Metal Buffing Tips and Tricks

What is buffing?
Buffing is just the process of smoothing the minor 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 compound, and matching wheel, until you polish your piece to a near mirror finish.

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 more irregularly shaped objects like wheels and manifolds. Eastwood has other kits for other projects too, and they also sell everything piecemeal. All of these kits include the basics: Spiral and loose sewn polishing wheels, Tripoli, gray stainless, white rouge, jeweler’s rouge compounds and more.

Tips and Tricks

Before Starting – To quickly learn if a piece you want to polish is bare metal or has been clear coated, try cleaning the metal and polishing it by hand with some metal polish like Autosol or Simichrome and a clean white rag. Bare metal will always leave a gray or black residue on the rag, while clear coated or anodized pieces will not. If it is not bare metal you need to start by chemically or mechanically stripping it before you can begin any of the polishing process.

Organization – Use a 1 gallon or larger Ziploc bag to store your dedicated polishing wheels together with the compound you use with it. That way you don’t have to thoroughly clean out the compound every time to avoid contamination. Plus you avoid having emery or Tripoli scratch up a piece you are trying to polish with white rouge. Make sure to label the bags too.

Cleaning the Wheels – Even with dedicated buffing wheels a buff rake is a good idea to clean the compound out between jobs. You definitely need the rake if you are sharing wheels between compounds. You also want to avoid contaminating softer metals like aluminum and brass with particles of steel and iron by cleaning the buffing wheel between jobs.

If you don’t have a rake a large flat head screwdriver can do a similar job. Hold the edge of the rake or tip of the screwdriver against the spinning wheel and work it back and forth. The compound will be collected on the leading edge of the tool.

Maintaining a Polished Surface

If you are polishing something that will rust, like mild steel, you need to treat it immediately to avoid flash rust. For aluminum, brass or stainless steel it is not that big of an issue, but they will dull over time if not treated.

Autosol – This polish will leave a fine film on metal and keep it from tarnishing or oxidizing for a while, but it’s not weather proof. It also won’t stop rust.

Metal Protect Spray – Eastwood Metal Protect is an aerosol spray film that will protect metal and is nearly invisible. It is very thin and won’t change the finish while protecting from 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. It can be removed with acetone or Eastwood PRE paint prep if need be.

Diamond Clear Spray – The ultimate 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, 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.

Q & A
What is an anodized finish? – An anodized finish is basically a clear or tinted plating. Like a lot of plated finishes it works best on smooth, highly polished surfaces.

How much of milling marks can be removed by polishing? – On machined, spun rims and other milled pieces there will always be marks left from machining them. If you can feel the marks with your fingernail, chances are they are too deep to buff out. In that case the expander wheel and sanding belts, or greaseless compound is the place to start. If they are really deep you may need to start with a fairly rough grit sanding before moving onto finer materials.

How long can you use a buffing wheel? How do you know when you replace them? – Basically you can use the wheels until they start to fall apart. When the spiral sewn wheel wears down to the first circle of stitching it is time to replace it. Loose wheels will last longer, especially because the finer polishing puts less wear and tear on them. The smaller wheels and the buffs used in your hand drill will wear out faster.
How do you deal with the dust build up in your shop? – A lot of shops will dedicate a corner of the shop to buffing and polishing to try to keep the dust in one place. A curtain that surrounds the buffing wheel and work bench will keep most of the dust from contaminating the rest of the shop for the most part. For serious polishing and buffing shops an HVAC system can be used that will suck the dust up and filter it from the air.

Are there any metals that can’t be polished? – No, for the most part everything can be polished. Even a cast iron manifold can be polished to a smooth finish. Not every metal will attain the mirror like gloss that aluminum or stainless steel can, but everything can be polished smooth.

Any tips for polishing smaller parts? – The small buff kit, so use with a drill is a good choice for smaller parts. You can hold the small part in a soft jawed vice and work around it with the buff. Or for buffing the heads of things like stainless bolts, holding them in a pair of locking jaw pliers makes it easy to buff them on the larger wheel. Alternatively small parts can be polished in a vibratory tumbler with the appropriate media.

How often do you use the sisal wheel? – The sisal wheel is always step one for really hard metals, or rough castings with the greaseless compounds or emery. Be careful though because it can really take off a lot of material, especially on soft metal like sand cast aluminum.

Can you mount a buffing wheel on a normal car paint buffer? – Not really. The buff pad is made to buff with the edge of the wheel, not the flat surface. In order to use it with a buffer your have to hold the wheel perpendicular to the surface, which would be awkward and likely wouldn’t work very well. It is probably best to use the smaller wheels, or buffs and a regular corded drill.