While this iron axe head from the Russian period is pitted, it has a compact dark patina and is currently stable.
Photo credit: Alaska State Museum collection III-R-115
This shipwreck item is severely rusting with large pieces spalling off the surface, powdering, and crumbling. Maritime and archaeological iron is often contaminated with salts that exacerbate corrosion and deterioration.
Photo credit: Alaska State Museum collection III-O-290
This rusty iron wok also has spalling and powdery surfaces, and has some pitting in the area closer to the rim.
Photo credit: Alaska State Museum collection 2000-4-1
This artwork is deeply pitted by design, although the vivid orange can sometimes indicate active corrosion. Orange and rust-colored corrosion indicate the presence of iron. If you’re not sure the item is iron, a magnet can be helpful.
Photo credit: Alaska State Museum collection 2008-40-1
These boom chains used for logging show two common surface appearances for stable iron. The one on the left has a slightly blacker surface from a tannic acid treatment. The one on the right has not been chemically treated but simply cleaned.
Photo credit: Alaska State Museum collection 2015-25-1
Many historic collections contain enamelware dishes and kitchen items. Where the enamel is chipped, there is often rust. Here it can be seen along the base, the rim, and at the attachment point of the handle. This might be described as “minor disfigurement” since it would still look nice on exhibit.
Photo credit: Alaska State Museum collection III-O-946
These tree climbing spurs used by loggers are rusted, missing a strap, and the strap that is present is brittle and cracked. The term “relic condition” in the report can indicate that these are in overall poor condition for many reasons but still have historical interest.
Photo credit: Alaska State Museum collection 90-25-1
The surface of this firearm is spalling and has many small areas of loss. There are also marking which are well worth photographing for the documentation. But don’t miss the smears of paint that capture someone’s fingerprints. Whose fingerprints are they? The soldier? A later collector? We don’t know, but it adds a personal, human dimension to the artifact and ought to be noted.
Photo credit: Alaska State Museum collection III-O-183
When the paint layer on metal loses its integrity, it can start to lift, bubble, and flake. This can be exacerbated by poor handling. In this case, paint loss is associated with rust. Also, this object is dirt and dusty. Cleaning it will risk causing further damage to the paint layer, but dirt and dust are hygroscopic, holding moisture, and can promote corrosion. What to do next is a tricky matter, but the first step is good condition documentation.
Photo credit: Alaska State Museum collection 2000-4-42
The presence of green corrosion is usually an indicator that there is a copper resent. Severe corrosion where two different metals meet can be an indicator of galvanic corrosion.
Photo credit: Ellen Carrlee
The waxy green crust under the metal and the leather is probably a copper stearate or a copper oleate, and the result of the oils in the leather reacting with the copper in the metal. Typically, is does not do much damage to either material but it can cause green staining.
Photo credit: Alaska State Museum collection 2005-9-34
The white substance in this engraved copper spoon is probably the remnants of a polishing compound.
Photo credit: Alaska State Museum collection II-B-1007
XRF indicates the main metal in this ring is zinc, so the powdery white seen here is likely zinc corrosion.
Photo credit: Alaska State Museum conservation research collection
The hands of this model kayaker were made from lead, and the powdery white corrosion seen here is typical of lead corrosion. Be careful, as this is toxic.
Photo credit: Alaska State Museum collection II-F-272
When copper is contaminated with chlorides, as often happens with maritime or archaeological artifacts, bronze disease can occur. This is not a contagious problem, but is a cyclical and destructive corrosion mechanism caused by the presence of chloride ions, oxygen, and moisture. Bronze disease often appears as a powdery pale green corrosion. The corrosion here is suspicious, but there are tests to confirm it.
Photo credit: Alaska State Museum collection 2008-11-28
Sometimes a metal will show corrosion and it is not clear what kind of metal or alloy it might be. Describe what you see. Here, the snap on this metal pouch is made of a grey metal that has severe white powdery corrosion.
Photo credit: Alaska State Museum collection 75-16-30
This pipe bowl has thick white crusty corrosion products. These might be associated with an accretion or another substance, since they are limited in their location.
Photo credit: Sheldon Jackson Museum collection SJ-II-P-0140
Plated metals often show pitting or losses. Describe these as localized, overall, spotty, or concentrated in certain areas. Are they associated with rust beneath? Do they seem to be wear-related?
Photo credit: Alaska State Museum collection III-O-1034
This elaborate silver punchbowl has a gold wash inside.
Photo credit: Alaska State Museum collection III-O-422
The gold wash is very thin, and is at the verge of being worn through in some places from the bowl being wiped out many times.
Photo credit: Alaska State Museum collection III-O-422
Polished metal is quite reactive, and here an oily thumbprint has etched into the surface. Polishing is usually micro-abrasion and involves small amounts of surface loss each time. There are cases of a silver carver’s signature being nearly worn off a silver bracelet from repeated polishing.
Photo credit: Alaska State Museum collection III-O-422
The planishing marks on the underside of this ladle are starting to show wear, and the gold wash has worn through.
Photo credit: Alaska State Museum collection III-O-423
Natural gold nuggets do not show corrosion, but sometimes the fittings or other hardware on gold jewelry might. This gold watch and chain are in stable condition with no obvious damage.
Photo credit: Alaska State Museum collection III-O-505
This samovar has many component parts. The tray and chimney have very different polishing histories from the rest of the object and are much darker. The extreme shiny surface of the chimney indicates it has been lacquered, which also suggests it was once polished but perhaps the lacquer did not protect the polish after all. In this case, we might suspect the chimney and the tray did not fit in the exhibit case and were not re-polished, perhaps?
Photo credit: Alaska State Museum collection III-R-319
The base of this World War II gas canister shows aluminum corrosion. This could be called a blister of corrosion. Aluminum does not easily corrode, but when it does this kind of blistering and white/ gray power is typical.
Photo credit: Alaska State Museum collection III-O-165
This copper alloy zipper is severely corroded and has suffered the loss of many teeth. The zipper is no longer functional, and the corrosion risks staining the surrounding material. A non-functional zipper might impact how this garment could be exhibited. The remaining teeth are likely to be delicate, and the zipper pull probably cannot be easily repositioned without risking damage to the teeth.
Photo credit: Alaska State Museum collection 2013-61-1
