Julian Stray, Assistant Curator, details the process followed by the BPMA Curatorial Department during the restoration of a blue airmail pillar box from the 1930s
Leaflet advertising the airmail service
Special post boxes for the collection of airmail were on British streets for less than nine years yet they continue to fascinate. Originally intended to be placed in prominent positions in London, by 1936, there were 139 in London and 174 in the provinces. Much of the interest in these boxes comes from the colour that they were painted: blue. This advertised the special facilities that they offered such as exceptionally late clearances.
For this reason and due to the general condition of the BPMA’s airmail pillar box (whilst on loan for an extended period it had been exhibited outdoors which caused its condition to deteriorate; some parts of the box were also missing and the box had been re-painted the incorrect colour a number of times) the exceptional decision was made by BPMA to restore it to an appearance contemporary to when it was in use during the mid 1930s. This would enable us to restore not only the pillar box, but also the story…
Airmail box being collected from its outdoor display area prior to restoration
The first step was to assess the extent of the damage to the box and undertake preliminary work. WD40 and Duck Oil were used to loosen bolts, screws and hinges in order to remove them. Wherever possible these were retained for later re-use.
The box was then stripped and shot blasted with aluminium oxide. Care was taken to preserve the sharpness of such features as the maker’s name (Carron), and the George V crown and cipher. Nitromors was used when necessary on some brass work.
The base of the box was bolted to a specially constructed steel pallet. This enables future safe storage, transport and exhibition and is a preferred option frequently employed by BPMA with other boxes in the collection.
Stripped, shot-blasted box painted with red oxide primer
Some original blow holes from the day the box was cast were smoothed out with filler, replicating a practice originally carried out in the foundry. The box was then carefully rubbed down to enable red-oxide primer to be applied. The box and cap were painted separately.
Filler applied to some parts of the pillar box where blow holes were most prevalent
Both the oval, enamel airmail sign on the cap, and the enamel ‘flag’ beneath the aperture were in quite poor condition. It was decided to conserve these in as original condition as possible and commission replicas to be fixed to the restored box. Restoration of the signs would have removed much that is original, and it is highly unlikely that more than a handful of original examples survive today. Such a curatorial decision permits the original signs to be available for research in their original and preserved condition.
Oval sign in original poor and damaged condition prior to return to the BPMA
Stocksigns, based at Redhill were engaged for the work of replicating the airmail signs. Founded in 1955, the company had purchased Burnham Signs (founded 1877) who, in turn, incorporated Garnier & Co. (established 1891). Garnier had been the original supplier of the small airmail signs to the Post Office in the 1930s. This commissioning was an attempt to preserve some continuity of provenance in the restoration.
The original mounting frame for the sign on the cap was also retained to preserve its provenance and act as a record of the colouration of the box for much of its recent time while on display. A contemporary and identical duplicate was located within the BPMA collection. This had been painted red for its working life. This was stripped of paint prior to application of primer.
Determining the original colour of the pillar box proved a challenge. Files relating to the commission and installation of the boxes in the 1930s survive within the Royal Mail archive maintained by BPMA. From these it was established that the blue colour was based on the airmail etiquettes (labels) attached to airmail correspondence at the time. The Technical Advisory Department of PPG Architectural Coatings worked with the BPMA on analysing the colour of a contemporary label. Additionally, paint flecks had been retrieved from the original layer applied to the pillar box and these were also analysed.
Flecks retrieved from the first layer of paint applied to the pillar box
Thankfully, results from both proved identical and a correct shade was established from the Johnstones Natural Colour System. This was S-3050-R90B – a bright and vibrant blue that must have proved extremely eye catching when the boxes were first installed on British streets. It is interesting to note that subsequent re-paints of the airmail boxes in the 1930s frequently employed locally sourced paint and variations in shade would have occurred.
Jonhstones Professional undercoat and Professional gloss paint in the established shade were applied using good quality ½” and 2” brushes. This work was spread over five days. This permitted fine work to be painted, followed by large areas. A 36 hour hardening period was timetabled midway prior to similar applications of top coat. The cap and frame were painted separately and attached to the box once dry.
Julian Stray applies blue undercoat to some of the ‘fine work’ of the prepared pillar box
The base of the box was painted with standard Post Office letter box gloss black: 222T9000, Cromadex, whilst the interior of the pillar box was painted with the correct lead colour: S-7500-N Johnstones durable matt. The steel pallet to which the box was bolted was also similarly painted for a muted appearance during display.
Black paint is applied to the base
Contemporary internal cage and chute were sourced from Romec, the engineering wing of Royal Mail. Bolts for attaching the cap and a new Chubbs lock and four keys were supplied by Goldcrest Extol Ltd. Where possible, original screws and bolts were retained and re-used, however many of these proved to be already damaged or wanting. Correct brass replacements were obtained from Clerkenwell Screws Ltd.
The box is starting to come together
The Royal Mail archive also proved indispensible when researching the collection plate to be replicated and installed in the exhibited box. Research revealed that most current thinking revolving around two enamel collection plates being installed in a dual or double plate holder was incorrect. During the time that these boxes were in use for airmails, Post Office officials understood that such an experimental service would entail frequent alteration of displayed collection times – not least because flight times altered between summer and winter.
Because of the high cost of production of enamel collection plates, it had been decided at the time that simple card plates would be printed by the National Savings Bank. These were eventually produced in a large, landscape format that included detail on both postage and air fees on the right, and times of collection on the left. These notices (P.A.4) were protected from the weather by a thin sheet of celluloid. To reduce the risk of theft or defacement, a thin, central crosspiece was included in a new design of collection plate holder.
An original proof for the collection plate produced for the box installed outside London G.P.O. EC.1 was found in the archive; this was chosen for the reproduced design. (Some readers will recall this site as being outside the original National Postal Museum in King Edward Street, London.) A good match for the off-white card of the original collection plates was sourced from The Paper Mill Shop. This was printed in the correct blue print that again reflected the adoption of the colour blue for much of the advertising material associated with the airmail service in the 1930s.
About this time, problems arose with the production of the replica enamel signs. Stocksigns admitted defeat with the curved sign as the necessary skills for producing such times has sadly declined in recent times. Difficulty was also experienced by their graphics team tasked with replicating the font used on the original design. This was based on Trajan Roman characters. Additional photographs and advice was provided by BPMA and a good match was subsequently produced. Text was in bright white and an accurate colour match for the base colour of the sign was found within the Stocksigns portfolio: Pantone Blue 072C (reference 93.SC.451/263B). This is somewhat darker than the paint applied to the pillar box but remains correct for the time.
An alternative approach was taken with the curved enamel notice. Despite some deterioration having occurred to the notice over the years, this was by no means as extensive as that which had occurred to the oval sign above the box. Therefore the decision was taken to bring forward the conservation of the original curved sign. It would be protected from future decay and refitted to the box. It was retrieved and a specialised enamels conservator from Plowden & Smith Ltd. was engaged to carry out conservation work. Friable corrosion was removed with a scalpel, glass brush and fine garriflex. Curator antiquing liquid was applied to even out the colour and a layer of microcrystalline wax was applied.
SP171 Airmail 'flag'. Images show condition prior to, the second following, conservation work. (Images: Plowden and Smith Limited)
Cleaned and original escutcheon and collection tablet holders were refitted together with a contemporary enamel tablet from the BPMA collection. Hinges were oiled and the cap re-fitted. Finally, the completed oval sign and its newly painted frame were bolted to the cap. This completed our restoration of the airmail pillar box. It will be on display at the Guildhall Art Gallery, London until 25th July as part of the exhibition Empire Mail: George V and the GPO.
Box on display at Guildhall Art Gallery
In addition to those companies mentioned above, BPMA were also pleased to receive advice and assistance from Brian Nicks, Arthur Reeder, Nigel Slater and Robert Waite.