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The Kitiki Rotary Tumbler Kit 2

THE DRUMS

Plastic drum lids need to stand in hot water to make them easier to push on. To free the lids, the whole drum needs to stand in hot water. There's a slight risk that, as you pull the lid off, you'll spill your work, shot or grit, and soapy water.

It's very important not to try to force the lid on, unless it's been in hot water: it may crack. When the lids are firmly on, give them a gentle end-to-end squeeze to expell any excess air, otherwise the warmth of tumbling will expand the air and water may leak out.

Kits 1 and 2 have a smaller simpler base unit than kits 3 and 4. The two plastic roller-brackets have a central projecting tab to stop the barrel creeping along the rollers and falling off. The lid on the rubber barrel has a slight taper: if it jumps slightly makes sure the metal lid faces the pulley wheel.


If you want to do shot-tumbling and grit-tumbling, you should use two barrels: marked so that you don't mixed them up. One stray grit particle caught in the drum will scratch your shot-tumbled work: the scratches are quite hard to remove.


A silicon lubricant is used during the manufacture of rubber drums. Before use, clean the drum with a scouring pad and some washing-up liquid.

STAINLESS STEEL SHOT

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, always 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: it'll soon rust, make a mess, and ruin your work.

When you open a new packet, always do it over a bowl. The shot is surpringly agile and will easily escape, go on the floor, and roll everywhere. If you do spill it, 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 and lead to a blockage.

BARRELLING COMPOUND

Barrelling compound, sometimes called gallay compound, is a special soap used to keep the barrel and shot clean, lubricate the tumbling, help the polishing action, and minimise rust. The drum needs about a level teaspoonful.

GRITS

Grit is the generic name for the abrasive particles used to grind and polish. Generally, it's graded silicon carbide: an angular, hard, sharp, material which fractures into smaller angular particles, making it an effective abrasive.

Grit sizes are confusing, for example: 400 grit particles are not twice the size or half the size of 200 grit particles. You'll soon learn 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.

CERIUM OXIDE

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.

ELECTRICAL SAFETY

The tumblers come with a 1.8 metre cable ending in a UK 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 less power than a fridge bulb, the cost of using it is about a penny 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.

MECHANICAL SAFETY

The neoprene drive belt should be as loose as possible, providing it doesn't slip. If it's too tight, the motor will strain and overheat. It's supplied correctly set, but the belt tension can be adjusted using the three motor fixings.

Once a week, apply a drop of motor-grade oil to the four places where the drum rollers pass through the bearings. Once a month, apply a drop to the motor bearing.

The tumbler body has plastic edges to stop it creeping across the worktop. 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.

USING TUMBLERS FOR ART CLAY AND JEWELLERY

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


Before starting, wash the drum thoroughly using a soft brush and some mild detergent, and rinse it clean. This is particularly important as one left-over particle of grit, tumbling for several hours, will leave scratches that will be very 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 about a level teaspoonful of barrelling compound, and then enough cold water to cover everything. The tumbling action won't work if the barrel is full, so never fill it more than about 40%.
Fit the lid, put the drum on the rollers, and start the tumbler. Try two hours, and then longer if you think that the finish can still be improved. More water gives a gentler action.

Empty the contents into a cloth-lined sieve over a bowl to save the liquid, rinse your work and the shot under the tap, and remove them carefully. Wash your work, 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 will need replacing.

Interestingly, one manufacturer recommends 500gms of shot for a 1400gm drum. As the supplied drum is 700gm, the implication is that 250gms will do. Nearly everyone using tumblers uses more: at least 500gms.

As with any process, different materials need different abrasives tumbled for different times. It's important to research the subject and experiment with the variables until you get the desired finish. There's no simple formula for getting instant results.

USING TUMBLERS FOR STONES AND GLASS

Anyone who has found shiny fragments of glass, beautifully rounded pebbles, or highly polished shells on a beach, has seen how continual fine random abrasion can shape and polish even the roughest surfaces. These beach treasures have probably been in the sea for years.

Although tumblers provide continuous and distributed abrasion rather than intermittent and scattered abrasion, and the grits are very hard and very sharp, it still takes days to smooth off irregular stones, minerals, or pieces of glass.


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 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. As with so many things, try it and see.

Select stones which are of similar hardness. Fill the 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.


Gradually, the grit will lose its sharp edges and will need to be replaced. If you know that you'll be doing a lot of stone or glass work, it would be better to buy a second grit pack.

SERVICE AND REPAIR

Although tumblers 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 are serviced here, in the UK.


Unless you deliver and collect your tumbler, 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.

Cherry Heaven can't keep every part for every piece of equipment in stock all the time. Although we always order promptly, there's often a manufacturer's delay, a public holiday, a trainee delivery driver, traffic chaos, a world-wide material shortage, 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 tumblers at home.