Purpose Of Buffing

Polishing and buffing are finishing processes for smoothing a work piece's surface using an abrasive and a work wheel. Technically polishing refers to processes that use an abrasive that is glued to the work wheel, while buffing uses a loose abrasive applied to the work wheel. Polishing is a more aggressive process while buffing is less harsh, which leads to a smoother, brighter finish. A common misconception is that a polished surface has a mirror bright finish, however most mirror bright finishes are actually buffed.

The removal of oxidization (tarnish) from metal objects is accomplished using a metal polish or tarnish remover; this is also called polishing. To prevent further unwanted oxidization, polished metal surfaces may be coated with wax, oil, or lacquer. This is of particular concern for copper alloy products such as brass and bronze.

The term chem-mechanical was coined to describe action of corrosive slurry on silicon in a polishing process. Multiple rotating heads, each studded with silicon wafers, get forced against a large rotating buffing pad, which is bathed in corrosive slurry. Material removal at elevated temperature progresses first through oxidation, then through oxide removal by abrasion. This cycle repeats with each rotation of a head. Potassium Hydroxide and Silox (white paint-base) can be combined with deionized water to form such a slurry.

 When To Use Buffing

Polishing is often used to enhance the looks of an item, prevent contamination of instruments, remove oxidation, create a reflective surface, or prevent corrosion in pipes Inmetallography and metallurgy, polishing is used to create a flat, defect-free surface for examination of a metal's microstructure under a microscope. Silicon-based polishing pads or a diamond solution can be used in thepolishing process.

 Process

The condition of the "metal" at hand determines what type of abrasive will be applied. The first stage, if the material is unfinished, starts with a rough abrasive (perhaps 60 or 80 grit) and each subsequent stage uses a finer abrasive, such as 120, 180, 220/240, 320, 400 and higher grit abrasives, until the desired finish is achieved. The rough (i.e. large grit) passes remove imperfections within the metal surface like pits, nicks, lines and scratches. The finer abrasives leave progressively finer lines that are not visible to the naked eye. To achieve a #8 Finish (Mirror) it requires polishing and buffingcompounds, polishing wheels and high speed polishing machines or other machine tools that can be used for polishing, like an electrical drill. Lubricants like wax and kerosene may be used as lubricating and cooling media during these operations, although some polishing materials are specifically designed to be used "dry." Buffing may be done by hand with a stationary polisher or die grinder, or it may be automated using specialized equipment

When buffing there are two types of buffing motions: the cut motion and the color motion. The cut motion is designed to give a uniform, smooth, semi-bright surface finish. This is achieved by moving the workpiece against the rotation of the buffing wheel, while using medium to hard pressure. The color motion gives a clean, bright, shiny surface finish. This is achieved by moving the workpiece with the rotation of the buffing wheel, while using medium to light pressure.

When polishing brass,(A softer metal) there are often minute marks in the metal caused by impurities. To smooth out the finer marks, the surface is polished with a very fine (600) grit, copper plated, then buffed to a mirror finish with an airflow mop.

Polishing operations for items such as chisels, hammers, screwdrivers, wrenches, etc., are given a fine finish but not plated. In order to achieve this finish four operations are required: roughing, dry fining, greasing, and coloring. Note that roughing is usually done on a solid grinding wheel and for an extra fine polish the greasing operation may be broken up into two operations: rough greasing and fine greasing. However, for inexpensive items money is saved by only performing the first two operations.

Polishing knives and cutlery is known as fine glazing or blue glazing. Sand buffing, when used on German silver, white metal, etc., is technically a buffing operation because it uses a loose abrasive, but removes a significant amount of material, like polishing.

 Equipment

Aluminium oxide abrasives are used on high tensile strength metals, such as carbon and alloy steel, tough iron, and nonferrous alloys. Silicon carbide abrasives are used on hard and brittle substances, such as grey iron and cemented carbide, and low tensile strength metals, such as brass, aluminium, and copper.

Polishing wheels come in a wide variety of types to fulfill a wide range of needs. The most common materials used for polishing wheels are wood, leather, canvas, cotton cloth, plastic, felt, paper, sheepskin, impregnated rubber, canvas composition, and wool; leather and canvas are the most common. Wooden wheels have emery or other abrasives glued onto them and are used to polish flat surfaces and maintained good edges. There are many types of cloth wheels. Cloth wheels that are cemented together are very hard and used for rough work, whereas other cloth wheels that are sewn and glued together are not as aggressive. There are cloth wheels that are not glued or cemented, instead these are sewed and have metal side plates for support. Solid felt wheels are popular for fine finishes. Hard roughing wheels can be made by cementing together strawboard paper disks. Softer paper wheels are made from felt paper. Most wheels are run at approximately 7500 surface feet per minute (SFM), however muslin, felt and leather wheels are usually run at 4000 SFM.

Buffing wheels, also known as mops, are either made from cotton or wool cloth and come bleached or unbleached. Specific types include: sisal, spiral sewn, loose cotton, canton flannel, domet flannel, denim, treated spiral sewn, cushion, treated vented, untreated vented, string buff, finger buff, sisal rope, mushroom, facer, tampered, scrubbing mushroom, hourglass buff, rag, "B", climax, swansdown, airflow, coolair, and bullet

The following chart will help in deciding which wheels and compounds to use when polishing different materials. This chart is a starting point and experienced polishers may vary the materials used to suit different applications.

 Purpose Of Plating

Perhaps the most common decorative metal plating technique is nickel-chrome plating. Master Finish Company specializes in this finishing process, in which a thin layer of chrome is applied over a layer or multiple layers of nickel plating.

For most exterior components requiring corrosion protection and wear, a bright nickel layer is plated over semi-bright nickel plating, and then covered with a thin application of chrome plating. This provides a hard, decorative chrome finish that can withstand the elements, and is very popular for parts that are exposed to the elements, such as in automobiles and motorcycles.

 When To Use Nickel Chrome Plating

Nickel-chrome plating can be used in the as-deposited condition or may be hardened, depending on the intended service conditions.

• Corrosion-Resistant : Specifically, the nickel plating process deposits a 12-15 percent nickel coating on the metals. This nickel plate resists corrosion, even at prolonged temperatures of 250 degrees Fahrenheit. nickel plate is reliable and uniform for use in electrical circuits. When sprayed with saltwater, nickel plate lasts 360 hours before the surface is corroded to a white appearance and 1,000+ hours before it rusts red.
• Durable, Scratch-Resistant
• Malleable and Polishes Well : Nickel is a shiny silver-white metal with a slightly gold tint. It is malleable and polishes well. Malleable nickel makes the surface of metal flexible for the creation of decorations, sculptures, and craft projects. it is not flammable and deposits do not easily form on its surface. Nickel-Chrome plated metal makes pipes for use in industrial and household plumbing.
• Conducts Heat and Electricity : Nickel-Chrome conducts heat and electricity When bound to metal, nickel-chrome plated is used by all the major automobile anufacturers to produce sturdy, scratch-resistant, heat-resistant cars and trucks. Nickel-chrome plated iron is used to create batteries with a long shelf-life and that conduct and store electricity longer and do not degrade after long hours of use. Nickel-chrome plated is also less expensive than other alloys.

 Purpose Of Plating

Chrome plating is the process by which chromium ions dissolved in water are electrochemically transformed into chromium metal atoms and deposited uniformly across a conductive metal surface. There are two general types of chrome plating: hard and decorative. Hard chrome plating applies a thicker, dull layer of chromium metal on top of industrial parts such as hydraulic cylinders, gun bores and rollers. These parts are made of hardened steel which, despite its strength, is poor at oil retention and other wear-resistant properties. Adding a layer of oil-retaining chromium solves these problems.

Decorative chrome plating is the type consumers are probably more familiar with: brilliant, smooth and highly-reflective

Chromium is a hard metal with a fine grain structure. This makes it ideal for protecting the engraved copper deposits applied to metals During press runs of any length hard chromium protects the metals from wear caused by paper and grit abrasion and, under normal conditions, enables the metals to print in clearer, sharper lines for the entire run.

Chromium plated metals also have greater corrosion resistance which protects the metal during storage and permits it to be put back into service quickly with minimum of preparation. Without the abrasion protection of hard chromium, metals wear quickly and the printing soon becomes distorted. Properly applied chromium deposits protect the engraving and extend its reproduction fidelity through several press runs.

This is possible because the normally poor micro throwing power of chromium plating baths enables them to reproduce the copper substrate surface exactly. Thus the engraving lines and patterns remain sharp and clear. This differs from plating solutions with good micro throwing power, such as bright nickel, which would tend to fill in the engraved lines. For this reason, special care must be taken to polish metals before hard chromium plating since the chromium bath will also reproduce any undesirable surface imperfections in the copper plating such as nicks and scratches.

 Advantages Of Electropolishing

• Brightening
• Burr removal
• Total passivation
• Oxide and tarnish removal
• Reduction in surface profile
• Removal of surface occlusions
• corrosion resistance
• Increased ratio of chromium to iron
• Improved adhesion in subsequent plating
• Reduced buffing and grinding costs
• Removal of directional lines
• Radiusing of sharp edges
• Reduced surface friction
• Stress relieved surface
• Removal of hydrogen

 Is Glass Bead Blasting safe for the environment?

Bead blasting is chemically inert and environmentally friendly. This method of metal cleaning is an acceptable method whenproperly controlled. The glass beads used in this process are made from lead-free, soda like type glass, containing no free silica that is made into preformed ball shapes. The glass beads can be recycled approximately 30 times.

 Benefits

Glass bead blasting is an effective process used in automotive restoration. Bead blasting produces a much smoother and brighter finish than angular abrasives. There is no dimensional change to the metal surface. Glass bead blasting leaves no embedded contaminates or residue. This process smoothes away any surface defects. You will be able to see every dent, stretch mark, file stroke, and every stroke of thesand paper. Glass bead blasting can also improve corrosion resistance.

 Purpose Of Plating

Tin Plating work improves corrosion resistance, increases the surface hardness of the material, provides a uniform and dense coating, and, in many cases, maintains the same surface finish the material had before plating. Tin Plating consists of the deposition of a Tin alloy onto the metal surface by a chemical bath, not by electrodes or external electrical charges. This permits the plating of hard to reach surfaces, such as small or deep bores and intricate shapes. Coating thicknesses for engineering uses vary from 0.0005 inch to 0.0015 inch

 When To Use Tin Plating

Tin plating can be used in the as-deposited condition or may be hardened, depending on the intended service conditions.

• For Corrosion Resistance
• For Wear Resistance in Hard to Reach Areas