 Care: Wash by hand in lukewarm water. FAQ What is thermal shock? Thermal shock is caused by rapid temper change; this may be from hot to cold or cold to hot. Some of the glasses are made up of both thick pieces and thin pieces of glass. For example, the jugs, which are thick at the handle and base and thin throughout the trunk. When the thin pieces change temperature they expand or contract while the thicker pieces remain the same, this causes friction and the piece may crack. Another example of thermal shock is when candles are allowed to burn too closely to the rim of the candleholders causing rapid temperature change.Why do size and height variations occur in the glass? Simply because Jerpoint is completely made and finished by hand. The glassblowers use their own creative judgement to determine the correct shape of the finished piece. We do not use moulds to mass-produce glass and we do not cut the glass to shape. It is because of the techniques used at Jerpoint that each piece of glass is unique. Why do the shades of colour vary in Jerpoint Glass? The nature of and indeed the beauty of Jerpoint is that each piece is individually handmade and finished. The glass gathers are dipped into the colour and then introduced into the glass it is measured using the glassblowers’ skill and experience and may vary slightly. Also, we buy our colour in granulated form; the colour itself is mixed by hand and therefor also varies from one batch to another. How do we get the colour into the glass? The colour is made of chipped glass, which has had an oxidant added to it, for example cobalt makes blue. The oxidant reacts with the glass and causes it to become pigmented. The glassblower dips their gather of hot molten glass from the furnace into a tray of colour once it is added to the glass it fuses together and creates coloured glass. What is the mark found on the bottom of the glasses? The mark on the bottom of the glass is known as the pontil mark. Jerpoint Glass is made and finished by hand. Jerpoint has a very soft and durable rim because we finish each piece by hand. During the glass making process the cup part of the glass is closed and attached to the blowing iron. In order to open the cup we transfer the glass onto a second iron at the base, the pontil iron it is then reheated and open out at the rim. The pontil leaves a mark under the glass where they have been attached. It is this process that sets us apart from other glass manufacturers who crack the glass away from the blowing iron and cut the tops off. Why are there bubbles in the glass? Bubbles appear in the glass because it is hand blown glass. The shapes are formed literally with the craftsmen’s breath. We can get rid of some of the larger bubbles, however some bubbles remain in the glass. Bubbles are part and parcel of hand made glass and part of their charm. What is glass made of? There are many recipes for making glass. The Jerpoint Glass has thirteen ingredients approximately 50% of which is silica sand. Other ingredients include potash, lime and borax. How hot is the furnace? The furnace runs at 1430 degrees C when melting and 1170 degrees C when glassmaking. Do you train the glassblowers yourselves? Yes! It takes between five and seven years to be accomplished enough to head a glassblowing team. Although you could never say that a glassblower was fully trained as glassblowing is constantly changing and developing. |