Increase Your Sales

 I came across this just now and think it might have wider relevance. As Patricia says, make a 10-minute space in your day for some inspiration on selling.

From The Design Trust

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Do you want to get more sales, clients or commissions? Of course you do! Grab yourself a nice drink or lunch for this 'long read'. Today I want to take you through these 6 questions to help you get more sales, orders & commissions. See it as a short, unexpected 10 minutes mini-marketing course. Full of ideas & inspiration. For free in your inbox. Enjoy! And feel free to pass it on to other creatives too. ​ Q1: What are you *really* selling? You might think that the answer to this question is: “My jewellery” or “My workshops” or ‘My illustrations & prints”. But … people who buy creative products and services often buy so much more than ‘just a product’! They buy because they want something really original and unique. A special gift for a special friend or occasion. To celebrate. To treat themselves! Start to think about your creative products much more in terms of a 'memory' that they are buying, or a gift that reminds them of 'friendship' or 'the freedom of the sea'. Focus on the feeling that they want to get when they are wearing your colourful necklace or give a beautiful handmade jug with hand-picked wild flowers to a dear friend who is going through hard times. And even if you are selling to shops and galleries think about what you are selling to them. They want to create wonderful displays of emerging or local creatives. They want to show gorgeous hanging flower pots for the summer and to be 'on trend' and share on their Instagram feed. They want to have 'wow pieces' for their window display to lure visitors back into their shop once again. And when you are selling your creative products & services you are also selling a little bit of you of course! That doesn't mean we want to know all your secrets or what you had for breakfast. But your clients want to connect with your creative lifestyle, they want to know how your environment looks like and how that inspires you, your values from sustainable gold, or mindfulness, to Black Lives Matter and how that connects with them as 21st century human beings and consumers. Especially if they love buying from small independents and find it important to spend with small creatives like you! Take action: Brainstorm around what YOU are really selling. Go beyond the 'what' of your products and services, and think about the emotions or feelings your ideal clients have … not just when they are looking to buy, but also when they have bought your work, when they use it or give it to somebody else. WHY do you create the work you do? Emphasis these stories and occasions much more in your social media, your images, your product descriptions and your emails to really connect with the emotional side of buying, owning and loving creative products & services. ​ Q2: Have you got a plan? Did you set a financial goal at the start of 2022? Do you know how many sales you want or need this year? Online, at events, from stockists? We are big fans of financial goals here at The Design Trust! Why? Because without a goal or destination that you are aiming for you will just be running around like a headless chicken or just ‘hoping’ that things will happen and that the universe will listen to you. I personally don’t believe in that working out very well … Plus … if you don’t have a financial goal for your different income streams then you can’t really create a proper marketing plan either! You will need to know which products or services you want to focus on for sales, who your clients are and how much you will charge. Selling £15,- products on Etsy needs a very different marketing approach than selling £150 necklaces online or at an event. Of course, this year is very unpredictable. You might think that there is no point in creating a plan as it will have to change before you have even started. You might have had to change your financial goal for 2022 (we have!). That’s actually perfectly normal! And at least you are being realistic about what's happening in the world right now. You are being pro-active. And you will be more in control when you know what you are aiming for. ​Next Monday morning 4 July I will be hosting a practical 3-hour Plan The Rest of 2022 online workshop where you will be setting your own smart + juicy goals for 2022. ​ ·         Juicy goals + do-able actions for yourself and how to make sure you are in the best mental & physical place to create and work. ·         Juicy goals + do-able actions for your finances, your different income stream goals, to keep an eye on your costs. ·         Juicy goals + do-able actions for your marketing – with my expert tips on exactly what marketing activities to do to get more online sales, event sales, wholesale orders this autumn. ·         Juicy goals + do-able actions for your creative production. To stop making without thinking about who your ideal clients are (see below!), your actual costs + what you can charge. ​If you want to be less overwhelmed and back in charge then join me for this practical, thought-provoking planning workshop next Monday (the first Monday morning of the 2nd half of 2022!). Q3: Who are your ideal clients? And do you know why, when & where they buy? Do you really know who your dream clients are? Why they buy your creative products? When they buy? What’s important to them? What stops them from buying from you? Many creatives find marketing really difficult and it’s often because they don’t really know who their dream clients are. They try to sell to anybody, but then fail as it doesn’t appeal to anybody either! Many creatives rarely think about their clients when producing new work. Some creatives are even scared of their clients! Getting to know your ideal clients at a deeper psychological level can really help you to create products that people love to buy. It can help you to get more confident to create more innovative, unique and more well paid work too. It will help you to connect with the right people who have similar values and interests as you, boosting your inspiration & confidence, and then selling, marketing and talking to them will be so much easier! ​In exactly two weeks’ time on Monday 11 July from 10am – 2pm (UK) I am hosting a 4-hour practical workshop around Dream Clients – to help you to identify, get to know, approach and wow your ideal clients. Step-by-step you will find out and get a lot more confident to reach out to them and get sales and orders. ​ Q4: Are you just selling or actually building relationships? If you don’t really know how marketing works then it often feels like you are ‘pushing’ people to target them to become your client. And especially when you start to get a bit desperate for sales then often it’s very obvious that you are selling the hard way! Marketing & selling should NOT be pushy! At The Design Trust we have a marketing mantra: “People only buy from people they know, like & trust”. Unless people know what you can do for them (see Question 1!) and remember your name (so standing out from the crowd is important!) you will unlikely get any sales. They need to really fall in love with you these days to get their credit card out. And they need to trust that you can deliver. Marketing that works (=to get sales) is based on two principles: 1. Focus on a niche: What are you good at and who is interested in that? Don’t sell to everybody but really focus and get to know your ideal clients. 2. Build relationships with your clients, especially if you are selling unique or less frequently bought purchases, high end work, or services like craft & design commissions or workshops. People need to think about their purchase, and that's part of the natural process of buying from you. Stay in touch and be helpful. Marketing & selling is about pulling in the right people that love what you do & what you stand for! Listening to them, taking care of them, creating value for them in their lives. Get into action: How can you build your profile, credibility & trust with your ideal clients? How can you reach out to them and remind them what you really do? (See Question 1 again!) How can your marketing become more ‘educating them’ around your values or creative process? And especially if you are selling to other businesses, galleries or shops how can you be helpful to them right now? How can you promote them and highlight them on your website, emails or social media? Could you offer to do a demonstration or talk? Have you talked to them about the new work you are developing and have they got the best images to promote you? Q5: Do you encourage clients to spend more? Offer commissions & pre-order! This might sound counter-intuitive but the creatives that are struggling the most right now are those selling work between £100 - £1,000. Why? Because up to £100 is a gift. Either for themselves, or for others. And it’s often a quick purchase that they don’t need to think about too much. There will always be birthdays, weddings or other special occasions that need lovely, unique creative products! Above £1,000 is the territory of commissions and higher end unique work. These are often very special and very personal purchases, for special occasions like wedding anniversaries, house extensions and even memorials. And many collectors will keep collecting! (This part of the market has not been impacted that much by the cost-of-living crises as most of us …) When you are trying to sell work between £100 - £1,000 then often you are both too expensive (for people looking for a gift) and too cheap (for people who want something really unique) at the same time! We are big fans of using more pre-order options and don’t really understand that not more creatives are using this opportunity to promote new work to their clients who then can purchase it for a selected period only at a very special price. The big benefit of pre-ordering is that you get a far better idea of how much stock to create, which designs or colours will be more popular and you will be paid upfront! Very useful indeed for your cashflow and to avoid loads of unsold stock later in the year. We are even bigger fans of commissions! These are creatively, financially and personally great opportunities for creatives to create amazing and really unique works of art, that push your creative skills, raise your profile, and really are very meaningful for your clients too. Commissions really can be amazing for both creatives and their clients. But … we also know that many creatives do not manage their commissions or their clients very well, and have trouble setting boundaries, do not charge properly for their time and expertise, and find it difficult to promote themselves and their commissions. We recently did some research around commissions and realised that there is very little advice around this important topic and income stream. So, we created this brand-new online course Creative Commissions to help creatives manage commissions professionally (with loads of templates!), price your commissions properly and promote yourself too. ​Creative Commissions is a 2 x half day online course on 14 – 15 July PLUS we have invited 3 creatives and experts for 3 x 1-hour interviews too so you can learn from their expertise and as them questions too. Can’t make this course live? No problem! All the sessions are recorded and you will have access till the end of 2022 to the course. Q6: Do you encourage repeat business? And finally … something that’s often overlooked by creatives: your existing or previous clients! Don’t take them for granted. They already know you, like you, and trust you! So it's often much easier to sell to them. Get into action: Have you heard about the Pareto principle or the 20/80 effect? It turns out that about 20% of your sales will come from 80% of your clients! Do you know who your top clients are? Check your bookkeeping system and see who those top clients are. Can you get to know them better? Do you know where they live, what gender they are, how much they spend and how often they return? If they bought online or at a specific event? Even simple factual data like that can help you to get to know them, and to connect with them better. Could you let them know that you are working on some new work that’s related to what they purchased before? Hint: Tell them they are the first to know about this new collection you are launching in September! Have you got an event coming up near them that they might like to get an invite to? What else would this client like to buy? Could you give them special treatment to show that you appreciate their custom? Can you create exclusive videos showing your creative process, could they get VIP invites for your Summer Sale, or can you give them free postage & packaging next time they buy? Making your clients less ‘strangers’ and more human beings is really the only way to build your business, your ideas, your creativity and your confidence. ​ And that’s it! The end of your unexpected mini-marketing course! 6 questions to help you get more sales this summer. I hope you found it useful and that you got inspiration to take some action too. And of course we would love to help you with getting more sales & getting more organised in one of our 3 Summer courses. Looking forward to seeing you. Patricia van den Akker The Design Trust – the online business school for designers, makers & other creative professionals ​www.thedesigntrust.co.uk @TheDesignTrust​ ​ ​

Applying for Craft Fairs

The Application

Read the application guidelines

Read them carefully.  Make sure you note the exact requirements given in the guideline notes.  Most craft, design and trade events have very similar requirements - name, contact, background, CV, artist statement and images.

But to complete the information appropriately you need to do exactly as they request.  Complete all the questions. Send only the requested number of images.  Make sure you have sent them in the exact format they ask for.

You need to read between the lines of the application guidelines to understand best what the event is looking for.  They may be looking for production work, designer or lifestyle items, etc.  Reading between the lines will give you an indication of how to steer your application to attract the selectors attention.   This will help you present the written parts of your application in the light of the organiser’s objectives.  This will apply particularly to the CV.  It is here that your story of what, how and why you make glass will distinguish you from other applicants. Importantly, it will also apply to the selection of your images.  If your images fit the objectives of the event, you are more likely to be selected.

Show your best pictures

The most important part of your application is the images you send.  This, more than anything else, will count in your favour during the selection.  Of course, the written material still counts, but the first element is the images.

They need to be of professional standard, ideally taken by a professional photographer. When you are selected, these images will be used in promotional materials, for the press and for the exhibition catalogue. So, great photographs are more likely to get your work into the press for the event.  Conversely, if the images are not of press quality, they are unlikely to be selected.

The images should represent in detail the things you will be showing at the event.  They need to show an overview, with some variety, of what you do.  They should show your skills and quality of production.  Some idea of scale is essential.  This is where props can help.  You can use lifestyle settings which allows more items to be shown, but make sure your work is the focus of the photograph. 

Often it is best to photograph each work as a single item on a white background.  Well-lit studio photographs work well, but daylight settings on an overcast day can provide really good images with indirect light, as any harsh shadows are eliminated. 

The images need to be labelled – often in the file name – with your business name, title and short description. 

When preparing your application and images, make sure you update the website, because the selectors will be looking there for more information and images, especially of any previous shows you have been to and show there.  The freshness of the site’s appearance will have an influence on your selection.

Return your application on time

This is obvious, but not always done.  Take note of the application deadlines, and make notes in your diary as to when things need to be done to get the application to the organisers on time, or even early.

If the event is not a selective one, you need to get in early as applications are often reviewed as they come.  Juried events will have all the applications looked at on the same day, but give the organisers enough time to get the images loaded and co-ordinated with your application.  Remember that organisers get many applications, so you need to make it easy for them to like your work.

Get feedback

If you are not selected, you can review your application to see what you might do better next time.  The rejection letter may give you some information, if it is not a generic one.  It may be that there were just too many applicants, or too many with glass as their medium.  Did your work fit with the ethos of the event – e.g. traditional vs contemporary.

You can contact the organisers - politely – indicating theirs is a show you really want to get into because of its quality or other element that is complimentary to the event.  Your questions should be polite and ask for feedback on specific things, so it is easy for them to respond.  Many of these questions will be centred around what you could do differently to have a better chance of selection next time.

It is just possible a polite professional approach to getting feedback may take you off a waiting list and into the event. In any case, visit the show, if you can, to see how it looks and feels.

https askharriete.typepad.comask_harriete201212responsibilities-of-craft-show-organizers.html

The Organisers’ Views

Research

Show the event has been researched by indicating how your glass work will fit with the organiser’s objectives.  How does your quality of work fit with the other exhibitors?  Give evidence of stands and participation at other shows, especially on your website and social media.

Application

It is most important that the application guidelines have been read and adhered to.  You should include relevant personal information on what inspires you, where you work, the materials and techniques you employ – in short, your story.

Images

Present images showing a confident, original group of work rather than showing all your variety.  The pictures must be in focus, well lit, with clean backgrounds and with detail shots only were necessary.  Many organisers get four or more applications for each available stand, so the photography is essential to show the potential of your glass.

Have good, up to date images of current work on your up to date and professional website and social media.  Often your website will be considered for more information, especially their previous stands at other events.  It is often good to see images of previous stands at previous shows.

Review

Don’t take any rejection personally. Don’t give up.  Review why you were not successful – right fit to the event? Too many of your medium/style applied? Does your glass stand out from others? Perhaps you need more confidence in your work.

Finally

“Fit the criteria of quality, innovation, skill and dedication” [in your application]. Samme Charlesworth, Director of Breeze Art and Makers Fair in Cornwall.

Selectors Views

The administration

The selectors and the organisers work together to create a focused event with originality and quality of work with a combination of established and emerging makers.  They also want diversity of media and styles with a variety of price.  Applications which have not met the application guidelines will have been eliminated by the organisers before the selection process begins. 

Often the organiser will give the selectors the number of applications and the number of stands available, with an indication of how many per category.  Then the selection begins.  Sometimes a quick pass through the images will be the first stage, followed by a slower showing at which the selectors vote for inclusion, exclusion or possible (waiting list).  The waiting list (of around 20%) provides the organiser with some flexibility to fill gaps where selected people do not take up their place, review the balance between established and emerging makers, the balance of media represented, etc.

This administrative process shows how important images are in the selection process.  Only the people on the waiting list are ever likely to have the other parts of their application viewed by the selectors.  The text you provide in the application gets you to the selection or eliminates you at the first stage.

The Selection

The selectors need to be able to distinguish what the images show.  If you show only detail, it will be difficult to determine what it or its function is. Too many other items in the image make it difficult to determine which are the items for the show. Dark images do not show the glass at it best. Extreme contrast makes for uncomfortable viewing. Material of composition should be apparent in the images. Whether the glass is production or handmade needs to be obvious.  A combination of these failings will be likely to get your work rejected.

Your images should show a coherent group of work. Diverse styles and materials make it difficult for selectors to see a style or brand. A unity of theme for the group of images is needed.

Technically good images are essential.  Focus is absolutely essential.  Any camera shake or unfocused images will not be viewed favourably. Use the same level of resolution and format for all your images so that all you work appears on the same scale to enable the selectors to judge the size of the pieces in the images.

Images must be professional in appearance.  If your work is selected, the images may be used in promotion and  the catalogue.  So, it must be of a quality for reproduction in the news and design press. Busy backgrounds are distracting and not normally suitable for the press.  Lifestyle images must be clearly focused on the glass.  The surroundings cannot intrude on or dominate the piece of glass being shown.

Using models to display your work requires professional photographer to be effective.  Amateur photographs of pieces on models will not get selected.

Show your work at its best.  Close ups will show quality but only a small proportion. Present a few items to focus attention on the group of items you intend to present at the show.

One of the images you present to the selectors might be of you working on one of the glass pieces, or your packaging or branding in the context of a stand.

Emerging makers are more likely to have their website and additional information looked at.  So, it is vitally important that these are up to date with current work, and older work put into a subordinate section.

Glass 101: Fused Silica vs. Quartz

 

Glass 101: Fused Silica vs. Quartz

Posted Krista Grayson on Jul 27, 2021

Quartz, fused quartz, quartz glass, silica, fused silica… the list of terms used to describe various silica-based materials is long, confusing, and often misunderstood. In this article, we take a close look at the unique properties of quartz and fused silica (and a few related materials), and clear up the confusion surrounding these terms.

Quartz vs. Silica

The first important thing to know about quartz and fused silica is that they both primarily consist of the same ingredient: silica, also known as silicon dioxide. Silica has the chemical formula SiO2 and is the primary constituent of most types of glass. The main form in which silica is found in nature is the mineral quartz: a hard, transparent crystalline material that makes up an appreciable fraction of the Earth’s crust. While quartz primarily consists of silica, it also contains naturally occurring impurities in various proportions depending on its geological origin.

So, silica is a specific chemical compound, silicon dioxide, with the chemical formula SiO2. On the other hand, quartz is a naturally occurring crystalline mineral, which consists primarily of silica but contains some impurities.

Crystalline and Amorphous Solids

To fully understand the differences between different silica-based materials, we first need to review the fundamental differences between crystalline solids and amorphous solids.

The distinction comes down to how atoms are arranged inside the solids. In a crystalline solid, the constituent atoms are arranged in regular, repeating patterns known as crystal lattices. Quartz is an example of a crystalline silica-based material: silicon and oxygen atoms are arranged in a well-defined ordered structure.

However, in an amorphous solid, the atoms have no long-range order. The seemingly random arrangement of molecules in an amorphous solid resembles that of a liquid, except that they are fixed in place and don’t move around. Most materials that we think of as “glass” are amorphous solids: in fact, any material with an amorphous atomic structure can be described as “glassy”.  

Whether atoms are arranged in an orderly manner or oriented randomly can profoundly influence a material’s characteristics. One of the most striking examples is the glass transition effect exhibited by amorphous solids. Outside the world of silica or other oxide-based materials, disordered “glassy” metals are often used for their unusual mechanical characteristics compared to conventional metals.1

Silica-based materials – like quartz – can be characterized both in terms of their chemical composition and whether they are crystalline or amorphous.

Defining Silica-Based Materials

Now that we’ve reviewed some important fundamentals, we can define the differences between quartz, fused silica, and other silica-based materials.

Quartz

As mentioned previously, quartz is the main form in which silica occurs in nature. Quartz is a crystalline solid; so, while it can resemble glass both in terms of its appearance and its chemical makeup, it has very distinct properties from glass.

Industrial applications of quartz (that is, the crystalline mineral) are limited, but include quartz crystal oscillators in electronic systems – most familiarly in wristwatches.

Perhaps confusingly, “synthetic quartz” can be manufactured for industrial quartz applications. This would perhaps be better referred to as crystalline silica, but is often referred to simply as “quartz.”

Fused Silica and Fused Quartz

Here, the word “fused” refers to a processing step: fused silica is nominally pure silica that has been melted and cooled to form a glassy, amorphous solid. Fused silica resembles other glasses in many ways; but it does not contain any additives. Fused silica is a specialty material with a number of high-performance applications.

The terms “fused silica” and “fused quartz” are often used interchangeably. More accurately, “fused quartz” refers to an amorphous solid formed by melting naturally-occurring quartz. So, while fused silica is ostensibly pure SiO2, fused quartz contains impurities depending on the quartz that was used.

Silica Glass and Quartz Glass

These terms are typically used in a more generic sense, and can usually be considered interchangeable. Both of these terms could refer either to fused silica or fused quartz.

Applications of Fused Silica

While fused silica is chemically similar to quartz, its amorphous structure gives it a number of distinct and highly desirable thermal, mechanical and electrical properties.

Glasses commonly contain additives such as alkali, alkaline earth, or other oxides to lower the glass processing (melting) temperature and to improve chemical and physical properties – but fused silica is very pure. Consequently, it has higher working temperatures but offers different characteristics from other glasses.

Fused silica has a very low coefficient of thermal expansion, meaning it does not expand or contract much when heated or cooled. As a result, fused silica is highly resistant to thermal shock and can withstand very rapid heating or cooling without cracking. The thermal characteristics of fused silica make it highly valuable for high-temperature industrial components such as crucibles, trays, and boats for steelmaking and glass manufacture.2

Fused silica is transparent to a very wide spectrum of light, extending from deep ultraviolet to far-infrared. This makes it a key component in optical fibers, as well as in a range of lenses, mirrors, and other UV- or IR-transmitting optics.3,4

Fused silica is also extremely chemically inert and resistant to most acids (with the notable exception of hydrofluoric acid). This chemical inertness lends fused silica to biomedical applications, often taking the form of porous silica.

The combination of thermal stability, transparency, and strength makes fused silica a strong candidate for new and developing applications such as photolithography substrates, etched microwave circuits, and as a protective layer in semiconductor devices.

Custom Glass Solutions from Mo-Sci

Mo-Sci develops and manufactures a range of high-performance glasses for technical applications. To find out more about our fused silica and porous silica products, or to discuss a custom glass application, get in touch with a member of our team today.

References and Further Reading

1. Glassy metal set to rival steel : Nature News. https://www.nature.com/news/2011/110109/full/news.2011.4.html.
2. Vert, T. Refractory Material Selection for Steelmaking. (John Wiley & Sons, 2016).
3. Khalaf, A. L., Shabaneh, A. A. A. & Yaacob, M. H. Carbon Nanotubes and Graphene Oxide Applications in Optochemical Sensors. in Synthesis, Technology and Applications of Carbon Nanomaterials 223–246 (Elsevier, 2019). doi:10.1016/B978-0-12-815757-2.00010-3.
4. Wang, S., Zhou, C., Zhang, Y. & Ru, H. Deep-etched high-density fused-silica transmission gratings with high efficiency at a wavelength of 1550 nm. Appl. Opt. 45, 2567 (2006).

Ramp and Anneal Rates for Tack Fusing

Tack fusing is more difficult than most realise.  Many failures – usually breakages – occur because the complexity of tack fusing is not fully acknowledged.

Ramp Rate 

Calculations

One of the effects is the slower rate of advance that needs to be used.  The rate of advance needs to be slowed to that applicable to 1.5 to 2.5 times the actual total thickness of the assembled piece. 

Reasons

The reason for this firing for apparently excess thickness is the shading effect of the overlying pieces upon the glass below.  Glass is affected by radiated heat, whether the heat comes from above or the sides.  The parts of the base glass that have glass on top cannot receive the radiated heat.  This means the shaded base glass needs time for the heat to be conducted through the overlying glass to it. 

Beginning of heat input

Progress of heat input showing some parts of the base are compeletly heated while others are not

Glass is a good insulator, resisting any heat transmission through overlying glass. Slowing the rate of advance allows the convection of heat to the lower levels to be adequate to avoid heat stress.  The reason for the 1.5 to 2 factors is that experience has shown a simple applied arrangement will be safe with a factor of 1.5 as the calculated thickness.  If you have stacks or lots of difference in thicknesses, you need a slower rate to allow for the conduction of heat.  This is where the 2 times actual thickness factor is useful.

Finding the Ramp Rate

The information on the rate of advance for evenly thick pieces of 6mm to 9mm is widely available.  Determining the rate of advance for thicker items is more obscure.  You can get some guidance from the manufacturers’ websites.  But where the guidance is for thinner pieces or it is unclear, you need to find another reliable source. 

One very reliable source is the Bullseye annealing chart for thick slabs.    Yes, this chart tells you about the annealing of thick items, not about the ramp rate to the working temperature.  But you can infer the initial rate of advance from the final cooling rate.  The principle is that the glass can survive the indicated cooling, so it should also survive that rate of advance from cold to working temperature.

This means that a set up of a 6mm base with two layers of glass pieces on top distributed around the base, is a total of 12mm.  This should be fired as though 18mm (1.5 times actual) or up to 30mm (2.5 times actual).  In the first case the chart indicates the final cool rate is 150°C per hour.  This can be used as the initial rate of advance to at least 540°C (above the annealing range).  If you choose to use the 2.5 times factor, the initial rate will be 65°C per hour.

This approach gives you a reasonable degree of certainty about how fast you can fire your glass from cold.  Note that you still need to have a conservative bubble squeeze segment in your schedule, especially if the lay up includes areas where air might be trapped.

Annealing rates

Annealing times and rates are normally dependent on the thickness of the fired glass.  But published annealing rates are based on both even thickness across the piece and on cooling from two sides – i.e., not on the floor of the kiln.

Calculating for even thickness

If you have taken your stacked piece to a full fuse, you can anneal for the final thickness.  I would be a little more cautious with a contour fuse and anneal as though it were three to six millimetres thicker than when completely flat because you cannot be certain that the piece is evenly flat unless you obeserve.

Calculating for tack fused

If, however, you are firing to a tack fuse you need to look to schedules for thicker pieces.

Reasons

Glass remains an insulator as it cools.  As glass cools, it must conduct the heat through the thick parts at the same rate as through the thinner parts to avoid inducing stress.  Remember the principle of annealing is to keep all the glass with 5°C or less difference in temperature.  The thinner glass gives its heat up quicker than the thick.  This will induce stress and it can be enough to break the glass in the kiln or, more usually, some long time after the glass is cool.  This means you need to control the cooling to a rate that would be suitable for thicker glass. 

At the beginning of the cool the heat loss is from the surface and to a lesser extent through the shelf.

Further heat loss shows the exposed base layer is giving up its heat throughout, although other areas are only beginning to cool.  It will take some time for the three layer stack to cool.  The uneven cooling leads to the introduction of stress.

Determining the rate

The annealing soak length and the rate of the annealing cool are directly related to the thickness calculated for your piece.  You have already chosen a calculated thickness for the rate of advance to avoid breaking the glass.  Use the rates given in the chart for that thickness for your soak and anneal cool.  Any annealing with a shorter soak and a faster cool risks inducing stress and possible breakage.

Rates of advance and annealing are intimately connected.  A tack fused piece must be annealed as though it were 1.5 and up to 2.5 times the actual total thickness.  Annealing of tack fused pieces cannot be skimped.

Further information is available in the ebook Low Temperature Kiln Forming.

Using Glass for Radiation Shielding

Using Glass for Radiation Shielding

Posted Krista Grayson on Dec 3, 2020

Certain types of glass offer excellent shielding against various types of radiation, making them indispensable for applications in medicine and the nuclear industry. In this article, we take a look at some of the most common applications of radiation-shielding glass, and the ways in which glass can be modified to shield against radiation.

History of Glass Radiation Shielding

Discovery of x-rays by Roentgen in 1895 was followed by a flurry of x-ray research: around 1000 x-ray research papers were published within a single year. Unfortunately, scientists of the time were late to establish that x-rays were capable of damaging living tissue. By the end of 1896, numerous cases of x-ray dermatitis and more serious conditions were reported within the scientific community.1

Though the risks of radiation exposure were not quickly accepted, radiation shielding equipment was developed as early as 1896. Many of these early interventions made use of lead glass to absorb radiation: These included lead glass backings for fluorescent screens, and thick lead glass goggles to protect against cataracts.

Glass as a Radiation Shield

Today, lead glass and other types of specialized glass are considered vital materials for protection against radiation exposure. As well as offering tunable mechanical, chemical and optical properties, glasses that contain lead strongly absorb gamma, x-ray, and neutron radiation. This unique set of properties makes glass an invaluable radiation shield for applications where line-of-sight is required, such as in medical radiography and nuclear fuel processing.

In many of these applications, radiation-shielding glass finds use in the form of containers known as hot cells and gloveboxes. Both are shielded containers with radiation-proof glass viewing windows, used for the safe storage and manipulation of radioactive materials. Hot cells are more thoroughly shielded heavy-duty containers used for high-intensity radiation sources such as spent nuclear fuel rods. Gloveboxes are used for lower intensity radiation sources such as certain radiopharmaceuticals.

In other areas, screens and windows made from radiation-shielding glass protect healthcare workers and researchers from x-ray sources such as spectrometers and computed tomography (CT) scanners.

Heavy Metal Oxide Glass Modifiers

In general, glasses used for radiation-shielding applications include heavy metal oxide (HMO) modifiers such as lead oxide (PbO) and bismuth oxide (Bi2O3). These chemicals can turn ordinary silicate glass into transparent radiation shields capable of effectively absorbing neutrons, gamma rays and x-rays. The resulting glasses are capable of attenuating radiation at levels comparable to concrete and other standard shielding materials while allowing visible light to pass through.2 Crucially, HMO glasses experience relatively little optical or mechanical degradation as a result of exposure to radiation.

While glasses containing lead oxide are common, increasing the lead content leads to a reduction in both melting point and hardness of the glass.2 This, along with environmental concerns with the use of lead, has encouraged research into other types of HMO glass for radiation shielding applications. These include oxides of boron, tellurium, barium, and silicon.3,4 Some research suggests that these glasses may be able to replace conventional concretes as gamma-ray shielding materials.

Medicine

One key application of radiation-shielding glass is in nuclear medicine. Radioactive sources or materials are used either for imaging purposes (such as positron emission tomography (PET) scans) or therapeutic use (such as radiation therapy). Hot cells and gloveboxes are widely used in the preparation of radiopharmaceuticals, where they allow personnel to process radioactive substances without exposure to dangerous amounts of radiation. Material handling is achieved with the use of remote manipulators or shielded gloves, while radiation-shielded glass windows allow personnel to see inside.

Radiographers are also at risk of exposure to harmful radiation. While scans such as x-rays are generally considered acceptably safe for use in the diagnosis of medical conditions, radiographers carrying out multiple scans per day rely on radiation shielding to minimize their exposure to radiation. Leaded glass windows can strongly absorb both x-rays and gamma rays, allowing radiographers to oversee x-ray or PET scans without exposing themselves to harmful levels of radiation.

Nuclear

Effective radiation shielding is of paramount importance throughout the nuclear industry. Nuclear reactors, spent fuel rods, and fission byproducts all produce many types of harmful radiation in large quantities. Some of these types of radiation are more easily shielded than others: for example, alpha and beta radiation are easily shielded by a thin layer of aluminum or acrylic. However, other radiation types such as gamma, x-ray, and neutron emission can be more challenging to protect against.

Typically, these types of radiation are attenuated by thick concrete shielding. However, in waste reprocessing and laboratory applications, windows of radiation-shielding glass can be used to enable workers to safely view radioactive materials during processing.

Other Applications

Radiation-shielding glass is used in many other applications throughout research and industry, for example in cyclotron maintenance, non-destructive materials testing, and the construction of airport x-ray machines.5 Glass is also used for radiation shielding in space technology for protecting both humans and equipment from cosmic rays — an application for which Mo-Sci is currently developing a lightweight radiation-shielding glass.

References and Further Reading

1. Brodsky, A., Consultants, A. B. & Ronald, M. Historical Development of Radiation Safety Practices in Radiology.
2. Manohara, S. R., Hanagodimath, S. M. & Gerward, L. Photon interaction and energy absorption in glass: A transparent gamma ray shield. J. Nucl. Mater. 393, 465–472 (2009).
3. Lakshminarayana, G. et al. B2O3–Bi2O3–TeO2–BaO and TeO2–Bi2O3–BaO glass systems: a comparative assessment of gamma-ray and fast and thermal neutron attenuation aspects. Appl. Phys. A Mater. Sci. Process. 126, 1–18 (2020).
4. Singh, K. J., Kaur, S. & Kaundal, R. S. Comparative study of gamma ray shielding and some properties of PbO-SiO2-Al2O3 and Bi2O3-SiO2-Al2O3 glass systems. Radiat. Phys. Chem. 96, 153–157 (2014).
5. Manonara, S. R., Hanagodimath, S. M., Gerward, L. & Mittal, K. C. Exposure Buildup Factors for Heavy Metal Oxide Glass: A Radiation Shield. J. Korean Phys. Soc. 59, 2039–2042 (2011).

Hot-Melt Adhesive

Some people have begun using glue guns to stabilise their glass before transporting to the kiln.  These use glue sticks which are a hot melt adhesive.

Hot melt adhesive, or hot glue, is a form of thermoplastic.  It is commonly sold in solid cylindrical sticks of various diameters designed to be applied using a hot glue gun. The gun uses a heating element to melt the plastic glue. The glue is tacky when hot, and solidifies in a few seconds to a minute. The glue squeezed out of the heated nozzle is initially hot enough to burn and even blister skin.

The glue sticks are available in a variety of melt temperatures.  The standard and most commonly available glue sticks are white to cream in colour and the guns have an orange applicator.  The hot glue is delivered from non-adjustable guns at about 195°C.  This is hot enough to burn skin and the possibility of heat shocking the glass should be considered.

3M make a low temperature variety of hot melt adhesive which needs low temperature glue guns – the 3M version is blue, and the sticks contain LT as the suffix to the part number.  This is applied at 129°C.  This is still hot enough to burn skin, but possibly with less risk of thermal shock to the glass.

The risks of breaking the glass from the heat of the glue is one of the risks.   The greater risk is of the effects of the thermo plastic on the surface of the glass.  The glue is a plastic. All of us who have left a plastic item in the kiln can witness to the black smoke created.  So, it won’t do your kiln much good, and will require firing empty to burn out all of the plastic residue. 

It also will not do you glass much good.  The thermo plastic melts and will vaporise at some (unknown) temperature.  But it will leave a residue for the process of devitrification to develop.

My recommendation is to avoid the use of hot melt adhesives for anything going into the kiln.  It is most likely to cause difficulties with the kiln and the glass.