its luster. However it isn’t very durable, or very protective and it won’t stop rust.

 

Metal Protect Spray – A more protective coating can be had with Eastwood Metal Protect spray. This is an aerosol spray film that protects metal and is nearly invisible. It is very thin and won’t change the finish while preventing oxidation, tarnish and rust. It is fairly weather proof and can last for over a year of daily driving. Spray 2 or 3 thin dust coats to make sure you cover the metal fully.

 

Diamond Clear Spray – The ultimate protective coating is Eastwood Diamond Clear spray. It is a glossy clear coat paint designed specifically to be applied to polished bare metal surfaces. It will dull highly polished surfaces a little bit, but it is a nearly permanent protectant. There is also a satin finish for protecting bare metal that you don’t want to look fully polished forever, like brushed stainless or raw steel.

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