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. 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.
Invention and use
HMG was invented during
World War II by the company's founder, Herbert Falder. 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
The Anglo-Saxons were a Cultural identity, cultural group who inhabited England in the Early Middle Ages. They traced their origins to settlers who came to Britain from mainland Europe in the 5th century. However, the ethnogenesis of the Anglo- ...
Pioneer helmet
The Pioneer Helmet (also known as the Wollaston Helmet or Northamptonshire Helmet) is an Anglo-Saxon boar-crested helmet from the late seventh century found in Wollaston, Northamptonshire, United Kingdom. It was discovered during a March 19 ...
, which was found broken into between 100 and 200 fragments. 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. Stronger areas, such as the
sinister
Sinister commonly refers to:
* Evil
* Ominous
Sinister may also refer to:
Left side
* Sinister, Latin for the direction " left"
* Sinister, in heraldry, is the bearer's true left side (viewers' right side) of an escutcheon or coat of arms; see ...
cheek guard, found in eighteen pieces, and the
nasal
Nasal is an adjective referring to the nose, part of human or animal anatomy. It may also be shorthand for the following uses in combination:
* With reference to the human nose:
** Nasal administration, a method of pharmaceutical drug delivery
** ...
, were joined directly with the adhesive. 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.
Technical properties
HMG is advertised with a
flash point
The flash point of a material is the "lowest liquid temperature at which, under certain standardized conditions, a liquid gives off vapours in a quantity such as to be capable of forming an ignitable vapour/air mixture". (EN 60079-10-1)
The fl ...
, and a temperature resistance. 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, and a small amount of a phenolic resin leveling agent. The adhesive is touch dry in five minutes, and hard dry in ten.
References
Bibliography
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External links
Semiconductors Glue
Adhesives
Brand name materials
Conservation and restoration of cultural heritage