The percussion pepperbox unearthed at Ballarat

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Aubrey James
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1 In late 1996, plans were drawn up for the development of the Eureka Discovery Centre in the City of Ballarat. Heritage Victoria required that an archaeologist be engaged during the works to monitor any significant archaeological deposits that might be exposed. Archaeological investigations were carried out at the Eureka Precinct site by Dr Vincent Clark between December 1996 and mid A number of archaeological artefacts and features were uncovered during the works, including an abandoned mineshaft. The archaeologist recovered an assortment of artefacts from the mineshaft including a small percussion type revolver. Although corroded and heavily concreted, the firearm was identified as a pepperbox pistol. This report details the conservation treatment undertaken on the pistol by Barbara O Brien (Conservator Heritage Victoria) and Richard Garcia (Conservator Western Australian Maritime Museum) in September Effective primarily as a close quarter self-defence weapon, pepperbox pistols first made their appearance in the late 1830s and were produced mainly for civilian use. They soon achieved popularity because of their multi-shot advantage over single or doublebarrelled pistols, but they had been largely superceded by the mid-1850s (Wilkinson 1977). Pepperbox pistols actually represent one of several stages in the development of the percussion revolver. Generally, the term revolver is only applied to a gun with a single barrel and rotating cylinder, and a multi-barrelled, rotating firearm of the same general type is known as a pepperbox pistol (Boothroyd 1970). Some early models had four or six barrels that had to be rotated manually, but mechanisms had developed to the stage whereby pressure on the trigger caused the barrels to rotate by the 1840s. (Anon, 2004) The percussion pepperbox unearthed at Ballarat is of a common type, being of the self-cocking, bar hammer, six-barrelled variety, and comprises a number of component parts made from metal and wood (Figure 1). The solid cylinder of metal, machined from a single block of steel, features 6 bores or barrels, known as the barrel group (A), and is mounted on a rod (B) that screws into the standing breech (L) on the frame, located beneath the hammer (F). The barrel group rotates around the rod and is secured to it by one pan-headed screw at the muzzle end. The barrel group rotates in an anti-clockwise direction by virtue of a pawl and ratchet system. This refers to a pivoted bar adapted to engage and move the indexed, star-shaped machining at the rear of the barrel group when the trigger (D) is pulled back. The bar hammer (F) is of a standard, double-action or self-cocking type, which means that pulling the trigger not only cocked the hammer, but allowed it to fall in a striking action. The frame (H), which is a single forging, houses the inner spring components (I) and (J) as well as the trigger

The dimensions and specifications of the pistol, as determined during treatment, are as follows: length: 210 mm long width: 40 mm wide height: 90mm high bore of barrel: 0.325 or 0.

2 the percussion cap, sending a powerful flash down the vent, causing the weapon to fire. The barrel assembly was subsequently turned to bring the next bore into line and the procedure was repeated (Hogg 1975, Wilkinson 1977). The dimensions and specifications of the pistol, as determined during treatment, are as follows: length: 210 mm long width: 40 mm wide height: 90mm high bore of barrel: or 0.32 calibre threaded locating screw: BSF (British Standard Fine) thread 24 tpi (threads per inch) with outside diameter dimension of 0.29 weight (after initial treatment): 593.7g. and hammer working mechanisms (G). The working mechanisms are covered with side plates, often engraved. Two curved, wooden panels are fixed to the frame via a threaded, steel, circular head screw (with sleeve) and hexagonal nut system (K) to form the handle grip. At the end of each barrel and set at right angles to it is a nipple or vent hole (C), which communicates with each bore. During firing, each nipple was fitted with a small metal percussion cap. The nipples are partially covered by a close fitting shield, which extends forward from the breech and side plates, and functioned to prevent the percussion caps from being brushed or shaken off (Myatt 1981). To fire the weapon, each barrel was muzzleloaded with detonating powder and ball (and possibly wadding), after which the percussion cap with explosive was placed over each nipple. The trigger was pulled, causing the hammer to drop. This hit For stabilisation purposes, the pistol was placed in a sealed container in cold storage at Heritage Victoria Conservation laboratory. During this time, it was sprayed every few weeks with 30% isopropyl alcohol in distilled water to prevent mould growth and to keep the materials moist. From July 1999, it was displayed (again in cold storage) at the Eureka Stockade Discovery Centre until funding became available for its conservation in April When examined, the pistol was still muddy and damp. It appeared intact, with all surfaces showing heavy concretions, rust and pebble/soil residues. Concretions were visible in all barrels with one bore almost completely occluded. Similarly, all the nipples were covered with hardened soil residues. The grooves between the barrels are often stamped with a view or proof mark (Myatt 1981) but due to the corroded metal surface on the cylinder, no marks could be identified at the preliminary or later stages of conservation. Likewise, only faintly discernible markings were evident on the side plates, although images of pepperboxes often demonstrate elaborate engraving. In the absence of engraving and maker s marks, the maker and date of manufacture of this pistol, like many percussion pepperboxes of English provenance, is difficult to ascertain (Boothroyd 1970). The trigger guard and curved trigger were joined

The aim of conservation treatment was to remove the concretions to enable better visualisation of the pistol, and to facilitate dismantling so that appropriate treatments for the various metal and

To this end, the pistol was transported to Western Australia Maritime Museum Conservation Laboratory and a collaborative conservation treatment was undertaken by Barbara O Brien and Richard Garcia,

3 The aim of conservation treatment was to remove the concretions to enable better visualisation of the pistol, and to facilitate dismantling so that appropriate treatments for the various metal and wood components could be effected if required. To this end, the pistol was transported to Western Australia Maritime Museum Conservation Laboratory and a collaborative conservation treatment was undertaken by Barbara O Brien and Richard Garcia, the latter having extensive experience in the conservation of firearms. together by thick concretions, and the hammer was corroded and fixed to the frame. Exposed metal on the frame generally showed pitting and losses, while areas of thin metal, such as the nipple shield and trigger, appeared quite fragile (Figures 2 & 3). The curved, wooden panels, although wet and stained with mud and iron corrosion products, appeared in reasonably sound condition apart from surface abrasions and losses along the edges. The screw and nut assembly joining the wooden handle grips to the frame showed extensive corrosion and was immovable. Visualisation of the inner components was not possible prior to conservation treatment; however, preliminary radiographs from 1997 revealed that the main spring located within the handle had been fractured whereas the other springs appeared to be intact. X-rays were taken again in 2003 but no discernable differences or changes in condition could be detected (Refer Figures 4 & 5). Initially, the focus was on removing soil and concretions from the steel surface of the barrel. Gradual removal of the concretions was effected through a combination of controlled heat application (via the tip of flame from an oxy-acetylene torch) to the wetted out metal surface, and mechanical cleaning utilising fine dental tools and wooden skewers. The pistol was kept wet throughout to facilitate the process as well as ensuring that the metal was not overheated. Eventually, the form of the grooves between the barrels became more clearly marked. The metal surface itself was quite pitted with losses due to corrosion gradually becoming apparent. Maker s marks were not visualised. The metal side plates were treated in a similar fashion; however, only faint lines and marks of engraving could be observed. Periodically, WD-40 lubricant was sprayed into the bores and around the hammer and nipples to soften corrosion products. After this, slow mechanical cleaning, using fine dental tools, was undertaken to expose the nipples beneath the shield and the space between the barrel group and the breech. It became apparent that the nipples were occluded with concretions also. Eventually, it was possible to rotate the barrel group and rod on its thread, and remove it from the breech for further cleaning. This created better access for more effective de-concretion and cleaning of the thread, inner star-shaped machining and bores.

Debris within the bores was removed by slowly hand-twisting an appropriate sized drill bit into the bore, removing the bit and repeating the procedure with regular applications of lubricant.

4 Debris within the bores was removed by slowly hand-twisting an appropriate sized drill bit into the bore, removing the bit and repeating the procedure with regular applications of lubricant. Once softened, a final clean of the bore chambers was achieved using lubricant and fine bore, nylon brushes. In the completely occluded bore, a small portion of metal from the wall of the barrel was lost when attempting to remove the last of the concretion. Given the perceived fragility of the steel in this area of the barrel group, no attempt has been made to remove the fine concretion attaching the barrel group to the rod. On a smaller scale, the communication between each nipple and bore was also re-established through mechanical cleaning, utilising tiny drills twisted by hand and lubrication with WD-40. In order to dismantle and treat the rest of the pistol components, it was necessary to remove the wooden handle grips from the steel frame; this posed quite a difficult problem. Not only were there resistant soil residues and pebbles covering the frame and the edges of the handle grips, the screw and nut fastening them to the frame were highly corroded and their outlines virtually obscured with concretion. Edges of the wood were also obscured. To help soften the residues, the pistol was immersed periodically in an ultrasonic bath of tap water. This process, combined with mechanical cleaning and heat application to the metal (using a provisional heat shield of wet cloth over the wooden components), facilitated the separation of the bulk of concretions from all surfaces. It was then possible to visualise the join between the wooden handle and steel frame, and this was carefully delineated using dental tools. Due to poor access and the fact that concretions on the screw thread and nut were so extensive, it was not possible to undo the screw and remove the handle grips by conventional means. One approach was to sacrifice the screw by drilling off the head, but this would have meant leaving the pistol disassembled or using a replacement screw to reattach the handles. It was felt to be important to preserve the integrity of the object by retaining all original components where possible. It was decided, therefore, to explore alternative approaches. Some movement of the wooden handle grips could be achieved by manoeuvring the screw back and forth, and eventually one of the grips loosened up sufficiently and was eased away from its contact with the metal frame. This allowed a fine hacksaw blade to be passed between the wooden grip and the metal frame, and the screw was then cut in half and the handle components carefully separated. Examination showed the wood to be in remarkably sound, solid condition apart from external surface abrasions and staining from iron corrosion products. It did not appear deteriorated, moist or spongy. It was decided, therefore, to coat the wooden handles with wax and monitor them for any dimensional changes, at least in the short term. Examination also revealed the fracture in the steel main spring, previously viewed in radiographs, as well as two corroded remnants of the trigger spring, which were found loose within the handle. As a matter of conjecture, it is possible that transport, handling or even treatment in the ultrasonic bath may have resulted in fracture of the corroded screw holding the trigger spring to the frame. The small spring attached to the pawl and ratchet system appeared intact and sound. The fine trigger and hammer components were filled with a combination of moist and hardened soil residues. Again, a combination of mechanical cleaning methods and lubrication with WD-40 enabled the removal of most of the concretions and the loosening of working parts, such as the hammer. The trigger components, and pawl and ratchet system were deemed too fragile to endure much in the way of mechanical cleaning and these were left untouched after removal of most of the softened concretions using a brush and water. All metal surfaces were then degreased using acetone. The trigger spring components were repositioned and re-adhered using an acrylic resin adhesive (30% w/v Paraloid B-72 in acetone) as it was felt appropriate to retain all components in as near as possible to original positions, and prevent loose components rattling around and possibly causing further damage (Refer Figure 6).

over with petroleum spirits (120 160 C) to remove as much microcrystalline wax as possible.

in purified water. The handles were then blotted and placed in a freezer at -20oC for drying until stable weights were achieved.

5 over with petroleum spirits ( C) to remove as much microcrystalline wax as possible. Over several months, the handles were placed in increasing concentrations (10 40 % w/v) of PEG 400 (polyethylene glycol) in purified water, followed by impregnation in a solution of 50% w/v PEG 3350 in purified water. The handles were then blotted and placed in a freezer at -20oC for drying until stable weights were achieved. Once impregnation was complete, excess PEG residues were removed mechanically and the pistol was reassembled using a barrier of Mylar sheet between the wood handles and metal frame to protect the latter from the slight acidity of the PEG (Refer Figures 7 and 8). Likewise, the broken ends of the main spring were re-adhered using 30% w/v Paraloid B-72 in acetone, to stabilise the spring components and prevent undue movement, and a pad of Ethafoamâ was also placed beneath it for support. The two halves of the screw were welded together, the nut removed and the threads cleaned using WD-40, heat and wire brushes. Both wooden handle grips and metal components were coated with Beckett s microcrystalline wax in white spirits on all surfaces. The handle was then reassembled with the repaired screw and the various components of the pistol reassembled. Finally, a custom-made box using archival materials was fabricated for handling and support. The pistol was returned to the Heritage Victoria Conservation laboratory in early October. After several weeks, it was noted that, despite being in an environmentally controlled storage area, the wooden handles were beginning to show signs of shrinkage. The screw and nut assembly were duly dismantled and the wooden handle grips removed and wiped The aim of treatment had been to clean and remove concretions from the pistol in order to facilitate examination, stabilisation and improvement its overall appearance. In addition, it was hoped the pistol could be dismantled to allow investigation and treatment of internal components, and this was successfully achieved through a collaborative approach between two conservation facilities. In conclusion, although some components remain concreted due to their fragility, the pistol generally appears stable and will continue to be monitored. Anon Perrins pepperbox will return to city < thisisworcestershire.co.uk/2004/3/28/ html> Newsquest Media Group 2004 Boothroyd, G The Handgun, Bonanza Books, New York. Hogg, I The Illustrated Encyclopedia of Firearms, Hamlyn Publishing Group, London. Myatt, F An Illustrated Guide to Pistols & Revolvers, Lansdowne Press, London. Wilkinson, F The World s Great Guns, Hamlyn Publishing Group, London. Barbara O Brien (author to which correspondence should be addressed) is an objects conservator at Heritage Victoria Conservation Laboratory, <barbara.o brien@dse.vic.gov.au>. Richard Garcia is the Manager of Technological Materials at Western Australia Museum, where he has worked for 28 years. He has a diploma in mechanical engineering and specialises in treatment, including flame cleaning, of all types of technical objects, including firearms. <Richard.Garcia@museum.wa.gov.au>

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