Tyrolean stove project
Introduction
The project involved the reconstruction of an early 17th century Tyrolean stove using over 200 tin-glazed earthenware polychrome ceramic tiles in 24 different shapes with varied dimensions within each shape, including 5 large 3-D lions. Most of the tiles had areas of loss.
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Two significant challenges in the project were:
- the shape of the stove was unknown and had to be ascertained whilst maintaining the ethical concerns for the original object and the need, as conservator, to preserve its aesthetic whole;
- the physical scale of the project (the stove is approximately three metres high and one metre square at its base in reconstructed form). The stove’s construction had to be organised so that it could be assembled/disassembled at different locations by exhibition staff or art shippers in a foolproof manner.
To resolve these problems the required skills involved: analysis, advanced research and project management techniques; examination and observation skills; routine testing of materials and techniques to be carried out; restoration of tiles including the recreation of missing material/areas of loss and the creation of facsimile tiles; technical and design innovations, problem solving abilities and the creation of a built-in flexible design.
The project was successful in achieving a simple functional assembly/disassembly method which ensured the integrity and safety of the object and those erecting it, whilst maintaining ethical good practice. As conservator, I was consulted and involved with the decision-making processes at all stages, ensuring a successful outcome and the long term sustainability of the completed stove. Successful collaboration within and outside the conservation community introduced innovative support and attachment mechanisms to the conservation profession.
Nigel Williams Award essay
Introduction
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At the outset of the project the conservator was presented with the tiles lying loose in boxes with very little indication of how they should be arranged and with no existing support structure [Fig 1]. On completion of the project the reconstructed object was a three metre high by one metre square (at its base) ceramic stove made up of over 200 tiles of various sizes, shapes and polychrome decorative styles [Fig 2].
Historical and Contextual Research
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Historical research indicated that the stove was built in the early 1600s, in Austria. The date and place were confirmed by discovering very similar tiles on the Mitterlana stove at the Volkskunstmuseum in Innsbruck [Fig 3] and the date was further confirmed by dating the style of clothing depicted on the tiles [Fig 4].
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The stove would have been built ‘in situ’ in a large house by a stove maker. It would have been a unique design based on the shape and size of the room and the tiles would have been purchased from a selection of ready-made tiles from a local potter or manufacturer. As the stove has been moved from its original setting all context is lost.
In its original form the stove would have been constructed against a wall, behind which would have been a fire place and stokehole. The heat and smoke would have risen from the fire and been directed into the stove. The smoke would then have passed through a flue, back into the outside chamber and from there vented by some form of chimney to the outside.
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From this historical evidence, examination of the stove and observations from an earlier conservation report (which outlined the removal of much plaster and restoration of broken tiles) it was possible to determine the changes in form and function that the stove had undergone. The stove had been dismantled from its original setting and a brass fire door ‘retro-fitted’ in the mid to late 19th century. It had been reconstructed with much plaster at some point: probably sometime after the door had been added. In the early 20th century, the stove was again dismantled and packed in boxes until it was purchased by the current owners.
Documentation and Project Management
Once removed from the 30 boxes they arrived in, an early task was to assess and catalogue all the tiles and 3-D lions. The following documents and reports were compiled:
- digital photography of each tile from at least two angles;
- condition report noting previous recent conservation carried out for each tile;
- various inventories; including description as described on box and matched to what was received, tile description including any previous numbering or markings, shape of tile and tile type and noting their complexities, allocating and inscribing individual numbers for each tile, noting whether the tile was whole or part or cut;
- proposed conservation reports and lists establishing missing tiles.
It was then possible to start formulating a project plan and producing schedules for the project . These documents were written for each stage including research and testing which informed the methods of treatment to be used and were updated throughout the project, to completion, within a tight deadline in order to meet the Owners’ wish to exhibit at the European Fine Art Fair, Maastricht in March 2005.
The scale of the project required theoretical and practical skills together with these project management practices in order to manage the tasks of restoring the stove (including replacing missing tiles and areas of loss), the design and implementation of the attachments and the design of the support and frame, all of which tasks were individually complex.
Interpersonal skills were important in order to manage a diverse project team. These included craftsmen, a blacksmith, metals workers and conservators, assistants with the steel structure and carbon fibre frame, ceramic conservators, packers and an assembly team. The timely co-ordination of supplies, delivery and equipment hire were essential for the smooth running of the project.
Insurance was obtained and COSSH forms were filed for restoration materials.
The preparation of conservation reports and assembly/disassembly instructions also had to be factored in. In addition, at critical decision making stages, conference with the owners was crucial to understanding their requirements and agreeing the necessary conservation and restoration procedures.
ConFiguration of original tiles
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A major task was to research the original shape of the stove and conFiguration of the tiles and ‘lion’ elements. Drawings, measurements, dry run layouts, close observations and a 3-D model were made to ascertain the shape of the stove [Figs 5, 6, 7]. To produce that accurate model, digital photographs were taken of each tile from the same distance and printed to the same scale. These were cut out and pasted together describing the most recent conFiguration of the stove ie with the stove door. Using the historical evidence of the original function and form of the stove and the same technique as used for the first model it was possible ‘to rearrange the tiles’ omitting the ‘retro-fitted’ brass door to produce a second model describing the most likely form of the original stove. In order to accommodate the fire box door some of the tiles had been cut and the second model was made on the premise that these tiles would be restored and facsimiles made of the missing tiles.
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In light of the research, my detailed findings, the prepared models and subsequent discussion with the owners, a number of curatorial decisions were taken, and a work-plan determined. The brass door was to be omitted and the cut and damaged tiles were to be restored and made whole again. Missing tiles were to be made up with facsimiles in easy to detect plaster. Some tiles, which would be at the back of the stove, would be facsimile casts but with a restricted palette.
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The Owners’ final brief was that the remedial conservation-restoration of the damaged ceramic components should be completed, in particular to the five lion supports to reassemble the original and facsimile replacement tiles into a stove, in its original conFiguration. The stove would be a decorative art object and not a working stove but which could be assembled and disassembled.
Design and Making the Frame and Support
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The use of crossover technologies from outside conservation introduced carbon fibre board from the aircraft and racing car industry to make a support which resolved difficulties of size versus strength.
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The carbon fibre board (4 mm) was used for the chimney section [Fig 8] where anything thicker would not have fitted between the layers or sections and glass fibre (15 mm) boards for the firebox section [Fig 9] which had the space but required a material which would not flex.
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A system was devised by which various attachments were bonded to the tiles and bolted to the frame [Fig 10]. The bonding of boards, strengthening of holes and bonding of bolts to board were done with Araldite 20/15 (Epoxy Resin). 6 mm bolts, washers and wing nuts and nuts were used; also a selection of mending plates, angle brackets and T bars made from steel and galvanised zinc. Bolts, mending plates and brackets from the building trade to attach made use of a ready supply of good quality materials.
An overall design was sketched out which had three important concepts at its heart:
- Flexibility was built into the design for the frame, support mechanism and sections: in concept, as exact measurements could only be taken as each layer was constructed; and in application, so that it could be altered and refined until an exact fit was achieved [Fig 11] that would safely carry the tiles (so that the weight of one layer did not touch or impact on a neighbouring layer, the aesthetic look was preserved and the viewing public would be safe).
- The system for connecting the sections of frame together had to allow for different sizes of frame to be supported one on top of the other
- The system had to be logical and clear to aid shippers or exhibition staff who would construct the stove.
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For the firebox section, a steel frame was designed and built which would support the load of the chimney with ease and had to be stable enough to allow uneven loading of the side panels and not tip over. But care, however, had to be taken to keep the weight down for health and safety reason during transport and assembly / disassembly.
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The main structure of the frame was fabricated in 25 mm box steel but angle steel was used where possible to reduce weight. Spot welding was used were possible for strength; otherwise, sections were bolted with 6 mm bolts, washers and wing nuts were used where practicable. A concept for the frame was designed using a system of spigots and steel box slots spaced with washers for extra fine tuning.
The glass fibre panels were attached to the front and two sides in three layers. Handles and fibre board hand holds were incorporated into the design to take the weight when carried, thereby preventing pressure from being applied to the tiles. It was integral to the design that each tile only had to carry its own weight.
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The chimney was made in a series of sections [Figs 13 & 14] starting from the lowest with each section presenting a different set of challenges. Not least of which was that incomplete tile backs presented different heights and dimensions [Fig15]. This required the attachment method to be flexible enough to support the different profiles offered. Each section consisted of a layer or layers of tiles with attachments bolted to carbon boards which, for strength, were made up into drum shapes. The drums were in turn attached to a section of steel frame
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It was impossible to work out the exact measurements for the frame for each section until each layer had been supported on boards and bolted in their approximate position. Once a section of frame was made and the supporting boards attached to the frame, the tile attachments were adjusted to achieve the straightest line and most even distribution possible.
Restoration
The methods used for the restoration of the lions, the cut and damaged tiles, and the making of replacement facsimiles was conventional.
The removal of previous restoration to the lions was important as the plaster and cement within the lions was putting pressure on the soft earthenware bodies forcing breaks along mould lines and firing cracks. After removing the plaster and cement, the sherds were cleaned with water to which was added a few drops of diluted Synperonic A7 (non ionic detergent) and 10% Industrial Methylated Spirits (IMS). Acetone and IMS were used to remove previous adhesive. Break edges were consolidated with Paraloid B72 at 10% in acetone. Bonding was achieved with Araldite 20/20 Epoxy Resin bulked with fumed silica. Small gap filling and replacement casts were made in dental plaster. Retouching was applied with Goldens Restoration Porcelain Gloss glaze and dry powder pigments.
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The moulding and casting of replacement parts to the lions and cut tiles were made by making an Ambersil Silcoset 105 RTV silicone rubber mould (bulked with fumed silica to provide necessary strength) of a whole or part tile or lion section, making a wax cast and refining the wax cast to match. A further Silcoset 105 mould was made of the wax cast in situ from which a dental plaster tile or area of loss was finally made. These were then further refined to fit. The plaster casts and break edges of the lions and tiles were consolidated with Paraloid B72 at 10% in acetone and the casts were bonded with Araldite 20/20 bulked with fumed silica (if large or structurally supportive) otherwise bonded with Paraloid B72 at 50% in acetone. Casts were retouched with Goldens Restoration Glaze and dry powder pigments.
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For the replacement and facsimile tiles, moulds were made using Silcoset 105 or dental wax (modelling clay or clay was also used to hold the position of moulding material) [Fig 16]. Mother moulds where created in fibre glass and polyurethane resin. Dental plaster casts were retouched with Goldens Restoration Glaze and dry powder pigments. Facsimile tiles, however, were kept to a minimum by making maximum use of original material.
After testing for reversibility and consolidating the tile edges the completed sections and panels were grouted with a mix of Tetrion in 10% PVA/water. Care was taken not to fill too deeply for ease of reversibility. Sections were put together and separated with either Melinex or Clingfilm and the ‘grouting’ applied to one side. Once cured the separating film was removed. This ensured that the gaps between sections were filled. The grouting helped hold the tiles securely in place especially during transport.
Bonding attachments to tiles
Tests were conducted on earthenware sherds to establish a preferred technique and assess for reversibility. The method chosen was to consolidate the earthenware with Paraloid B72 at 10% in acetone and bond with Araldite 20/20 bulked with fumed silica. Each tile was fixed to a board support by a steel/galvanized zinc attachment bonded to the back of the tile [Fig 9, 10 & 13]. The exact design of the attachment varied according to the size and shape of the tile.
Technique of assembly/disassembly for display
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Each section could be carried by two men by either the frame itself or ropes (well over one ton breaking) attached to the frame through which a carrying beam, could be passed so that the section could be lifted and lowered into place [Fig 17]. Rope was used because, when not needed, it would collapse within the drum and not get in the way of the next section [Fig 18]. It also saved on weight. Prime importance was to prevent any weight or pressure being put on the tiles while the sections were being handled in transit.
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Each section of chimney slotted onto the frame one on top of the other with the weight of each being taken by the frame. Scaffolding towers [Fig 19] were used to ensure that safety requirements were complied with as part of continuing risk assessments made throughout the project.
Boxing Up and Transport
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Each section of stove was measured up for an individual packing case made of wood and lined with inert foam (and acid free paper) which was cut to ensure the section fitted ‘snugly’ into the box [Fig 20]. The boxes were used to ship the stove to Maastricht and back to the UK where it was erected at amongst other places, the Grosvenor House Antiques Fair. Full instructions for the erecting of the stove accompanied the boxes which augmented the numbering system inscribed on the inside of the boards.
Potential wider benefit
Because of their physical weight and original construction, museums have tended to reconstruct ceramic stoves permanently, within galleries. This project devised a methodology which allowed for complicated, heavy and multifaceted objects to be reconstructed in a way that would enable them to be moved to another location or gallery for greater access. In addition, the system of tile attachment allows for flexibility so that the form of the stove can be changed, better to reflect historical accuracy in light of any further scholarship.
Although this support mechanism was particular to the stove, these techniques could be applied to many large objects which require a hidden load bearing support.
It is feasible that this method could open up the opportunity for collections of stove or wall tiles, pavements, kilns or architectural ceramics to be reconstructed into a meaningful object where hitherto they may have lain in storage, with no possibility of being displayed due to the lack of method to do so.
Communication of the project
- European Fine Art Fair, Maastricht, March 2005, exhibited
- BBC South 6 O’Clock News, July 2004 >
- CGCG (UKIC) Conference, Ironbridge 1st to 3rd April 2005, lecture
- MA thesis, West Dean College library, and from author on request
- West Dean College, MA in Conservation Studies course, lecture on Project Management 18th May 2005
- Grosvenor House Antiques Fair, June 2005, exhibited