BATT™
Owners' Instructions.
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The laps are hard enough to ring like a bell when struck, unlike pure tin or tin/lead...but they WILL bend if force is used to pry them off a spindle, or if they are dropped or stepped on, etc. Their unique grain structure is grown from the melt. Dropping them onto a hard surface can damage the grain structure of the metal so that if the "bump" is dressed or machined to a true surface, the damaged area may show different wear properties.. So handle them with as much care as your other laps.
The laps are cast and machined as simple disks. This way, they can be turned over for a second grit size, or can be resurfaced many times. Some faceters prefer using one side for diamond and the other for oxide polishes.
Choice of Polishes:
The new BATT ™ alloy has been tested with many aluminum oxide and cerium oxide suspensions. Origianlly developed for diamond, the BATT has been proven superior for use by "Oxide Fans". A light touch and low concentration is reccomended, because many of these polishes, and the aluminas in particular, can be fast and aggressive.
Soft regions accept grains of polish and can be readily charged with diamond or other polishes and abrasives, while hard regions maintain surface geometry needed for obtaining sharp meets.
Always charge the lap before cutting a first stone with diamond.
Load the lap well with diamond compound, or, preferably, diamond powder and a little oil to make a stiff paste. Polish a scrap piece of quartz, topaz, sapphire, etc, sweeping the lap to insure uniform spreading and abrasive loading. After a minute or two you will see the finish begin to improve as diamond is taken into the softer domains of the alloy. Metal being smeared on the stone, (or on any facet during cutting) is an indication that the lap is "seeing" the stone..Apply more polish (diamond, Cerium oxide, whatever you are using.) You can see an illustrated example on the Web at http://www.gearloose.com/charging.html
I originally began making these laps for diamond, but other users have found that superior polishes can be obtained with Aluminum or Cerium oxides-And if the polishes are used in an oily base, pre-charging is not needed! Some users with light-pressure techniques obtain good results with water-based slurries without charging. People report making their own polishes in light mineral oil with good results. Old traditional mixes of diamond powder in olive oil or peanut oil work well on the BATT Lap.
1: If using diamond compounds, charge well before using.
2: SWEEP THE LAP. When polishing a facet, move the stone from the inside of the lap to the outside. It is a good habit to develop for the following reasons: First, it spreads wear uniformly so the lap will break in and burnish well. Since the laps are made on a lathe, they have microscopic annular grooves, like a phonograph record. If the lap is swept, these grooves will not create an impression on the facet. Sweeping any metal lap allows it to break in better and last much longer.
3: USE LITTLE OR NO WATER. BATT ™ laps are designed for their low frictional value. Only a thin film of "dew" is needed for adequate cooling and swarf removal. Too much water wastes polish and wears the lap faster. DO NOT USE VINEGAR in the cooling water and avoid strongly basic materials such as silica suspensions. They both are harmful to the beneficial oxides on the alloy, or to the tin alloy itself. If you need a surfactant in the water, use Photo-Flo 200, available at a camera store at the rate of a drop or two a pint.
4: Developed for HIGH SPEEDS! Users report that speeds of 800-1,000 RPM on 8" BATT ™ laps produce excellent finishes without overheating. The User's transition from tin or tin/lead laps to BATT ™ is fairly easy. If you have never used a metal lap, experiment!
NO Vinegar!!! Please. Don't play with pH on metal laps, whether tin or bronze or iron. And never on lead-based (solder) laps. Lead acetate is soluble, and you will be breathing it! If you want a surfactant, use one like Photo-Flo 200 or Triton X-100. Dishwashing detergents contain "builders" (Sodium m-Silicate, etc.) which drive the pH in the opposite direction, and bases attack tin!
They will be less forgiving of agglomerates than the soft pure tin laps, but once charged, and run-in, do well. I mostly use them for diamond, myself. Usually when any new lap picks up metal, it means there is not yet sufficient polish into the surface. It took me a while to figure this out, and the first stone I did was an emerald. The flaws in the emerald were PACKED with metal! However, by the third stone or so, it never did it again. Another thing is that these -do not use as much water coolant...Do not flood the polish off. It is the polish which does the work, not the metal. It sounds simple, but it is not that obvious. Do NOT use vinegar. There is no need for it, and it will shorten the charge life. The metallurgy and surface characteristics have been optimized for oil or water, not acids. The oxides which normally form in use are hydrophilic already. If you continually etch them away with acids, the lap may never break in.
The following is drawn from case histories that have been solved by working with BATT owners: 1: CONTAMINATION:
Case 2: Cooling water in the drip tank was taken from a faucet during a drought. The well pump was pumping SAND.
Case 3: A person was cutting green Cubic Zirconia. Some synthetic materials are not well strain relieved. Tiny chips and flakes were coming off the CZ, and embedding in the lap.
Like graphite, diamond has a great affinity for rubber. The excess diamond will be plucked from the lap and will leave with the "eraser crumbs".
1: If you use a #170 grit to shape or preform the stone you will have to remove a MILLIMETER of material to get below the scratches, scores, and strains!!! The stone will look fine, all the way through prepolish, but when you begin to polish, you will see a particular type of scratch that is a line with an occasional "starburst" or fracture mark.
Think of how they cut glass in the hardware store! They score it with a cutting wheel or a diamond scribe. The strain on this line is so great the glass breaks cleanly all the way through. Look at such a scored line! Familiar? Doesn't it look JUST LIKE the scratches you are seeing from using a coarse grit early on?
If you have a #170 or a #180/220 "split grit" lap, and are not prpared to take off a lot of material with a #600 or #1200 THROW THE COARSE LAP AWAY or give it to a cabber. Often you may be surprised to find that a finer lap in good condition can actually cut faster because there are more diamond particles bonded to the lap per unit area. |