- Buffing & Polishing - Buffing Machines - Polishing Tools
Getting Ready to Buff - Surface Conditioning and Smoothing
Transform virtually any metal surface from a dull, rough finish to a lustrous shine! The key to that satisfying gleam is knowing where to start and understanding the difference between polishing and buffing. Novices often use the terms interchangeably. Polishing removes a heavy amount of material, such as during sanding or grinding, and buffing is the process that brings out the full brilliance of a part. Parts with dented or scratched surfaces will first require some conditioning before buffing can be effective. Here's how to prepare parts for buffing.
Difficult-to-replace stainless steel trim is a perfect example since it is almost never immediately ready to be buffed. Scratches and dings may be removed in a similar manner to dents on a car body, only on a smaller scale. Use a Trim Hammer to raise the dent, spiraling blows of the hammer in towards the center to minimize stretching.
Once the surface is relatively straight, there are five methods to make the part smooth enough for buffing. The most time-consuming is to block sand or file the part by hand, for the greatest control. Eastwood's Expander Wheel, used at up to 2400 rpm with premium grade 3M™ Trizact Expander Wheel Bands, will also level the surface and maintain the flatness of the surface without rounding edges. These bands serve the same purpose as our regular abrasive bands, except they are available in finer grits and cut more consistently throughout their longer life. Trizact Bands can be used to make relatively flat surfaces smoother quicker than any other abrasive, reducing buffing time. Edge marks on the part are virtually eliminated due to the softer construction of these bands.
For smoothing highly contoured surfaces, Eastwood's Greaseless Compounds are the most effective. These compounds are applied to either a spiral-sewn or loose buffing wheel. Available in 80-, 120-, 220-, and 320-grit, they convert your buff into a flexible grinding wheel. Tight access areas can be polished and smoothed with Eastwood's Abrasive Rolls, available in cylinder and tapered formats from 80- through 320-grit, used on tapered mandrels ranging in length from 2-3/4" to 6". Use the shortest mandrel possible since excessive side loading will more easily bend the longer mandrels. Felt bobs used with the greaseless compounds mentioned above present an alternative to using abrasive rolls.
The Vibratory Tumbler Systems
Eastwood's Vibratory Tumbler systems can be used for polishing and buffing small parts and are an effective alternative to hand-finishing. Vibratory tumblers work up to 25 times faster than rotating tumblers. Actual process time will vary from a few hours to a few days depending on the condition of the parts and the finish desired. Parts to be tumbled should be free of grease, oil residue and paint coatings. The tumbler load should consist of 30% parts to 70% media, without exceeding the maximum rated tumbler load. The pyramid-shaped Green Rust-Cutting Media is used in all our tumblers. Add enough water to just cover the media without creating standing pools of water. It usually takes between 5-12 hours to de-rust and clean moderately rusty parts. If a high shine is desired, the parts can then be placed in the bowl with the Dry Shine Media. This media will impart a high luster in 24 hours to a few days.
Which Buffing Motor is Right for You?
When selecting a buffing motor, a number of factors need to be considered. If the buffer is predominantly for buffing metal, choose 3600 rpm; if you'll be predominantly buffing plastic, 1800 rpm is preferred. More powerful motors yield faster results because larger-diameter wheels and/or multiple wheels can be used on the same shaft. The lower power motors will get the job done but take more time. For buffing light pieces of stainless steel trim, many prefer a smaller buffing wheel, which can be used on the small buffing motors or modified by making a small cut in all four directions around the arbor hole to fit the larger buff motors.
All of the buff motors we sell feature sealed cases and long shafts supported by ball bearings. The Eastwood Buffing Motors represent remarkable value and performance that nicely suit most hobbyist and professional needs. The Baldor motors have long been the industry standard for excellence and offer slightly longer shafts for improved maneuverability.
Mandrels and Adapters - Using an Existing Motor for Buffing
If you prefer to use an existing motor for polishing and buffing operations, Eastwood sells a wide variety of Motor Adapters to fit motor shafts from 3/8" to 3/4". The 1/2" and larger mandrels are available in right-hand and left-hand thread. To determine which thread you need, examine the unit to see if the shaft is to the right or the left of the motor. If your shaft is to the right, use a right-hand adapter; use a left-hand adapter if the shaft is to the left of the motor. The Wheel Arbor is used to mount our smaller wheels with 1/2" mounting holes to your drill or die grinder. If using this adapter with a drill, be sure the drill spins at least 2500 rpm or more. Low rpm will increase the difficulty of transferring compound to the wheel. For our Mini Buffs (1"-2" diameter) we have 2 mandrels - 1/4" shank and 1/8"shank. These two sizes allow the buffs to be used with most die grinders.
Getting Ready to Buff
Once the surface is smooth enough to buff (use 220-grit or finer for soft metals like aluminum, brass, copper and pewter; 400-grit or finer for steel and stainless), the buffing process can begin. As mentioned earlier in the polishing/preparation section, Trizact Bands can be used to substantially speed the buffing process. When using the A-30 (700-grit) and A-16 (1200-grit) bands on aluminum or other soft metals, use either Eastwood Tripoli compound or Eastwood Grinder's Grease on the Trizact band. Running these fine belts dry can pull grains of metal from the part and drag them across the surface, resulting in a rough finish. Using the Trizact bands saves substantial time and eliminates one or two buffing steps.
Buffers spin at a high rpm (usually 3600 rpm), which is more than enough to launch parts across the room or into you if the part is not held properly. Make sure to make contact with the lower portion of the buffing wheel (4:00 position when viewed from the left). The wheel should pass over corners and edges, not toward corners and edges. Hold the piece tightly and apply light pressure (about 2 lbs.) against the wheel. Do not insert your hand or fingers into openings. Practice how you will hold the piece against the wheel before starting the motor. Once you're satisfied you can hold the part safely, you're ready to put on your gloves, dust mask and eye protection and begin buffing. To apply the compound to the wheel, tear down the cardboard tube and hold the exposed compound against the wheel for about 2 seconds. You'll see how the wheel takes on the color of the compound. You'll also notice how the wheel turns black almost immediately when you start to buff. This black build-up is not harmful to the wheel or the part being buffed. Rake the wheel if you notice excessive metallic build-up, or do it at the start of the day to prevent scratching the surface.
As you progress from one compound to the next finer grit, remember to clean any residue with Eastwood PRE Painting Prep, Metal Wash, or hot water and detergent and change the angle by 90° (or as close to 90° as the configuration of the part allows). Before you stop to inspect your work, take a few passes with the direction of rotation. This technique will help remove fine scratches for a better shine. In the finishing industry, a "black finish" represents the highest reflectivity. If the buffed surface can reflect black without showing any fine scratches, then the best finish has been achieved.
Preserving The Shine
Buffed surfaces will stay oxide-free longer than rough metal, but in many cases the durability of the shine can be enhanced with the use of clear coats. Stainless steel, gold and platinum do not need to be top-coated with a clear, but brass, copper, aluminum, silver, pewter and most other metals will benefit from a clear coat. The most durable clear to use is Eastwood's Hotcoat Powder Super Gloss Clear. Some types of brass, bronze and steel can significantly oxidize when exposed to the curing temperature, in which case Eastwood's Diamond Clear Gloss for Bare Metal can be easily applied after degreasing for durable oxidation prevention.