Preserving Cannons

On a few occasions folks have asked me about preserving and restoring Civil War cannons. While I do spend a lot of time looking and studying the guns, about the only first hand experience I have maintaining the pieces is during my limited years of reenacting. Several reenacting outfits use and maintain authentic field pieces. For some time a crew based out of Memphis, representing Bankhead’s Tennessee Battery, used an authentic Noble Brothers Iron 6-pdr, for instance. On several occasions, I was able to look the gun over and found it well maintained. The reenactors are justly proud of the gun and treat it accordingly.

Trouble is most of the Civil War era guns out there are static displays.  While some are protected indoors, the majority are outdoors on the battlefields, cemeteries, and town squares.  Without routine care, iron rusts and bronze corrodes.   In a number of cases the damage done has removed markings that otherwise might offer some sign of the weapon’s past.   So what can be done?

Well, John Morris, an acquaintance of mine through the Company of Military Historians, studied the issue in detail over the years.  Last year he highlighted the problem in his multi part video series touring the Washington Navy Yard’s Leutze Park.

There are several alternatives to simply letting nature take its course, and the pieces simply corroding away.  Certainly moving the artifact indoors to a controlled environment is the best option, but is rarely practical.  John offered up other alternatives based on surveys of weapons currently on display.  First, simple application of paint is perhaps the age-old solution for the problem.  Even bronze weathers well under paint.  Some US Army installations use a clear acrylic paint to allow the natural metal color to show through.

But the paint must be applied well and provide a good seal.  Otherwise moisture between the paint and the surface promotes corrosion.  The bore and all surfaces must have paint applied for the treatment to work properly.  And for Civil War era guns, the vent must be plugged.

One might thing polishing would do some good to a bronze piece.  Trouble is the corrosion on bronze is that familiar green patina.  Recall the 1980’s restoration of the Statue of Liberty, in which most of the external cooper skin panels were not treated or polished.  Although thin (0.005 inch thickness), the patina was part of the metal’s crystalline structure or what I’d call the “fabric.”  Removing even that thin layer by way of polishing will both damage the natural layering of the metal and expose the metal underneath to more corrosion.

Such happened to a 12-pdr Napoleon recently undergoing restoration.  The piece, covered with an oil-based paint for many years, suffered from the elements as the paint deteriorated.  During restoration, the customer required polishing of the gun.  Yes, the gun looks impressive when polished up as if back in service.  The gun must be maintained in that condition now, lest 50 years it need another restoration.  Or perhaps a good coat of clear acrylic paint is on order for the gun.

Certainly the corrosion problem is not unique to Civil War era pieces.  There are scores of Colonial-era, Revolutionary War, and more modern weapons on display around the country.   More than just lumps of metal, these are artifacts demonstrating history in three dimensions.  Would be a shame to lose one for want of a coat of paint.

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