Profile

I live in Sheffield with my husband and 15 year old son – my other son lives in Derby where he goes to University.  We have a dog, cat and 2 rabbits.  I really like making stained glass in my spare time and have set up a small workshop in my garage.

I came to Sheffield to do a degree in Materials science and stayed to do a Masters degree and finally a PhD in materials science specialising in glass.

After I finished my PhD, I worked for a company that did testing and consultancy work for the glass industry.  I did train as a primary school teacher but realised it was not a good fit for me so I returned to the University that I got my degree from as a teaching technician and now run a big lab with a team of technicians.

I am in charge of a team of technicians who process and mechanical test materials at the Department of Materials Science and Engineering at the University of Sheffield.

I work mainly in a big materials processing laboratory where we make new materials – especially metals and glasses.  We have a number of different ways of making and manipulating materials from melting using basic techniques (e.g. melting in furnaces) to more advanced techniques such as powder processing and 3D printing.  Materials can behave in really different ways depending not only on their composition, but also on their microstructure (or how the different crystals fit together) so a lot of our work involves heat treating materials to manipulate their characteristics.

My particular specialism is glass making and teaching metals and glassmaking practicals to our undergraduate and postgraduate taught students. The glasses that I make could range from those to encapsulate nuclear waste materials (as glass is very chemically resistant and can lock up radioactive materials for responsible disposal) to bio-glasses (as glasses can be tailored to enable bone to grow on them).  My team runs 2 major practicals which involve casting aluminium in the first year and glassmaking in the second year of the undergraduate degree in addition to several smaller practicals. In the image we are making Rupert’s drops which are a great way of demonstrating stress in glass. I particularly like it when we run short industrially relevant group project work as some of the ideas to develop can be difficult to put into practice.

Because melting glasses and metals can look visually stimulating, we have been on TV a number of times – most recently NBC News for a piece on encapsulating nuclear waste from Hiroshima in glass, but we have also been on CBBC with Dick and Dom where they melted steel using the Bessemer process for an episode of Absolute Genius.

Before work

I absolutely hate mornings and would much prefer to stay snuggled up under the duvet. The first thing I normally need to do is try and encourage my son to get up and get ready for school which is a battle in itself:-)  I always start the day with a cup of tea to help wake me up…sometimes 2.

At work

I normally start work at 9am.  When I get to work my first job is normally to check that the other 2 technicians working in the materials processing lab are ok and that they have not got any problems that they need help solving.

Glassmelting

If I am melting a glass that day, the student would normally arrive at around 9:30am.  The student will have made up the glassmaking batch at least the day before to make the glass that they want to investigate (the batch is normally made up of a mixture of oxides, carbonates and sometimes nitrates in powder form).  Most students want to melt their glasses using a platinum crucible – these cost around £15000, but are reusable luckily – and will want to make 300g of glass.  As the batch materials are all powders and are not all oxides, the volume of the powders is much bigger than the crucible, so we fill the crucible up in stages allowing some of the batch to react up until all the batch is in the crucible; filling on will typically take 1 hour to do; all this is done with the furnace at the melting temperature so I need to wear a lot of protective equipment.

After 1 hour of melting (up to 1450C in one of the electric furnaces) the starting components will have all reacted and there will be a thick viscous liquid, however this will not be very homogeneous (well mixed) and will still be full of bubbles so we would melt for up to 4 hours further, normally using a stirrer to help mix the glass.   I would need to make sure any moulds that we are using are preheated and the annealing furnace is starting to warm up. During the 4 hours that the glass is ‘cooking’ I would do paperwork things like answering queries, reading papers, looking things up, health and safety, meetings etc.

After the 4 hours is up, the student will return and we would pour the glass.  When I pour the glass it is a really thick liquid – a bit like treacle.  Being a liquid, it fills up the mould.  The mould extracts heat from the hot glass and the liquid thickens up so that it can hold its own shape.  This is not the end though as at this stage, the outside is solid and cold, but the inside of the sample is still very hot and a liquid.  If left to cool like this, the glass would be dangerous with a big tensile stress on the inside and could ‘spontaneously explode’ with only a little bit of heat of surface damage.  We need to therefore do a secondary heat treatment called annealing which removes the stress from inside the glass – this is done at a much cooler temperature than melting and is a slow process – luckily the furnace controllers take charge of doing all of that once they have been programmed.  Annealing is done at a different temperature for different glass types.  Sometimes I might need to make glass fibres or frit (where I would pour hot glass into a bucket of water to produce granulated glass) – these do not need annealing.  Once finished making the glass, cleaning the platinum for the next person starts – this takes another 2 hours of fusions and then finally boiling in hydrochloric acid.

Other activities

Other things that I might do during the day would be to to lead practical classes for students doing high temperature materials processing.  At the moment I am looking at increasing the amount of practicals that we will be able to offer in the future to maybe look at one where we can melt steel.

My team also does a glassmaking demonstration for prospective students and their families – here I would talk a bit about glass and glass colours and show a simple demonstration of pressing a shape into glass and talk about annealing.  We would then go on to talk about toughening and make Rupert’s drops where we would pour the hot glass through a very big sieve into cool water to freeze in the stress.  The resulting drops that look a little bit like tadpoles are really strong and you could hit them with a big hammer and they would not break…however glass is brittle and if you can introduce a crack into it these will explode due to the high tensile stresses locked inside.  The drops have a very thin ‘tail’ and these tails can be bent to start a crack.  We would break these inside students hands to let them experience the energy release when they break – this always goes down really well 🙂