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Thrown handles and English jugs
A difficulty in identifying thrown handles on English jugs arises because most handles which appear to have been thrown and cut could easily have been made by other means. The thin and even width of the strap, its cut and sometimes underturned edge and the presence of throwing lines, sometimes faintly on the unserside, are diagnostic features rarely encountered together on English vessels.
Some Tudor Green handles preserve these features more or less intact, but without the underturned edge (e.g. B212, British Museum). A number of Stamford handles may be wheel thrown; and 16th century handles with an underturned edge, from the Lower Parrock kilns, are similar in technique to French examples.
Other handles
A number of French vessels have tubular handles made from a thin clay slab rolled and joined to form a hollow pipe. Apart from puzzle jugs, they rarely occur on English jugs. Fluted handles can be made by pulling a plain rod handle and using the tip of the thumb or finger to make a series of parallel flutes along its length; for fine fluting an improvised tool may be used instead.
The cable handle is a striking variation. A fluted handle is given a twist of one or two turns either before or after attachment to the top of the pot, often with imposing thumb impressions anchoring the flutes at the sides. Almost all medieval cable handles turn in a counter-clockwise direction (left, Grimston cable handle).
Handle Clay
Handle problems begin with the clay, and clay as dug from the ground is notoriously variable. A difficult clay can sometimes be blended with one having complementary characteristics, e.g. a short clay combined with a plastic body prone to excessive shrinkage may produce something workable for handles and throwing. The addition of non-plastic material to clays is a common and often necessary expedient. Plasticity and wheel performance is improved in clays containing, roughly, from 10-20% medium-to-fine sand or grog - a mixed river sand is ideal - and over-all shrinkage will be reduced. In practice the quantity of filler which a particular clay will take is determined chiefly by the loss of plasticity which a potter is prepared to tolerate.
If the clay body is plastic with a good open texture, handles can be made from the same clay as the body to promote uniformity in drying and shrinking. Thick handles are very likely to need some additional coarse sand to give a margin of safety and this may result in a detectable difference in the fabric.
Examples occur where handle and body clays are altogether different, and caution is needed in judging whether the change is deliberate or due to the inadvertent use of a different clay.
Drying and Shrinkage
The production of handles is closely bound up with the drying of clay. During the period of drying and shrinking stresses occur within the clay body which affect the attachment of handles. Linear shrinkage causes compression of the walls between the top and bottom of a pot. resulting in a reduction in height. When a handle is attached at two points early in the drying period they will draw closer together as water is evaporated. The handle will bow outwards, putting the attachments under strain. If the handle should be much drier than the body of the pot and be inflexible it will almost certainly crack.
The extent of shrinkage is shown by noting, for example, that a jug with a fired height of 33cm will have been thrown to a height of about 38cm (left, for illustration only)
Remedial measures
Many medieval handles appear to have been made generously oversize in the wet state. When pulled to the dimensions of handles on fired pots they shrink to a size well below them - this is particularly noticeable with rod handles. Since shrinkage is greater in cross-section than along a handle's length, a rod must be pulled with a much enlarged section if it is to appear as it should on the finished jug. Additional sand, or possibly incising, may be needed to accommodate the extra clay in a successful firing..
A handle may have numerous incisions - stabbing, slicing, piercing - along its length and at handle junctions(left). This visually striking remedy reduces the moisture gradient and promotes even drying and firing by exposing the interior of the handle to evaporation.
Handle displacement
When a pot is collared on the wheel its diameter is reduced by applying inward pressure with the hands while increasing the peripheral speed of the clay - the most common examples are tall balusters with collared necks and bases, or rounded jugs where the neck diameter is reduced in throwing. With most clays this compression causes the overlapping clay platelets to become misaligned in bunches, creating spiral compression ridges or 'collaring lines' twisting around the circumference of the collared parts.
Collaring lines are a reliable indicator of the direction of movement of the wheel in throwing: the collaring lines are swept back at an acute angle away from the direction of wheel turn (see left).
'Plastic Memory'
On a counter-clockwise wheel this compression turns the collared area clockwise, and deforms the alignment of clay particles imparted by the initial throwing. During the period of drying the clockwise movement resumes and continues when the pot is fired. It is a familiar problem for the maker of teapot spouts. Like the collared top of a vessel, the collared spout twists to the left. The clay appears to have a plastic memory of its deformation to which it inconveniently returns.
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