Polishing silver at the museum

by Gaby Kienitz, Head Conservator

In period dramas like Downton Abbey, footmen or maids get the dreadful task of polishing the silver. Culbertson Mansion doesn’t have staff hidden in the basement ready to polish the silver; instead, that work is done in the Conservation Lab at the Indiana State Museum. Here in the Conservation Lab, we don’t think of polishing silver objects as drudgery, because we don’t have to polish the same object more than once every 10 years. How do we get away with it? We have a secret ingredient.

Tarnished silver: a punishment for footmen since time began.

Tarnished silver: a punishment for footmen since time began.

Removing the layers of corrosion on silver objects is entirely done by hand with just de-ionized water, precipitated chalk and small pieces of cotton wadding. Once the corrosion layers are removed, the object is carefully rinsed and dried. All of that is pretty much in keeping with Downton-style polishing. The trick up our sleeve is to apply a lacquer coating onto the freshly polished silver. The lacquer prevents a new layer of corrosion from forming on the silver, sealing the shiny silver from things in the environment that might cause corrosion to form again. Unfortunately, the coating isn’t

With all those stubborn nooks and crannies, we’re lucky it won’t need our attention again for a decade.

With all those stubborn nooks and crannies, we’re lucky it won’t need our attention again for a decade.

strong enough to withstand normal household use; it’s meant for objects that get the “white glove” treatment at museums and historic sites. Our most recent polishing project was this lovely silver coffee urn, which took three pairs of hands and many hours to complete.

So, bring out your silver, try on your British accent, and keep regularly polishing at home. Look for the coffee urn to make its appearance at Culbertson Mansion State Historic Site.

Fake it ‘til you make it

by Gaby Kienitz, Head Conservator

Here in the Conservation Lab we’re pretty serious about artifacts. When we treat an artifact we’re guided by a code of ethics that tells us, among other things, that our actions should not permanently remove, alter or obscure any part of an object. But what happens when vital parts of an artifact are missing? That’s when we fake it, and it’s the point where ethics become really important. We’re not trying to create forgeries or be fraudulent; our goal is to stabilize the artifact without creating visual distractions. Sometimes it’s more work than using original materials.

We recently had to “fake it” while treating losses on an early 19th century beehive. The hive is made of coils of straw bound together with flattened sapling “stitches.” Along a section of the lower edge, the sapling stitches were broken with part of each stitch missing and some of the original straw also missing (figure 1). We couldn’t use new saplings to stitch the straw back in place because then we would have to remove the original bit of sapling stitch remaining in each stitch hole, and we didn’t want to use new straw to replace the losses because it might be mistaken for the original.

Fake straw was made by cutting thin strips of Japanese tissue paper, wetting the strips, twisting them in to shape and drying them under tension. We made about 100 pieces of fake straw. After drying, the fake straw was adhered to the broken ends of the original straw along the outer edge of the coil. Additional fake straw was simply inserted into the core of the coil to provide bulk and approximate the original size of the coil. In Figure 2, you can see that some of the fake straw has been attached, and some is still on the table. Strips of sanded polyester film were adhered to the remaining pieces of sapling stitches to secure all of the original and fake straw into the shape of a coil.

The strips of sanded polyester film holding the coil together were disguised by small pieces of two-ply mat board that were cut and painted to match the appearance of the original sapling stitches. They were then adhered to the surface of the polyester film. In the close-up of Figure 3, you can see original straw and an original sapling stitch on the left and to the right is the fake straw and several fake sapling stitches.

When complete (figure 4), the strips of fake saplings stabilized the original straw to prevent additional loss of straw, and the fake straw gives the correct shape and support for the damaged coil. Once upright again, the beehive was ready for exhibition (figure 5). You can see the beehive in person in our Level 2 galleries.

Witch’s Brew

by Gaby Kienitz, Head Conservator

Conservators have all the trappings of a magical enterprise — a stock of arcane ingredients, “potions” that we mix up ourselves, tongue twisting phrases that we use and transformative powers on objects. Don’t believe me? Well, I might not have eye of newt or puppy dog tails, but I sometimes clean an object with my own spit; I’ve used things like fish skin glue and lamb intestine for repairs; and I regularly use an ethyl methacrylate methyl acrylate copolymer.

A cast iron tea pot before (above) and after (below) Gaby works her magic.

In order for the “magic” (a.k.a. work) to happen, a conservation lab needs lots and lots of ingredients and tools. There is such a huge variety of objects that come through the lab with such a range of problems, that a certain treatment might be performed only occasionally and thus only a small amount of a certain supply is needed. Sourcing just a little of these supplies can be a challenge. Imagine my dismay when I was missing a few milliliters of one crucial ingredient for the solution needed to treat a collection of cast iron cookware and fire dogs from Corydon Capitol State Historic Site that had been damaged by water leaking from a chimney. My magic wand was broken!

The ingredient I needed — phosphoric acid — is so common that I couldn’t imagine not finding it sold locally. It’s what gives some colas the “bright” taste, it’s a homeopathic medicine, brewers and hydroponic gardeners use it to lower the pH of their mash and water respectively, it can be used as a flux for soldering metals, and it’s used as a rust and hard water scale remover. Everyone I called either didn’t have it or didn’t have it in the pure form that I needed. It was hard to fathom that I would need to have it shipped from elsewhere, like a rare and precious commodity.

Fire dogs before (above) and after (below) conservation.

Just as I was about to give up, Tuxedo Park Brewers Supply came to the rescue with what I needed. I’m used to buying supplies from some interesting places, but theirs is at the top of my list. Their shop exterior is a brightly painted scene of orange and yellow wheat fields with a bright blue sky that you can only find by going down an otherwise drab, nondescript alley in Fountain Square. Yes, that’s right, their storefront is the alley.

This was a simple potion that I mixed for the treatment of the corroded cast iron, just some tannic acid and phosphoric acid. Tannic acid is a product that has been used since ancient times for making inks, in fabric dyeing and leather processing; it occurs naturally in tree galls, the bark of some trees and in tea leaves. It sounds scary, but it comes in the form of a fluffy, tan colored powder. Luckily, I had a whole bottle of tannic acid powder and once I mixed that with some de-ionized water, added a few drops of the phosphoric acid and heated it up, it was ready to be applied onto the surface with hog hair brushes. Through the magic of chemistry, the rust is converted to a stable, black colored corrosion layer. You can see for yourself what a few ingredients can do to change the appearance of some frightening looking objects. If you want to see them in person, you’ll have to visit Corydon Capitol State Historic Site.