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Need speed? Need faster production?
If you are a rock hound and have been to the various gem and mineral shows you have seen the polished Brazilian agate slabs and the polished rock book ends and similar peaces. You may not know that most of those are done with a Bull Wheel. You can grind, Sand and polish much larger peaces on a Bull Wheel than you can on other units and they are super fast. If you can hold it in you hands you can polish it with a bull Wheel. Bull Wheels were not produced for the several years but they are back in production again
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POLISHING JASPER
Jasper is much more troublesome to polish than agate because many varieties are "earthy" and porous and others contain hematite, which in itself is difficult to polish. If you are on a field trip, a good way to test for jasper is to wet it. If is absorbs the water and dries rapidly, throw it away. It will not polish. If it stays wet and does not dry right away, it contains a high amount of chalcedony and will take a good polish. Most jaspers polish well on leather with linde A, but good results can be obtained with tin oxide on either leather or felt. Always remember that a good fine sanding job is the secret of good polishing.
From Golden Spike News -
How to Cut Obsidian
Authocunknown
GOLD SHEEN: To get the most out of mahogany gold sheen obsidian, saw with the bands, as if they were a stack of plates, and you wish to unstuck them. Watch for "fire spots" in gold sheen. It is not plentiful, but opal like colors do sometimes occur in mahogany gold sheen.
IRIDESCENT: There are two types of iridescent obsidian. In cutting both correctly, the orientation of the color is most important. One type of obsidian is banded and the color lies in the bands. On the unbanded types of obsidian the surface has to be chipped to find the color. The banded type will have several colors or shades, while the unbanded types will have only one color. Cut the banded material parallel to the bands to get effect. To get a rainbow effect, cut the stone at an approximately 15-degree angle across the bands.
MIDNIGHT LACE: Lace-patterned obsidian should be cut across the surface pattern that you desire to reproduce. Although obsidian is comparatively soft, it is still very important to sand away all scratches before going to polish. Some advise that wet sanding be done, since obsidian is heat sensitive and very brittle. For final polish, felt with cerium oxide is the choice. Should you be faceting some particularly gemmy obsidian try cerium oxide on Lucite@, but keep it wet.
RAINBOW OBSIDIAN: Cut parallel to flow layers. These can be seen by examining fractured surfaces using an overhead single lamp bulb. As [the layers] are not always straight, it may be necessary to turn the stone slightly in the saw. Examine each slab set with either water or saw oil to see if the correct angle has been obtained.
SAFETY TIP: After obsidian is sawed, be sure to bevel the
edges all around on your fine grinding wheel to keep them from flaking and chipping. Wear goggles or glasses at all times. If a small chip of glass ( obsidian) got into your eye, it would be hard to remove as it is transparent and hard to see even with a powerful magnifying glass, and the edges may cut your eye to a great extent before it could be removed.
GRINDING OBSIDIAN CABS: Approach yourgrinding wheel with the material at a slight horizontal angle. If brought straight in, it may be a "shattering" experience, as obsidian fractures conchoidally and this is a sure way to do it.
POLISH ON OBSIDIAN: Keep the polishing wheel wet. A dry polishing will result in blisters and scratches. Obsidian is relatively inexpensive, easy to obtain and soft. With proper understanding of its glassy properties you can obtain some beautiful results.
-from Golden Frog, February 2005 Via The Rock Collector October, 2009 Via Strata Gem, November 2009 -
Improved Light Fixture
For all of you using Diamond Pacific, Genie, or Titan Machines, here is a story you can relate to. Have you ever been grinding away and had your hand slip and hit the rim of the light fixture? Ouch! Hot! That 75 to 100 watt incandescent light bulb is hot and really using up the electricity .Try to put one of the compact Flourescent Bulbs {CFB) in and they stick out the bottom of the light fixture causing all that light to go everywhere and not on your work. Then after a few days of use, the bulb breaks at the seams from all that vibration. The bulb is dangling from wires and the rest of the guts are still in the fixture with all that water splashing all around. Alas, I have found the best of both worlds. Try one of those small Halogen 35 watt mini flood lamps. It puts a real bright light right on your work, the rim of the light fixture stays cool and you are only using 35 watts to get better light than the 75 -100 incandescent bulb. When selecting the halogen bulb there are two sizes: one has a short neck, with will fit, but requires some creative twisting; the other style has a longer neck and will make the installation of the bulb in the fixture a breeze. So when that inefficient 100 watt bulb finally blows out, try a compact Halogen spot lamp as a replacement. Your work area will look brighter and you will be using less energy and running a lot cooler.
By John Marin via the CFMS Newsletter, 1012008
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