Anyone who has found beautifully rounded pebbles, shiny fragments of glass, or highly polished shells on a beach has seen how continual fine random abrasion can shape and polish even the roughest shapes.

Of course, in your studio, you don't have a private beach, a tidal system, manageable waves, and five years to wait. Fortunately, rotary tumblers and magnetic polishers are 50 000 times faster, yet cost almost nothing to run.

THE KITIKI ROTARY TUMBLER

A rotary tumbler has a revolving drum filled with water and irregularly shaped stainless steel shapes or abrasive grit. As it revolves, the metal pieces or grit particles repeatedly fall onto the material to be polished and the collective tiny impacts and scratches gradually burnish the surface.

If this is your first interest in tumblers, the practice of cutting and polishing stones, minerals, and gems, is called lapidary. Tumblers are sometimes called lapidary tumblers, and polishers are sometimes called vibratory or oscillating polishers.

The Kitiki Tumbler Kit 1 can be used for Art Clay and silver. It consists of a motor base, a full-size rubber barrel, 1kg of mixed stainless steel shot and burnishing shapes, and a pot of barrelling compound to keep the drum clean.

The Kitiki Tumbler Kit 2 can be used for stones and glass. It consists of a motor base, a full-size rubber barrel, 200gms of 80 grit, 200gms of 220 grit, 150gms of 400 grit, 150 gms of cerium oxide polish, and one pack of plastic pellets.

Although you can buy tumbler bodies separately, and shop around for the parts that make up the kit, it will be more expensive than buying the kit. Especially as, within the UK, there's no delivery charge.

If you've been researching tumblers, check for rubber feet, a nylon re-inforced drive belt, rubber barrels, easy-open lids, rubber rollers, stainless steel shot, gallay compound, grits and polishes, and a quick service for spares and accessories.

A FULL-SIZE BARREL

The tumbler will accept one full-size barrel or two half-size barrels, so that you can leave one on for a long time but use the other with different abrasives or for shorter periods. The full-zize 1400gm barrel is 135mm x 115mm diameter, and the half-size 700gm barrel is 75mm x 115mm diameter.

If you want to use two half-size barrels at the same time, they sit on the tumbler body with both lids facing outwards. Don't get them muddled if you stop the tumbler to check for progress. Many people prefer to use a separate drum for the final polish in case stray particles of grit scratch the finished surface. Put coloured dots on them?

The drum lids have several parts: an inner lid, a rubber O ring, a metal cap, a washer, and a plastic knob. To prevent any leaks, make sure that they're kept clean and are re-fitted carefully.

Tumblers that use plastic drums are usually very noisy and need to be left running well away from your work area. Also, the lids can be difficult to open, and often need to be stood in hot water to free them: with the risk that, as you manage to pull the lid off, you'll spill your work, shot or grit, and soapy water.

SHOT TO BITS

The stainless steel shot, included in some of the rotary tumbler kits, is not just round but a selection of shapes, such as pins, planetoids, and spheres, designed to deal with the range of contours on jewellery.

Although the shot is 100% stainless steel, don't leave it lying around wet: either leave it immersed in the tumbler mix of water and cleaner, or rinse it and dry it carefully.

When you open a new packet, do it over a bowl. The shot is surpringly agile and will easily escape, go on the floor, and roll everywhere. Either brush it up, or use a magnet: then wash it.

When you've finished, empty the shot into a cloth-lined sieve, rinse it thoroughly, and spread it on some cloth to dry. Don't accidentally flush away any shot as it will collect in the basin trap.

Stainless steel shot is quite expensive, and heavy to post: extra shot can be included, post free, with your tumbler. Don't buy plain steel shot: unless you're meticulous about cleaning and drying it every time you use it, it will soon rust and ruin your work.

Grit is the generic name for particles used to polish and grind. The grit that comes in The Kitiki Tumbler Kit 2 is silicon carbide: a hard, sharp, angular material. In use, it fractures into smaller angular particles, so is a very effective abrasive. Grit sizes are rather confusing: for example 400 grit particles are not half the size of 200 grit particles. You learn, through use, which grit to use for different materials, shapes, and finishes.

Grit should be handled and stored carefully to prevent contamination from stray larger particles that will scratch. Keep the tubs sealed until you need to use them. In use, transfer a small amount into a working container, to minimize the risk of contaminating the whole tub. And wash the drums thoroughly before and after use.

When you've finished, empty the grit into a cloth-lined sieve, rinse it thoroughly, and spread it on some cloth to dry. Be careful not to flush away any grit as it may collect in the basin trap.

CLEANER AND LUBRICATOR

Barrelling compound, sometimes called gallay compound, is a special solution used to keep the barrel and shot clean, lubricate the tumbling, help the polishing action, and minimise rust. The large drum, the 1400gm size, needs about two dessert spoons: the smaller drum needs one.

As you need to replace the liquid every few sessions, the Art Clay Kit includes two pots of barrelling compound, so that you won't run out just as you're becoming an expert.

Cerium belongs to the group of elements known as the rare earth elements. To produce the polishing powder, about 80% of cerium oxide and 20% of other rare earths are used, resulting in a pink-ish powder.

As polishing is the final step in the surfacing process, don't expect to remove marks or scratches made during previous steps shaping or finishing.

Although you can use various abrasives to polish your work, a tumbler produces a really even gloss finish, and hardens the surface, whilst you do something else.

Before starting, wash new or used barrels thoroughly using a brush and some mild detergent, and rinse them clean. This is particularly important as one left-over particle of broken stone or unwanted grit, tumbling for several hours, will leave scratches that are difficult to remove.

Measure out the stainless steel shot: about twice the volume of the silver. Put the shot in the barrel, then your silver, then two dessert spoons of barrelling compound, and then enough water to cover everything. The tumbling action won't work if the barrel is full, so never fill it more than about 70%.
Fit the lid, put the drum on the rollers, and start the tumbler. Try an hour, and then longer if you think that the finish can still be improved.

Empty the contents into a cloth-lined sieve over a bowl to save the liquid, rinse the silver and shot under the tap, and remove them carefully. Don't accidentally flush away any shot as it will collect in the basin trap.

Wash your pieces, wash the drum, spread the shot on some cloth to dry, and tidy up. The liquid can be used several times but, if the silver begins to look dirty or tarnished, it needs replacing.

Anyone who has found beautifully rounded pebbles or highly polished shells on the beach has seen how continuous random abrasion can shape and polish. Although tumblers provide continuous and distributed abrasion rather than intermittent and scattered abraion, and the grits are very hard and sharp, it still takes days or even weeks.

Before starting, wash new or used barrels thoroughly using a brush and some mild detergent, and rinse them clean. This is particularly important as one left-over particle of broken stone or unwanted grit, tumbling for several hours, will leave scratches that are difficult to remove.

If the stones have broken edges, you may need to use 50% more 80 grit. If the stones are already fairly smooth, you may be able to skip the 80 grit phase.

Select stones which are of similar hardness. Fill the full-size drum about 70% full with the stones, add two heaped tablespoons of 80 grit, and top up with water to about 10mm above the tops of the stones. Fit the lid, put the drum on the rollers, and start the tumbler. It's OK to stop the tumbler and check the progress, but the stones may need several days or even weeks. 80 grit breaks down gradually, so the stones might need another couple of days with new grit.

Empty the stones into a cloth-lined sieve, rinse them, remove them, and throw away the grit if it doesn't feel sharp. Don't mix up new and old grits. Don't accidentally flush away any grit as it will collect in the basin trap. Wash the stones, wash the drum, and tidy up.

Before moving to a finer grit, check the stones. Any imperfections that have not been ground away by now will be very hard to remove during subsequent tumbling.

Repeat the filling process, using 220 grit, and tumble for several more days. Again, it's OK to stop the tumbler and check the progress, providing grit doesn't prevent the lid sealing properly. Wash the stones, wash the drum, and tidy up.
Repeat the filling process, using 400 grit, and tumble for several more days. Wash the stones, wash the drum, and tidy up. Any grit remaining will produce scratches during the polishing phase.

Repeat the filling process, using plastic pellets to about 10mm above the top of the stones, but no water. The pellets buffer the fine cerium oxide polish. Add one tablespoon of cerium oxide that's been mixed with just enough water to make it creamy, and tumble for several more days.

Empty the stones into a cloth-lined sieve and rinse them. The pellets float, so you can skim them off. Wash the stones, wash the drum, and tidy up. Let the stones dry naturally.

Use plastic spoons to transfer the stones, particularly before the final polish, as metal can leave marks which are quite hard to remove.

THE KITIKI MAGNETIC POLISHER

A magnetic polisher has a stationery drum filled with water and thin stainless steel pins. An oscillating magnetic field makes the pins jump randomly and, as before, the collective tiny impacts gradually burnish the surface. Although more expensive, it's quicker and better.

Compared to a conventional rotary tumbler, it's much faster, easier to fill, quicker to empty, and simpler to clean. But it costs more.

The Kitiki Magnetic Polisher Kit 1 can be used for polishing jewellery, and metals such as silver, gold, and copper. It consists of a magnetic oscillator base, a separate acrylic drum, a plastic lid, a pack of tiny stainless steel pins, and a spare fuse.

The whole unit measures 103mm x 103mm x 230mm, and weighs just over 2Kg. The drum is designed to polish up to 50gms of silver: about five average rings.

The CE-marked fully-enclosed magnetic oscillator is rated at 230V 15W, so you can use a regular mains socket. It comes with a 1.8 metre cable, ending in a UK plug. Since the tumbler uses about as much power as a fridge bulb, the cost of using it is only a few pence a day.

The acrylic drum has a lift-off lid, and the polisher has rubber feet to stop it creeping across the worktop and falling off when you're not there.

Initially, the stainless steel pins will have sharp ends, so it's a good idea to run the polisher with some scrap silver for an hour or two to begin to round them off.
Although the drum is made of clear acrylic, the continual impact of so many tiny metal pieces will soon give the inside a matt finish: this is normal.

POLISHING PINS

The stainless steel shot, included in some of the rotary tumbler kits, is not just round but a selection of shapes, such as pins, planetoids, and spheres, designed to deal with the range of contours on jewellery.

Although the shot is 100% stainless steel, don't leave it lying around wet: either leave it immersed in the tumbler mix of water and cleaner, or rinse it and dry it carefully.

If you need to replace the shot, don't economise and buy plain or mixed steel: unless you're meticulous about cleaning and drying them every time you use them, they will soon rust, make a mess, and ruin your work.

When you open a new packet, do it over a bowl. The shot is surpringly agile and will easily escape, go on the floor, and roll everywhere. Either brush it up, or use a magnet: then wash it.

When you've finished, empty the pins into a cloth-lined sieve, rinse it thoroughly, and spread it on some cloth to dry. Don't accidentally flush away any pins as they will collect in the basin trap.

Initially, the stainless steel pins will have sharp ends, so it's a good idea to run the polisher with some scrap silver for an hour or two to begin to round them off.
Although the drum is made of clear acrylic, the continual impact of so many tiny metal pieces will soon give the inside a matt finish: this is normal.

Stainless steel pins are quite expensive, and heavy to post: extra pins can be included, post free, with your polisher. Don't buy plain steel pins: unless you're meticulous about cleaning and drying them every time you use them, they will soon rust and ruin your work.

Using the polisher is simple, so there's no manual. Quarter-fill the drum with water, the stainless steel pins, and your work. Add a very fine sprinkle of washing powder, put the lid on, and let it run for 20 minutes. Experiment with the running time until you get the desired finish.

Unlike a rotary tumbler, where the shot and the silver are continuously and randomly falling together, the magnetic polisher has four rotating magnets which drag the pins around so they impact on the silver. You'll notice that, apart from very small pieces, the silver, not being magnetic, may stay with the same side facing down, so will need turning over every ten minutes or so.

GONE IN A FLASH

The tumbler comes with a 2.0 metre cable, ending in a regular UK 230V plug. As the motor is only 15W, you can use any mains socket. The plug only needs a 3A fuse and must be earthed.

Since the tumbler uses about as much power as a fridge bulb, the cost of letting it run continuously is only a few pence a day.

As with all electrical equipment, don't get it wet and don't touch it with wet hands. Always unplug it when it's not in use or being serviced.

Always empty the drum away from the tumbler, to avoid spilling or losing anything. Every two weeks, unplug the tumbler and put a few drops of oil on any visible bearings. Leave the belt as loose as possible without it slipping.

The tumbler has rubber feet to stop it creeping. However, make sure it's on a stable flat surface, away from the edge.

Although wearing ties is not nearly as common as it was, be careful, if you lean forward, that your tie, or your hair, doesn't get caught round the roller.

Although tumblers and polishers are very robust and normally last for years, any service or repair used to need a return to Germany, Japan, or the US. The down-time was a serious setback for any small business, and the return shipping charges cost as much as a new tumbler. Kitiki tumblers and polishers are serviced here, in the UK.

Unless you deliver and collect your tumbler or polisher, it must be carefully protected for the journey: so it's a good idea to keep the original box and internal packing. If you don't have the original packing, find something that can be re-used for the return journey as we don't have any empty boxes.

Kitiki can't keep every part for every tumbler and polisher in stock all the time. Although we always order parts promptly, there's often a manufacturer's delay, a public holiday, a world-wide material shortage, a trainee delivery driver, traffic chaos, or some other complication.
I know waiting is distressing but, unless you're really competent and have tools and test equipment, don't try to repair electrical equipment at home.