LIQUID HONING The Ohio Conservation Center recently purchased a liquid honing machine from Vapor Blast Manufacturing Company. The cabinet machine can provide gentle surface cleaning and/or mild polishing of metals using high pressure water and fine media.
It has already proved useful in a variety of situations.
Recently, we tested liquid honing to efficiently remove a complex of dirt, aged shellac and paint coatings from cast bronze plaques. These plaques were originally installed as cast and polished directly from the foundry in a bright bronze with no coatings, and the liquid honing gently returned the test plaques to this condition. This was fortunate as we have 527 of these plaques to clean.
These 527 cast bronze relief plaques were insets in the courtroom doors of the historic E. Barrett Prettyman United States Courthouse in Washington, DC. We are in the process of rebuilding all of these historic doors with new veneer and installing the plaques in a condition replicating their original appearance but with a sense of slight age through light patination as requested by the government.