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HISTORIC BLACK POWDER DISASSEMBLY.pdf

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TECH TALK This issue: Firearms ã Part II 3 Minnesota History Interpreter ã December 1998 MINNESOTA HISTORICAL SOCIETY Introduction Once a condition survey of the firearms collection has been completed, following the suggestions in Part I, the treatment of objects that have been identified in the highest priority category for stabilization can begin. The following article describes the tools and techniques for proper disassembly and outlines procedures for cleaning and stabilization. Cautions
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  TECH TALK  This issue: Firearms ã Part II 3 Minnesota History Interpreter  ã December 1998 INNESOT H ISTORIC L  S OCIETY M INNESOTA  H ISTORICAL  S OCIETY M INNESOT H ISTORIC L  S OCIETY   Introduction Once a condition survey of the firearms collectionhas been completed, following the suggestions in PartI, the treatment of objects that have been identified inthe highest priority category for stabilization canbegin. The following article describes the tools andtechniques for proper disassembly and outlinesprocedures for cleaning and stabilization. Cautions Let me emphasize that this article is ageneral guide, not a substitute for the actualadvice of a qualified professional conservator. Iwould also like to emphasize that older historicfirearm types, such as matchlocks and wheellocks, shouldnotbe disassembled; many of these firearms do not have easily removablescrews and pins. Note, too, that the proceduresdescribed in this article should not be used withhighly ornamented firearms or those withstocks of exotic materials such as ivory andhorn. Extreme care and caution must be applied inthe storage and handling of the solvents and chemicals recommended for the cleaning process. To accommodate the longest barrels, the fumehood should be at least 48 inches wide.If a fumehood is not available, an exhaust fan should beused as a minimal precaution. If engineeringcontrols are non-existent or inadequate, thenrespirators must be provided and usedaccording to the updated federal OccupationalSafety and Health Agency (OSHA) respiratorstandard (29 CFR 1910.134). Both acetone andtoluene are strong organic solvents, so do notbreathe in their vapors. Keep skin exposure toall solvents to a minimum.Smoking must not be permitted in thelaboratory areawhile firearms, or anyother objects, arebeing treated.Materials Safety DataSheets (MSDS) mustbe on file for allchemicals being used.These are available from the distributor andmanufacturer. The Minnesota Pollution ControlAgency (MPCA) and your local county PCA can beconsulted for further details on the safe handling andstorage of flammable solvents. Disassembly and Treatment Procedures The methods and procedures described belowhave been developed through experience with thetreatment of 18th- and 19th-century American andEuropean-made flintlock and percussion weapons,and are applicable to both short- and long-arms.Figure 1 (above) will help the non-conservatorunderstand the terms used throughout this article thatrefer to the object components. Refer to the referencebooks listed in the bibliography for details on specificfirearm models.   Conservation Treatments of Firearms by  Paul Storch Continued on p. 4 Editor’s note: T ECH T ALK is a bimonthly column offeringtechnical assistance on management,preservation and conservation matters thataffect historical societies and museums of allsizes and interests. Comments and suggestionsfor future topics are welcome.  Figure 1 (right)Schematic drawings of  generalized  firearms and components.(Not drawn toscale.)  D r  a w i   n  g b   y P  a u l    S  t  o r  c  h   4 Minnesota History Interpreter  ã December 1998 M INNESOT H ISTORIC L  S OCIETY  T ECH T  ALK  ã Firearms: Part II M INNESOTA  H ISTORICAL  S OCIETY M INNESOT H ISTORIC L  S OCIETY Disassembly Procedure: Removing the Barrel  from the Stock and Disassembling the Lock 1) Removal of stock pins and wedges: Gently tapout pins or wedges with a rawhide or wooden malletand soft metal punch. Figure 2 shows a disassembledsmooth-bore percussion pistol with the applicabletools. Look for evidence of previous removal todetermine to which side of the stock the punchshould be applied.2) Removal of tang screws: Figure 3 (right)demonstrates the correct way to hold thegunsmithing screwdriver. Use a screwdriver head thatfits both the length and width of the screw head.3) Removal of barrel from the stock: Gently pullthe hammer back to the half-cock position to free itfrom the pan or nipple. Turn the weapon over and,starting at the breech end, gently pull the stockupward while grasping the barrel as the barrel restson the table.If the barrel is heavily corroded, it mayadhere to the wood. A steady pressure will usuallyfree it from the stock.4) Removal of lock from the stock: Remove theside screw. Grasp the lock by the hammer and thefront part of the lockplate and gently pull the lockstraight out. Look for previous mends of the lockmortise area and try not to pull these out; however, if they do come out, save them for later repair. 5) Disassembly of the lock: Apply the mainspringvise to the mainspring. Make certain that the hammeris in the fired position, since this releases the tensionon the springs. Let down the hammer slowly bycarefully pressing on the sear, which is the lever nearthe rear of the lock. Remove the remaining parts.6) Removal of the trigger guard and assembly from the stock: When the trigger guard andtrigger assembly are held in with pins, do notremove them. If the trigger assembly is a doubletrigger (set type) mechanism, remove the largespring first. If other stock furniture is pinned tothe stock, do not remove it. Butt plates cansometimes be removed and cleaned, if the screwsholding them in turn easily. I would alsodiscourage you from removing barrel plugs andpercussion nipples from museum firearms,because the probability of damaging a uniqueobject is so high. Re-assembly Re-assembly should proceed in the reverseorder of disassembly. The mainspring on thelock should be replaced after the other lock partsare in place. Place the spring in its properposition, then compress it with the vise and slipthe upper lip into the slot. Make certain it isproperly seated, then remove the vise. Continued on p. 5    Figure 2, above. A disassembled percussion-lock, muzzle-loading “Brown Bess”-type pistol, showing the components and standard tools used in the conservationtreatment of firearms.  P  h  o t  o  g r  a  p  h  b   y P  a u l    S  t  o r  c  h  P  h  o t  o  g r  a  p  h  b   y P  a u l    S  t  o r  c  h   Figure 3, right.This shows thecorrect way toremove a screw from a historic  firearm.  Apply pressure perpendicularlyto the screwhead while turning it.It is importantto maintain this rigid  perpendicular  pressure toavoid strippingthe screwhead.  5 Minnesota History Interpreter  ã December 1998 INNESOT H ISTORIC L  S OCIETY  T ECH T  ALK  ã Firearms: Part II M INNESOTA  H ISTORICAL  S OCIETY M INNESOT H ISTORIC L  S OCIETY Metal Cleaning Degreasing: It is important that the followingoperation take place under a fume hood or with otheradequate ventilation, using the proper gloves. Usingcotton wool and cotton swabs, apply Stoddard’sSolvent, or a similar mineral spirits-type solvent, tothe metal parts. This should also remove surface dirtand some corrosionproducts. Removing ferrous and non-ferrous corrosion: Applya petroleum-based rust andlubrication oil such as WD-40 or the equivalent. Do notuse an oil with silicones orother “permanent”lubricant added. Apply withcotton to both the patinatedand unpatinatedcomponents. A mild steelbrush and very fine steelwool (0000 grade and finer)may be gently used onheavily corroded,unpatinated parts.  Note: Brass brushes andscrapers, contrary tocommon gunsmithingrecommendations, shouldnot be used on exteriorsurfaces; brass is soft enough to leave a yellowmetallic residue on the steel surfaces. Be careful toremove only the corrosion and not the patinationlayer. Avoid touching engraved and stamped areaswith abrasive tools. Do not clean brass and silver partsuntil they shine. Remove the cleaning oil with acetoneor mineral spirits; do not leave the oil on the parts as acoating. Following these steps may not remove all thecorrosion, but it is good for first-level cleaning andstabilization. A conservator should be consulted formore difficult corrosion problems. Cleaning barrel interiors: While holding thebarrel over a solvent-resistant container, pour mineralspirits into the muzzle end. Discard dirty solvent inan approved container; do not pour down the drain.Secure the barrel in padded vises and clean it, using abrush of the proper caliber on the cleaning rod. Rinseout the barrel with solvent after each brushing, untilthe cotton patch comes out relatively clean. Finally,apply a liberal amount of rust inhibiting grease (called“RIG,” sulfonated petroleum jelly) down the entirelength of the barrel on a clean patch. Coating metal parts: The best coatings to use arethe Acryloid series of acrylic resins (Rohm and Haas;available from conservation supply distributors).Acryloid B-48N was formulated specifically for useon clean metal surfaces. Incralac is a similar polymerto B-48N, with the addition of a copper corrosioninhibitor. Both of these are soluble in toluene andxylene. Use a good quality natural bristle brush.Allow the parts to dry thoroughly before re-assembly.Reapply a small amount of coating to the screw headsafter re-assembly. Coat the stock furniture beforecleaning the stock. Re-label the firearm: Refer to Part I of this articlefor a discussion of proper labeling procedures. Cleaning the Wood  Removal of dirt and corrosion from the interior of the stock: Use Stoddards or mineral spirits on swabs.Do not soak the wood. Consult a conservator if insectdamage or major breaks are found. Cleaning the exterior: Use a mild soap, such asMurphy’s Oil or Vulpex (available from conservationsupply distributors) in distilled or de-ionized water ata dilution of 2-3 percent. Do not soak the wood. Wipewith a damp cloth after the soap application, then drywith a clean cloth. Consult a conservator if the finishis delaminating, water spotted, or needs other moreinvolved treatment beyond simple cleaning. Protective coating: Apply a good quality pastewax (without silicones) to the exterior surfaces of thewood. Petroleum-based microcrystalline waxes such Continued on p. 6   Figure 4a,right, above: Fire-damaged  forestock. Thewood is friableand fragile.  Figure 4b,right, below: Forestock after treatment bythe author withconsolidantsand epoxy putty.    P  h  o t  o  g r  a  p  h  s  b   y P  a u l    S  t  o r  c  h  , c  o u r  t  e s   y o  f   U  p   p  e r  M i   d  w e s  t  C o n s  e r  v a t  i   o n A s  s  o c  i   a t  i   o n  6 Minnesota History Interpreter  ã December 1998 M INNESOT H ISTORIC L  S OCIETY M INNESOTA  H ISTORICAL  S OCIETY M INNESOT H ISTORIC L  S OCIETY   T ECH T  ALK  ã Firearms: Part II as Renaissance brand (available from archival andconservation supply distributors) or natural carnaubawax brands such as Butchers or Trewax areacceptable. The carnauba waxes are in turpentine.Follow the manufacturers application instructionscarefully. Avoid waxing checkered areas of the wristand forestock grip because wax makes it difficult tobuff indentations and will dry to a light color, whichis very visible. Other Levels of Treatments It is important to know what should not be doneto a historic firearm, and when the problem excedesyour skills and resources. Firearms that have beendamaged by fire and/or water should be examined bya conservator prior to disassembly and cleaning. Theuse of epoxies or any other fillers or adhesives mustbe avoided except when applied by an experiencedconservator and their use is warranted bythe condition of the object. (See figures 4a and 4b.)The procedures described above will clean andstabilize historic firearms with the minimumalteration of the srcinal materials. Do not attempt to “rebuild” parts, makereplacement parts, or drastically alter the nature of theobject by polishing or refinishing. There are caseswhen those operations may be performed, but otherissues must be taken into account before they areapplied. (See figures 5a and 5b.)Always document each step of your treatmentcarefully with both photographs and written records.Note any special problems that arise during thetreatment of the object. If followed carefully, theseprocedures should preserve both the historical andaesthetic value of a museum firearms collection. Remember: Proper storage of firearms is also anessential part of preventive conservation. The firearmsshould be protected from dust and should be checkedregularly for the recurrence of interior or exteriorcorrosion. Refer to Part I of this article for a morecomplete discussion of this topic. F URTHER R EADING The current Track of the Wolf, Inc. catalog has anextensive offering of books on the history andmanufacture of historic firearms, and is also a goodresource on the parts of the mechanisms:Edition 14-D, 1998-2000; Track of the Wolf, Inc.; P.O.Box 6, Osseo, MN 55369-0006McCann, Michael, “Respirators,” in  Art Hazards News, Vol. 22, No. 3, 1998, New York.Fadala, S. and D. Storey, Black Powder HobbyGunsmithing, Northbrook, Ill., DBI Books, Inc.,1994.Prytulak, G., “Threaded Fasteners in Metal Artifacts,” CCI Technical Bulletin No. 17, CanadianConservation Institute, Ottawa, Canada, 1997.Storch, P. S., “Care and Handling of Firearms Part II:Disassembly and Cleaning,” in Conservation Notes No. 9, August 1984, Texas MemorialMuseum, University of Texas at Austin, Texas.White, P. R., “The Care and Preservation of Firearms,” CCI Technical Bulletin No. 16, Canadian Conservation Institute, Ottawa,Canada, 1995.  Paul Storch has been objects conservator in theDaniels Objects Conservation Laboratory at theMinnesota Historical Society since January 1991.He is a frequent contributor to The Interpreter. Phone: 651/297-5774; e-mail: paul.storch@mnhs.org  P  h  o t  o  g r  a  p  h  s  b   y P  a u l    S  t  o r  c  h  ;  c  o u r  t  e s   y o  f   t  h  e U  p   p  e r  M i   d  w e s  t  C o n s  e r  v a t  i   o n A s  s  o c  i   a t  i   o n  Figure 5a, above: Exterior of percussion lock after re-browning and replacement of the hammer and hammer screw. Treatment by the author; thesrcinal tumbler was damaged. Figure 5b, immediately above: Interior view of lock, showing replacementtumbler and assembly modification.
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