Polishing and Finishing for Jewellers and Silversmiths E-Book

Stephen M Goldsmith

• Herausgeber: Crowood
• Kategorie: Lebensstil
• Sprache: Englisch

Veröffentlichungsjahr: 2019

Beschreibung

Polishing and finishing is a highly skilled specialist craft; a professional finish will transform a piece of jewellery or silver into a work of art. Written by a leading polisher, this practical book explains the traditional techniques and shares the secrets of this often-underrated craft. The book includes advice on setting up a workshop, tools and compounds; a guide to finishing methods (including satin finish and oxidising); step-by-step examples of polishing bangles, rings and cutlery, as well as finished photographs showcasing a range of exquisite work; tips on best practice for designers, and specific advice for polishing different surfaces and gems. It is an invaluable guide to the process of polishing and finishing - a highly skilled specialist craft- beautifully illustrated with 162 colour photographs showcasing a range of exquisite work.

Leseprobe

Polishing and FinishingFORJEWELLERS AND SILVERSMITHS

Stephen M Goldsmith

THE CROWOOD PRESS

First published in 2019 byThe Crowood Press LtdRamsbury, MarlboroughWiltshire SN8 2HR

www.crowood.com

This e-book first published in 2019

© Stephen M. Goldsmith 2019

All rights reserved. This e-book is copyright material and must not be copied, reproduced, transferred, distributed, leased, licensed or publicly performed or used in any way except as specifically permitted in writing by the publishers, as allowed under the terms and conditions under which it was purchased or as strictly permitted by applicable copyright law. Any unauthorised distribution or use of this text may be a direct infringement of the author’s and publisher’s rights, and those responsible may be liable in law accordingly.

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

ISBN 978 0 78500 524 4

Frontispiece:Waterlily Egg by Lina Siaudvytyte. Photograph by Stephen Mynhardt.

Acknowledgements

Thanks to Ian Baker, Alison Goldsmith, Theo Fennell, Rebecca Skeels and Andrew Willgress for their help with this book.

CONTENTS

1 THE JEWELLER’S POLISHING SHOP

2 TOOLS, EQUIPMENT AND MATERIALS

3 FINISHING METHODS

4 PREPARATION OF YOUR CREATION

5 POLISHING FOR SILVERSMITHS

6 ADVANCED METHODS

FURTHER INFORMATION

CHAPTER OPENING PHOTOGRAPH CREDITS

INDEX

CHAPTER ONE

THE JEWELLER’SPOLISHING SHOP

Polishing and finishing is an extremely antisocial pastime: noisy and dirty, and often partitioned off in a corner of a jeweller’s workshop. This chapter considers the main factors to consider when setting up a polishing workshop, as well as crucial health and safety aspects.

The set-up

Lighting, ventilation and extraction

Good lighting is essential: fix a movable strip light just above where you are working, at a maximum of 2 feet (70cm) above your head. This will aid you when polishing flat pieces.

Effective extraction is also necessary, as dust will inevitably fly all over the place. This dust is money, so keep track of it and save it in a heavy-duty bag for later. However you save the dust (known as ‘sweep’), it will pay you dividends in the future, not least in terms of your health – you won’t be polishing for years in a dusty environment. Also, the dust contains the valuable metal you have been polishing; there are various ways that a precious metals recycling company can remove it (see also ‘recycling’ below), and it’s a good idea to keep the metal sweep separate, especially platinum.

The bench

The bench around the machine is a must for a put-down area and also creates a barrier to stop you or others walking into a moving spindle. Make sure the bench gives you plenty of clearance to work around. A drop-down bench panel to the front or side, or an easily movable bench, comes in handy when you are polishing extremely large pieces.

Make sure the bench is flat with no areas to lose a stone. This costs time and money, so plan your area, filling any gaps with a silicone filler. The surface needs to be easy to clean, so stainless steel is a good option; the area will get dirty no matter what, so make a plan to keep on top of this.

Bench height is important for both silversmiths and jewellery polishers. Silver polishers stand, as it easier to polish bigger items, so the bench is at waist level. Jewellery polishers sit down and it is more comfortable if your feet can touch the ground and your elbows can rest on the bench. It is possible to set your bench for standing and sitting according to the item you are polishing with an adjustable seat. It is the spindle height that needs to have clearance above the bench: too low and you will be limited to the size of piece you can polish without touching the bench.

HAND CARE

Always use a barrier cream and moisturize your hands regularly. Protect them with chemical-resistant rubber gloves when using harsh acids and chemicals; acetone and paint stripper are likely to melt normal household rubber gloves. Take particular care with Platinol, which will stain your hands and fingernails: once contaminated it is impossible to remove a stain, although it will grow out eventually. Avoid using gloves when polishing, especially rubber or latex. If something goes wrong, the spindle will drag the rubber and take your fingers with it.

APRON, MASK AND GOGGLES

Always have an apron on hand, and keep old aprons for reclamation. Tie up long hair, and remove any rings, bangles or bracelets.

Always wear a mask and goggles.

Head shields are an option for protecting the face, especially when using a frosting brush. (Photo: The School of Jewellery, Ireland, featuring Clare O’Connor & Jill O’Malley.)

Storage

Tools and materials must be stored carefully and systematically, such as a set of drawers with finishing tools at the top, working down the various abrasive stages towards the bottom.

As part of your workshop you may also find a pegboard on the wall useful for keeping your tools separate.

Cleaning

A partitioned wet area to clean your work is essential, with running water and a very large ultrasonic or steam cleaner at the very least. Also in this area is the plating equipment; plating units come in various sizes, as described in the next chapter, but usually include three pots, one containing a caustic soda cleaner and the others containing whatever you are plating with, such as gold or rhodium.

Recycling

In some instances the reduction in the metal between a casting and a finished piece can range from 10 to 25 per cent. It is therefore essential to make sure you capture all the precious metal from the start to the finish of your jewellery manufacturing process.

If possible, set up your polishing shop so you can wash your workwear in-house and use sticky rubber mats on all exits to grab the sweep as it tries to leave the workshop. A reclamation mat is designed for use as a floor mat in polishing areas. The sticky surface captures and holds on to your precious metal dust without adhesive transfer to your footwear.

Precious metal settlement tank. (Pressman Mastermelt Ltd.)

A precious metal settlement tank, simply connected between the sink and the waste pipe, will collect the majority of your precious metal residues normally lost during hand washing or when rinsing work. It is a worthwhile investment, as it simply pays for itself.

Inspect your dust collectors and replace filters on a regular basis. Use wet wipes to wipe down all surfaces and recycle those too.

Have a scheduled sweep and vacuum time with dedicated equipment and storage for vac bags, wipes and perhaps other items being held for future refining. Keep a sweeps barrel on hand for all reclamation items, such as dust, tools, tissues, cotton wool and wipes. Some items are often replaced that should be processed, such as emery sticks, brushes and mops.

CHAPTER TWO

TOOLS, EQUIPMENTAND MATERIALS

Polishing machines

The heart of the polishing workshop is the buffing machine; these come in various shapes and sizes for jewellers. As they are not generally designed by polishers it is helpful to know what your needs will be before investing in one.

The machines may be bench-mounted or free-standing. The bench-mounted models need to be bolted to a very heavy-duty bench specifically made to hold the weight with no vibration. The free-standing machine is bolted to a concrete floor, which is the better option.

It is vital that you have an emergency stop button fitted to this machine, which comes in the form of a foot press. As in all machine shops an emergency button on the wall for easy access is essential, this will stop the electric instantly but note the spindle will still be going around. Some machines are fitted with an automatic spindle break too, which is a useful extra to look out for.

Power is measured in horsepower, starting at ¼hp and working up to 1hp. The lower the horsepower, the more easily the machine will stop. A machine with ½hp to 1hp polishes quickly and does not slow down when polishing a bigger object. The run time is better too, as polishing machines get hot and need a break after a couple of hours.

All polishing machines run at just under 3,000rpm – any quicker will not polish – and some are dual speed with an option of 1,500rpm. The slower speed is great for platinum solder seams.

A single- or double-spindle single-phase 1.5–2hp polishing machine is usually bench-mounted. A much more industrial set-up will require at least a 2hp double-spindle 3-phase polishing machine. The most economical way to run a 3-phase machine is via a static converter 1.5hp/1.1kW HT – single to 3-phase 240V to 415V rather than the costly alternative of installing 3-phase in your workshop. It is very easy to install: your machine plugs directly into the converter via an industrial five-pin plug and then the output goes directly into a UK plug socket. For simplicity, use one converter per machine.

The quick fix for an instant polishing shop: a free-standing set-up with extraction, lights, storage and variable speed. (Photo: H.S. Walsh & Sons Ltd.)

Polishing machine with extraction and dual motors, which saves stopping the other polisher. (Photo: Curteis Ltd.)

Machines with a higher horsepower are useful for much bigger creations, such as very large trophies, etc.

There are bench-mounted polishing machines available that come complete with extraction and lighting. Choose single or double spindles according to the space available.

There is also the ‘do-it-yourself’ polishing machine option: a converted grinder. Choose one with long spindles in all options, the longer the better. You will need to bolt the machine down with a foam pad to stop the vibration, set on a sturdy bench with the machine on top. Then you can buy ready made hoods with the facility to fit an antistatic extraction tube to the back or the bench. The hood can be moved out of the way if needed – most ready made machines have this option – but if you remove the hood you must wear a mask and goggles.

Converted grinder option with no extraction. Note the longer spindles.

Spindles

Detachable tapered spindles are a must. They come in various lengths and thicknesses. The shorter spindle is generally suitable for jewellery and watches, and the longer ones give you more clearance. The thick ones are used on more industrial polishing lathes used by silversmiths, polishers, or in the general trade. There is also an adapter (called a ‘false end’), which screws onto the original spindle. This enables a thinner spindle to be used to get into tighter areas and gives you a better angle.

This spindle has letter R (right) to aid in assembly. If you screw it onto the wrong side your mop will drop off.

The spindle pushes on and is tightened with an Allen key.

Short single spindle with extraction and light.

Note the bar for easy removal of the spindle. Push down to remove.

Use the correct machine for the job in hand; if space is too tight there is no clearance.

Note the clearance: a bigger mop is needed to clear the spindle and tilt to clear the bench. Build the bench lower or include a drop-down bench within your design.

Removing the mop. Turn anticlockwise.

SPINDLE SAFETY

Never leave a bare spindle unattended. A revolving 3,000rpm sharp spindle is potentially lethal.

Ultrasonic and steam cleaners