Repoussé and chasing - Hammering Iron Bloom - Weather Vane

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• published: 31 Mar 2015
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In this clip from Edwardian Farm, the blacksmith from Finch Foundry uses repoussé and chasing to create a copper cockerel for a weather vane. Having made charcoal and a bloomery the team removes the iron bloom to make the vane's support pole. Repoussé or repoussage is a metalworking technique in which a malleable metal is ornamented or shaped by hammering from the reverse side to create a design in low relief. Chasing is the opposite technique to repoussé, and the two are used in conjunction to create a finished piece. It is also known as embossing. While repoussé is used to work on the reverse of the metal to form a raised design on the front, chasing is used to refine the design on the front of the work by sinking the metal. The term chasing is derived from the noun "chase", which refers to a groove, furrow, channel or indentation. The adjectival form is "chased work". The process is relatively slow, but a maximum of form is achieved, with one continuous surface of sheet metal of essentially the same thickness. The process of chasing / repousse takes a lot of time due to the repetition of a number of time-consuming stages: The first step is the preparation of the metal by annealing; cleaning to remove the pitch between annealing and work; setting up; and careful work with punches. This process is typically repeated many times during the creation of a chasing/repousse work. One method of repoussé and chasing is to place a thin sheet of metal on a bowl of chasers pitch. This chasers pitch can be pine rosin–based that can be kept slightly soft with a heat gun or plumbers torch for relief work and hardens when cooled for chasing/planishing work. The purpose of using pitch is to provide a solid base to work on, whilst allowing the metal to be pushed out and shaped without obstruction. The pitch is best worked on in a pitch bowl or "pitch board." The pitch bowl is a cast iron bowl which sits on a bag stuffed with sand or on a rubber ring specifically made for this purpose. This allows for greater stability, rotation and angling. There are few techniques that offer such diversity of expression while still being relatively economical. The techniques of repoussé date from Antiquity and have been used widely with gold and silver for fine detailed work and with copper, tin, and bronze for larger sculptures. Classical pieces using this technique include the bronze Greek armour plates from the 3rd century BC. Pitch – resin – pine root magic: https://www.youtube.com/watch?v=sHtgChspAXw The traditional working surface is chaser's pitch which is usually a composition combining three substances: pure pitch, a filler (or stiffener), and an emollient (softening medium). There are a number of different recipes for making chaser's pitch. One example is: • 16 parts pitch • 20 parts plaster of Paris • 4 parts resin • 1 part tallow The pitch is heated until molten. Plaster of Paris is added a small amount at a time. Resin and tallow are then mixed in. During the 3rd millennium BC, in the Middle East, a variety of semi-mass production methods were introduced to avoid repetitive free-hand work. With the simplest technique, sheet gold could be pressed into designs carved in intaglio in stone, bone, metal or even materials such as jet. The use of patterned punches dates back to the first half of the 2nd millennium BC, if not far earlier. The simplest patterned punches were produced by loops or scrolls of wire. By Hellenistic times, combined punches and dies were in use. In 1400 BC, the Egyptian Amarna period, resin and mud for repoussé backing was in use. In 400 BC, the Greeks were using Beeswax for filler in repoussé. http://en.wikipedia.org/wiki/Repouss%C3%A9_and_chasing Bloomery: https://www.youtube.com/watch?v=bajwZPebm-g Charcoal clamp: https://www.youtube.com/watch?v=1yK0rLQa3j4 Pitch - Resin: https://www.youtube.com/watch?v=sHtgChspAXw