Friday, October 19, 2012

Vibratory Tumblers


by Janet Alexander
Technical Advisor




How is the Tumble-Vibe different from a rotary tumbler?

The basic difference between a vibratory and a rotary tumbler is the way the unit is driven.  A rotary tumbler consists of a barrel that sits on rollers causing the barrel to spin. Polishing media and the objects to be polished (jewelry pieces) are placed inside the barrel. As the barrel spins, the contents fall and slide over each other causing abrasion or polishing to the jewelry pieces located in the top 1-inch of the sliding media.  Jewelry pieces not located in the top inch are not polished. Some items can become dented due to the polishing media falling on the jewelry pieces.  It can take hours, days or weeks to bring a piece of jewelry up to a high shine using this type of unit. The lid on the barrel can leak or come off during the process.
 
A vibrating tumbler includes a bowl that sits on an out-of- balanced motor. As the motor moves, it causes the bowl to vibrate in all directions. The polishing media and jewelry pieces are placed inside the bowl. The bowl’s vibration causes the objects in the bowl to rotate around the bowl in two directions rubbing and polishing the jewelry 100% of the time. The items are polished much faster than a rotary tumbler and there is no chance of leaks, spillage, or denting of pieces. The items can be easily retrieved by opening the lid and fishing through the polishing media.

 A variety of different media, from cutting, to polishing, can be used in the vibratory tumbler including ceramic and plastic abrasives, walnut shells, and steel shot, making the vibrating tumbler more versatile than a rotary tumbler. The ceramic and plastic abrasives are sold in different grits. Polish is embedded in the walnut shell with the same polish jewelers use on buffing wheels. Steel shot, due to its hardness, is used as a burnisher. As it moves across the jewelry it rubs and burnishes the outer layer of the metal. 


General Instructions for the Raytech TV-5 Model
  • The working capacity* of the Tumble-Vibe 5 is approximately .05 cu. ft. (three pints) or 4 pounds. The capacity includes the media, water and the work pieces.
  • If the tumbler will be used for polishing as well as for cutting, always reserve one bowl strictly for the polishing media so it can remain free from embedded cutting grit.
  • Successful finishing of most jewelry requires preparing the jewelry. Parts must be filed, sanded, or ground smooth over rough areas. Attempting to finish jewelry parts without adequate preparatory finishing can result in very long finishing cycles and loss of detail in the jewelry pieces.
  • All plastic media or ceramic media should be broken-in before using. Media that is not broken-in may cause scratches. (See separate section, below, for breaking-in plastic media.)
  • Keep a 70% media to 30% jewelry ratio. Too many items tumbling at one time can produce a poor finish.
  • Always use cutting/burnishing soap with the media as required.
  • If using steel shot, fill the bowl with water so that it just covers the top of the shot. Never completely fill the bowl with water. Too much water or soap hampers the media’s action. After tumbling, remove and dry shot.
  • If using plastic or ceramic media, add 1 ½ oz. of water and a ½ teaspoon of polishing compound. Note: if the machine does not roll the media well at the start of a cycle, there is too much water or soap.
  • Change water if it becomes gray or loses its suds. Rinse the bowl and clean the media.
  • If the media tumbles too long without replacing the water, the jewelry pieces will absorb the gray sludge which is very hard to remove. The manufacturer recommends changing the water every three hours.
  • When using ceramic media, don’t allow the bowl to run dry. This will cause premature wear on the bowl.
  • Walnut or other shell media do not require water. Fill the bowl ¼” below the center cone and jewelry items.
  • On average, dry polishing media is good for polishing up to 200 hours of use. When not in use, store in an air-tight container. See manufacturer’s instructions.
  • Do not use media filled with silicon carbide or alumina powders as this will impinge and impregnated the metal surface and retard polishing.
NOTE: THE TV-5 UNIT CAN BE USED WITH UP TO 4 LBS. OF STEEL SHOT/CERAMIC MEDIA AND JEWELRY.

Breaking-in Plastic/Ceramic Media
1.   Place media into tumbler bowl.
2.   Add water and polishing compound /soap.
3.   Tumble without jewelry for one to two hours.
4.   Rinse media and bowl. Rinsing the media in a colander works well.

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