HMG Heat and Waterproof Adhesive (also known as HMG or HMG adhesive) is a brand of cellulose nitrate adhesive manufactured by H Marcel Guest Ltd. It is one of the most popular cellulose nitrate adhesives used in conservation and restoration work, and is used on materials such as metal, wood, glass, and pottery. [1] [2] [3] It is sometimes referred to as "the blue tube", in contrast to "the purple tube", the acrylic B72 Restoration Adhesive also manufactured by the company. [4]
HMG was invented during World War II by the company's founder, Herbert Falder. [4] Today it is broadly used, including by the British Museum and the York Archaeological Trust. In 1997, HMG was used to adhere pieces of the Anglo-Saxon Pioneer helmet, which was found broken into between 100 and 200 fragments. [5] [6] Particularly fragile areas had their cracks injected with a solution of HMG diluted 50% with acetone, to consolidate them and prevent them from collapsing; holes made while cleaning away corrosion were likewise injected with pigmented HMG. [7] [8] Stronger areas, such as the sinister cheek guard, found in eighteen pieces, and the nasal, were joined directly with the adhesive. [9] Finally, HMG was also used to adhere glass fibre matting on the inside of the helmet, strengthening weak joins and covering gaps, the latter to provide backing against which gapfill could be applied. [10] [11]
HMG is advertised with a −18 °C (0 °F) flash point, and a 100 °C (212 °F) temperature resistance. [2] It is insoluble in water and soluble in acetone, and is composed of 70% amyl acetate solvent, 25% cellulose nitrate, approximately 5% of the plasticizer dibutyl phthalate, [12] and a small amount of a phenolic resin leveling agent. [3] The adhesive is touch dry in five minutes, and hard dry in ten. [4]
The Benty Grange helmet is a boar-crested Anglo-Saxon helmet from the 7th century AD. It was excavated by Thomas Bateman in 1848 from a tumulus at the Benty Grange farm in Monyash in western Derbyshire. The grave had probably been looted by the time of Bateman's excavation, but still contained other high-status objects suggestive of a richly furnished burial, such as the fragmentary remains of a hanging bowl. The helmet is displayed at Sheffield's Weston Park Museum, which purchased it from Bateman's estate in 1893.
Methyl cellulose is a chemical compound derived from cellulose. It is sold under a variety of trade names and is used as a thickener and emulsifier in various food and cosmetic products, and also as a bulk-forming laxative. Like cellulose, it is not digestible, not toxic, and not an allergen.
The Coppergate Helmet is an eighth-century Anglo-Saxon helmet found in York, England. It was discovered in May 1982 during excavations for the Jorvik Viking Centre at the bottom of a pit that is thought to have once been a well.
The Sutton Hoo helmet is an ornately decorated Anglo-Saxon helmet found during a 1939 excavation of the Sutton Hoo ship-burial. It was buried around 625 and is widely associated with King Rædwald of East Anglia; its elaborate decoration may have given it a secondary function akin to a crown. The helmet was both a functional piece of armour that would have offered considerable protection if ever used in warfare, and a decorative, prestigious piece of extravagant metalwork. It is described as "the most iconic object" from "one of the most spectacular archaeological discoveries ever made", and perhaps the most important known Anglo-Saxon artefact.
Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. It is also used for reinforcing closed plywood structures. The de Havilland Mosquito is an example of this technique, as are the pioneering all-wood monocoque fuselages of certain World War I German aircraft like the LFG Roland C.II in its wrapped Wickelrumpf plywood strip and fabric covering.
The Pioneer Helmet is a boar-crested Anglo-Saxon helmet from the late seventh century found in Wollaston, Northamptonshire, United Kingdom. It was discovered during a March 1997 excavation before the land was to be mined for gravel and was part of the grave of a young man. Other objects in the grave, such as a hanging bowl and a pattern welded sword, suggest that it was the burial mound of a high-status warrior.
The conservation and restoration of silver objects is an activity dedicated to the preservation and protection of objects of historical and personal value made from silver. When applied to cultural heritage this activity is generally undertaken by a conservator-restorer.
Conservation and restoration of ceramic objects is a process dedicated to the preservation and protection of objects of historical and personal value made from ceramic. Typically this activity of conservation-restoration is undertaken by a conservator-restorer, especially when dealing with an object of cultural heritage. Ceramics are created from a production of coatings of inorganic, nonmetallic materials using heating and cooling to create a glaze. Typically the coatings are permanent and sustainable for utilitarian and decorative purposes. The cleaning, handling, storage, and in general treatment of ceramics is consistent with that of glass because they are made of similar oxygen-rich components, such as silicates. In conservation ceramics are broken down into three groups: unfired clay, earthenware or terracotta, and stoneware and porcelain.
Paraloid B-72 or B-72 is a thermoplastic resin that was created by Rohm and Haas for use as a surface coating and as a vehicle for flexographic ink. Today B-72 is commonly being used as an adhesive by conservator-restorers, specifically in the conservation and restoration of ceramic objects, glass objects, the preparation of fossils, the hardening of piano hammers, and can also be used for labeling museum objects.
The Shorwell helmet is an Anglo-Saxon helmet from the early to mid-sixth century AD found near Shorwell on the Isle of Wight in southern England. It was one of the grave goods of a high-status Anglo-Saxon warrior, and was found with other objects such as a pattern-welded sword and hanging bowl. One of only six known Anglo-Saxon helmets, alongside those from Benty Grange, Sutton Hoo, Coppergate, Wollaston, and Staffordshire, it is the sole example to derive from the continental Frankish style rather than the contemporaneous Northern "crested helmets" used in England and Scandinavia.
The conservation and restoration of books, manuscripts, documents and ephemera is an activity dedicated to the preservation and protection of items of historical and personal value made primarily from paper, parchment, and leather. When applied to cultural heritage, conservation activities are generally undertaken by a conservator. The primary goal of conservation is to preserve the lifespan of the object as well as maintaining its integrity by keeping all additions reversible. Conservation of books and paper involves techniques of bookbinding, restoration, paper chemistry, and other material technologies including preservation and archival techniques.
Conservation and restoration of objects made from plastics is work dedicated to the conservation of objects of historical and personal value made from plastics. When applied to cultural heritage, this activity is generally undertaken by a conservator-restorer.
The conservation and restoration of paintings is carried out by professional painting conservators. Paintings cover a wide range of various mediums, materials, and their supports. Painting types include fine art to decorative and functional objects spanning from acrylics, frescoes, and oil paint on various surfaces, egg tempera on panels and canvas, lacquer painting, water color and more. Knowing the materials of any given painting and its support allows for the proper restoration and conservation practices. All components of a painting will react to its environment differently, and impact the artwork as a whole. These material components along with collections care will determine the longevity of a painting. The first steps to conservation and restoration is preventive conservation followed by active restoration with the artist's intent in mind.
Nigel Reuben Rook Williams was an English conservator and expert on the restoration of ceramics and glass. From 1961 until his death he worked at the British Museum, where he became the Chief Conservator of Ceramics and Glass in 1983. There his work included the successful restorations of the Sutton Hoo helmet and the Portland Vase.
The conservation and restoration of film is the physical care and treatment of film-based materials. These include photographic film and motion picture film stock.
The conservation and restoration of papyrus material is an activity dedicated to the preservation and protection of objects of historical and personal value made from papyrus from Ancient Egypt.
The conservation-restoration of panel paintings involves preventive and treatment measures taken by paintings conservators to slow deterioration, preserve, and repair damage. Panel paintings consist of a wood support, a ground, and an image layer. They are typically constructed of two or more panels joined together by crossbeam braces which can separate due to age and material instability caused by fluctuations in relative humidity and temperature. These factors compromise structural integrity and can lead to warping and paint flaking. Because wood is particularly susceptible to pest damage, an IPM plan and regulation of the conditions in storage and display are essential. Past treatments that have fallen out of favor because they can cause permanent damage include transfer of the painting onto a new support, planing, and heavy cradling. Today's conservators often have to remediate damage from previous restoration efforts. Modern conservation-restoration techniques favor minimal intervention that accommodates wood's natural tendency to react to environmental changes. Treatments may include applying flexible battens to minimize deformation or simply leaving distortions alone, instead focusing on preventive care to preserve the artwork in its original state.
Ian David Meadows is a British archaeologist. He has worked in archaeology for some 40 years, including as a Senior Project Officer at Northamptonshire Archaeology from 1992 to 2014. During that time he excavated a number of large quarries in England and Wales, and excavated the boar-crested Anglo-Saxon Pioneer Helmet in addition to discovering the first definitive evidence for viticulture in Roman Britain. He has also worked for the Museum of London Archaeology, and has taught archaeology and landscape history for Cambridge University, Anglia Ruskin University, the University of Bath, and the Workers' Educational Association.
The Guilden Morden boar is a sixth- or seventh-century Anglo-Saxon copper alloy figure of a boar that may have once served as the crest of a helmet. It was found around 1864 or 1865 in a grave in Guilden Morden, a village in the eastern English county of Cambridgeshire. There the boar attended a skeleton with other objects, including a small earthenware bead with an incised pattern, although the boar is all that now remains. Herbert George Fordham, whose father originally discovered the boar, donated it to the British Museum in 1904; as of 2018 it was on view in room 41.
The Horncastle boar's head is an early seventh-century Anglo-Saxon ornament depicting a boar that probably was once part of the crest of a helmet. It was discovered in 2002 by a metal detectorist searching in the town of Horncastle, Lincolnshire. It was reported as found treasure and acquired for £15,000 by the City and County Museum, where it is on permanent display.
