Buffing and Polishing Materials

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Taogem:

Almost any metal or hard plastic item can be buffed to a high polish or a satin sheen with the correct buffing wheel and the proper polishing compound. This includes copper pots, doorknobs, golf clubs and switch plates, to name a few common items.

The molecular composition of different metals is as different as the appearance, density and luster of the metals themselves. To polish and enhance the shine on a beautiful piece of jewelry requires a totally different set of polishes and buffs than to get a real professional shine on stainless steel or, aluminum or chrome. To polish 18k gold takes a different set of materials than those needed to polish platinum. There is no one all inclusive polish or buff. Six factors must be considered when buffing: equipment, buff selection, compound selection, technique, knowing the material being buffed and protecting the finished work.

This report is an attempt to discuss two of those factors, the different compounds and buffing wheels. We do this without picking a winner. A brief look at the Orchid archives on just one proprietary material (ZAM) shows the range of opinions on whether the material is a pre-polish a polish or a super polish. In polishing it appears that the old axiom "if you like it, use it", is still alive and well.

There are three generally used terms used by many in the jewelry and metal polishing industry that are often used interchangeably. It's not important which terms you use, but I present them for your information. The terms are deburring, polishing and buffing. The generally accepted definitions are:

Deburring
Deburring is the removal of all sharp edges, air bubbles and burrs on a piece.

Polishing
Polishing is the use of abrasives to get general surface finish improvement.

Buffing
Buffing is the step to get a smooth, bright, high luster final finish.

There are many different polishing and buffing compounds. Some people separate them into additional categories with 3 or 4 different levels of polishing and buffing. This is very difficult to do because the compounds are used for different reasons by different people depending on the buffing and polishing you are doing. The people in the aluminum wheel industry use many of the same buffing and polishing compounds as the people in the dental appliance industry and we in the jewelry industry use. But we use them differently depending on the work we are doing. Another often-used breakdown of compounds is:

Cutting Compounds
These include the brown Tripoli and bobbing compound

Intermediate Compounds
These include Gray Tripoli, Graystar, white diamond, and crocus. Platinum Tripoli and yellow bobbing compound.

Polishing Compounds
Some polishing compounds are red rouge, yellow rouge, white rouge, black rouge, green rouge.

Super Finish Compounds
Some would disagree that there is a super finish category, but there are those who believe that there is something above red rouge, so for this discussion we will include it. What is interesting is the range of materials people put into this group. They include blue rouge, Blue magic, Fabuluster, and yes even Zam.

Types of Abrasives
Abrasives are those materials used in operations such as grinding, polishing, lapping, honing, pressure blasting or other similar process. Abrasives come in different particle or grit sizes depending on how much material needs to be removed.

The following table is a general guide to the coarseness of various abrasive grit sizes.
Grit Size    Relative Coarseness
8-24    Coarse
30-60    Medium
70-180    Fine
220-1200    Very Fine

This table of grit size to micron size is for reference only. In my research I have found conflicting data on this topic especially in grit vs. mesh vs. micron sizes.
Grit:
100,000 (1/4 micron)
50,000 (1/2 micron)
14,000 micron)
8,000 micron)
3,000 (6 micron)
1,200 (15 micron)
600 (30 micron)
325 (45 micron)
220 (60 micron)
180 (80 micron)
100 (150 micron)

Materials used for abrasives are generally characterized by high hardness, and moderate to high fracture toughness.

Each hard abrasive particle acts like a single point cutting tool. With hundreds if not thousands available in a small area, the effect they produce is quite significant.

Coarser grades/grits of abrasive are used where high volumes of material need to be removed, such as in coarse polishing, large scratch removal or operations requiring significant shape or dimensional change. Finer grades are generally used after coarser grades to produce a higher surface finish than are possible with coarse grades.

Abrasive materials

Alumina or Aluminum oxide
Aluminum Oxide, both fused and calcined, produced from Bauxite. The most widely used abrasive, generally used for ferrous alloys, high tensile materials and wood.

Corundum
Naturally occurring alumna similar to rubies or sapphires.

Diamond
Most often used in ceramic grinding or final polishing due to high hardness and cost

Emery
Naturally occurring mixture of corundum, magnetite, a magnetic oxide, hematite and quartz. A light weight, glassy volcanic rock that is crushed into a powder for use in jewelry work Emery compound is gray or black in color and is used for coarse buffing and fast cutting action on stainless steel and ferrous metals producing non-polished finishes on metal.

Cubic boron nitride (CBN)
CBN, which is composed of cubic boron nitride grain and special ceramic binder, has excellent features such as high hardness and little chemical wear resistance. It has a structure and properties greatly resembling diamond.

Garnet
Usually used for machining of wood.

Zirconia/Alumina alloys
Suited to carbon and stainless steels and welds

Neuberg
Chalk Mined in Neuberg on the Danube, mild abrasive consisting of silica and alumina.

Silicon Carbide
Synthetic abrasive sometimes known as carborundum. Generally used for non-ferrous metals

Tripoli
Naturally occurring in the U.S.A., Spain and Italy, it consists mainly of a porous, decomposed siliceous rock, or diatomaceous earth, which results from the weathering of chert and siliceous limestone... It is a natural mineral classified as silica.

Vienna Lime
Consists of mixture of calcium and magnesium oxides - now rarely used.

Rottenstone
A light, porous, somewhat friable, siliceous rock used for polishing steel and Other metals. It consists almost entirely of silica, with a small percentage of Alumna and other impurities, and is derived from siliceous limestone's after the Removal of the calcareous matter. For woodworking, paraffin oil is used for lubrication.

Crocus
A ferrous oxide abrasive material consisting of coarse grains of ferrous or iron oxide that is used for grinding metal before polishing. Finer grains are called rouge.

Pumice
Lightweight, glassy volcanic rock that is crushed into a powder for use in jewelry work for producing non-polished finishes on metal. It should always be used with water for lubrication, and should also be rinsed frequently (for jewelry applications), for woodworking, paraffin oil can be used for lubrication.

Types of Oxides

Ferric oxide (Iron oxide)
Very little abrasive effect. When pulverized, washed and decanted, it is turned into crocus or red rouge for cutting and Polishing metal.

Chrome oxide (chromic oxide)
A green, insoluble powder (Cr2O3).Very little abrasive effect - used in green rouge.

Aluminum oxide (Alumina)
Very little abrasive effect - used in white rouge

Compound confusion

One of the difficulties in using and understanding rouge or abrasive compounds is that each manufacturer uses his own recipe to make the finished material. Most metal smiths also have basic knowledge of some of the terms used in lapidary work. Polishing finished stones is as difficult as polishing a finished piece of jewelry. Aluminum oxide is a material that is regularly used in lapidary polishing as well as metal polish.

There are two types of aluminum oxide used in lapidary polish, sometimes called "A" and "B". Because the brand name "Linde" used to be almost synonymous with high quality aluminum oxide, many people still use "Linde A" and "Linde B" to describe the two types.

Aluminum oxides labeled as "A" and "B" are not all equal in quality or performance. The size of the alumina particle is very different. Aluminum oxide "A" is 0.3 micron in size and Aluminum "B" is an extremely small micron size of 0.05. To put this into perspective, 50,000 grit is .5 micron and 100,000 grit is .25 micron.

When we purchase a bar of red, white or green rouge we have no idea of the amount of oxide used or the size of the particle used in manufacturing the bar. This can vary greatly from manufacturer to manufacturer.

One large U.S. manufacturer told me that they make six different green rouges all using chrome oxide. The range of oxide used was from 5% to 90%. That is a very large differential. If you have been using his 90% material and get a hold of some 40% material, you will not get the same results.

The same problem exists with all materials. Additionally synthetic materials like synthetic iron oxide are available. I have no idea of the difference in polishing characteristics between synthetic and natural materials.

Unfortunately this can drive you crazy when purchasing compounds. Buying at tool shows, flea markets and the internet is fine, just remember we have even seen bars of compound as coarse as a rough emery around, 200 grit, sold not only as jewelers rouge, but actually stated that it was suitable for use on precious metals. The product would destroy plate and damage gold in a minute. This is what happens when terms are generalized and corrupted. The moral is, stay with a consistent reliable supplier, generally then you will get consistent materials. Even if you buy material from another reliable supplier, the chances are that you will get a different composition material.

To add confusion, different suppliers describe some buffing and polishing compounds differently and many different brands are identical for all practical purposes. Not all compounds are jeweler's rouge, as many of us believe. Jeweler's rouge is made with ferric oxide, which gives it the red color. Rouge, is French for 'red', and even though it is then semantically incorrect to call green or white polishing compound rouge, we do it anyway.

Do remember that metals like gold absorb much of the ferric oxide when buffed and comes up a bold, bright gold color, if you use a black or white or green compound it will absorb the dye and not be the same color as the red rouge polished piece. That's O.K. if that's what you want.

Cutting Compounds

Bobbing Compound
Bobbing Compound cuts faster than Tripoli and clings well to the buff or lap. It is recommended for silver, brass and copper. Bobbing Compound is used with a brush or muslin wheel to remove scratches and fire scale. The yellow stick is greasier and will cut faster than regular bobbing compound. Leaves the item scratch free but dull.

Tripoli Compound
Tripoli in compound form is red/brown in color and is used to remove light scratches, imperfections, and oxidation on non-ferrous materials such as wood, aluminum, brass, copper and die cast metal. Medium cutting action. It is used as an abrasive for preparing jewelry work for polishing. The powdered stone is usually mixed with a binder and molded into cakes for easy application to buffing wheels. The most popular general compound for cutting down and buffing base metals. Gives a smooth, satin finish to copper, aluminum, pewter, gold and even hard plastic surfaces. Use Tripoli first to remove scratches and pits then follow with rouge for high luster. This compound is water based for easy cleaning in ultrasonic. Use with yellow buffs. Used for fast cutting action and some degree of color on all metals.

White diamond compound
A buffing compound made of tin oxide and a binding wax that polishes fast and provides a moderately high shine. It isn't made of real diamond dust. It is often categorized as a type of Tripoli. This is also different than white rouge. White Diamond Compound is used on brass, copper, aluminum, bronze, nickel, silver, gold and softer metals. May also be used on plastics. This compound will cut and gloss in one operation. This compound is water based. Finer than Tripoli, coarser than rouge. There are two classifications of white diamond, XXX White Diamond which is a superior dry compound for cut on gold, silver, brass, copper and plastics and XXXX White Diamond which has finer abrasives for better color, less cut and scratch. This polish is an excellent choice for use on ivory and bone where you don't want your material picking up the "green tint" common with most aluminum oxides. Use with yellow buffs.

Crocus Compound
Red in color because of the iron oxide, is used with iron and steel, and is fast cutting

Gray Star Compound
Made of very fine uniform aluminum oxide abrasive, produces a good cut with no wild scratches and works to good color on all metals. May be used for cut and color as one step, rather than two operations. There is also Gray Star 270 / A that is similar to regular Grey Star, but drier, with less cut and high color.

Buffing Compounds

Red Rouge
A product traditionally made of iron oxide, pulverized and graded, used in jewelry work. Darker-colored, coarser grains are called crocus and are used for grinding. The finer grains are called rouge (French for "red") and are used for polishing steel and precious metals. It is the finest of all rouges. Rouge is often mixed with a binder and caked into a bar form for easy application to a buffing wheel.

Green rouge
Primarily used in final finish buffing operations on stainless steel, steel, brass, aluminum, nickel, and chrome. The green rouge is a chrome oxide, and is considered the best all around luster compound for these materials. Green Rouge compound imparts a high luster to rhodium, platinum, chrome, stainless steel and other hard metals. 100% green rouge for superior final finish on steel, stainless and chrome.

White rouge
The white rouge is the softer, calcite alumna type. Primarily used in the final finish of steel, stainless steel, and zinc. This compound is also a favorite in coloring aluminum and brass. Use on platinum, chrome, and stainless steel. Produces a chrome color

Yellow Rouge
Aluminum oxide, yellow Rouge compound has a slight abrasive action combined with final finishing quality

Orange Rouge (Carrot)
There is an expensive orange platinum rouge, (apparently an alumina polish) made in Germany and sold by Gesswein,

Black Rouge
Black Rouge produces deep finish on silver and pewter. Excellent for oxidized effect in recessed areas. One company list alpha-alumina as the polishing material.

Zam
A proprietary mixture of aluminum oxide and chrome oxide with an unidentified binder. Produces high luster for final finish. Can be used on precious metals and steels, stainless and plastics. Clean working, leaves little residue; also works well with non-ferrous metals. Also polishes stones, epoxies and other soft metal materials. Zam has a burnishing action and it may remove detail if used heavily.

Blue Rouge
A product manufactured and sold by Dialux in France. It is advertised as a general purpose very high luster polish. Gesswein also sells a blue rouge that uses alumina as its polishing agent.

Fabuluster
Fabuluster is a proprietary compound utilizing alumina as its polishing agent

travelerga:
George,nice to know. good work.
mike

CosmicFolklore:
OK, here's the Michael Johnson technique and explanation :)  No matter how polished you get a work in silver, it will scratch. The higher glossed the polish, the more these scratches become evident and stand out.  High carat golds are the same.  I only recommend a high gloss on 14k or below and any white gold.  If not, your customer is going to either bring the work back frequently for you to re-polish or they will be dissapointed with their jewelry and think that sterling is a cheap choice for jewelry.  Actually sterling is just not meant to hold a high gloss.  Platinum is the hardest metal.  It's the hardest to polish, since you have to use very abrasive materials in succession, and it too when scratched will look very bad.  So, you will mostly see a low satin sheen on platinum by the most skilled jewelers.  


I was roommates with a Japanese student in grad school, who made swords as his passion.  He used very primitive finishing techniques on the silver used in the blade guards as well as the steel.  He used a sand first wetted and pulled across the metals.  Then he worked through several grades of pumice, and then a block of charcoal, then powdered charcoal.  

I now, sand with sandpaper to 600 grit, then I use powdered pumice mixed into a paste with water with felt burs on my roto tool. I use two grits; I'm not in the studio, so I can't read the grits on the jars, but they're the same as you'd use in a tumbler.  Then I use powdered charcoal worked with water to a paste.  Many jewelers have told me that charcoal would do absolutely nothing.  But, for me the proof is in the pudding, lol.  

I sometimes will use a wirebrush, sandblaster, or experiment with burs to get something other than a polish.  It adds  texture to make the design to contrast with the satin sheen to seem even more polished.

My goal is not to get a gloss or traditional polish which will show marks and places of worn polish with wear, but to make a consistently scratched surface that show the beauty of the silver colorations.  Scratches will not show as vibrantly.  I also use patinas, so this will enhance and pull out colors as well. The charcoal brings out a very satin finish.  And, it doesn't show everyday scratches.  The customer gets a work that will remain lustrous for years and years.  

After I put the finish on the work, I sometimes patina with one  of several recipes, and then fix it with Renaissance wax.  This is a microcrystaline wax that museums have used for decades, and it is a microscopic layer that can only be chemically removed or sanded off.  I have copper pieces that have kept its color for five years now.  I have complete faith in it.

OK, with all of that said, it really is a personal choice for each metalsmith.  However, when I have repaired sterling jewelery boxes, silver wear, or even antique jewelry in sterling, I use this finish.  And, the customers always remark that the polish is pristine, even though it isn't nearly as glossed as it was when they brought it to me.  I have only had about two to recognize the difference.  I WILL hit it with a rouge if they want, but I will also explain to them why I wouldn't suggest it.  

There are tons of ways to polish.  I won't put any of the others down,  But, I throw my shop's techniques out there for anyone interested :)

Bluesssman:
George, very nice! Thanks for sharing as I have seen a number of posts talking about polishing!


Gary

Taogem:
Quote from: CosmicFolklore on April 19, 2009, 10:07:02 am



There are tons of ways to polish.  I won't put any of the others down,  But, I throw my shop's techniques out there for anyone interested :)


Good stuff Michael.

Eventually, I am going to have to invest in a line of polishes including your suggested charcoal to compliment a silver polishing technique.

The last piece I did is plagued with scratches. Lots and lots for me to learn about this.

I also like what you said about "the goal is not to get a gloss or traditional polish which will show marks and places of worn polish with wear, but to make a consistently scratched surface that show the beauty of the silver colorations".

Thanks Cosmic  :)

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