Questions and Common Sense Answers: Glass has evolved over the years

Q. I have noticed that the glass in some of my older pieces of furniture and even in some old houses is very wavy and distorted. Is this because the glass is old? Does it deteriorate with time like finishes?

A. Glass is a real strange animal. It is technically a super cooled liquid and like any liquid it will eventually flow. However, in practical terms glass is such a stable liquid that it would take tens of millions of years to detect a flow that would cause the distortion you mentioned. The effect you are seeing in the glass is the result of the production method used in the actual piece of glass itself. Until 1825 virtually all “flat” glass used in windows and furniture (excluding mirrors which is a separate subject) was made using the crown method by spinning a bubble of blown glass until it flattened out. Then it was cut in small pieces to use as window panes. The cylinder method was introduced in the early 1800s which produced a clearer, less distorted glass. This method also used blown glass but it was shaped into a cylinder which was cut on one side when it cooled. It was then reheated and the glass laid itself out in a sheet. This produced a glass with dimple patterns due to its uneven thickness rather than the swirl patterns of the crown glass. Around 1900 flat glass was made by pulling it between two iron rollers. This method accounts for the parallel lines of distortion seen in early 20th century homes and furniture. In 1959 the “float” method was introduced. This method poured molten glass over a bed of liquid tin and produces “fire polished” glass that is essentially distortion free since it is a uniform thickness.

Q. I recently purchased a table that a tag on it marked “Duncan Phyfe.” How can I tell if it is a real Duncan Phyfe or a reproduction?

A. Duncan Phyfe was a Scotsman who came to this country in 1784. His original named was spelled “Fife” but he changed it when he opened his shop in Manhattan around 1792, where he worked until his retirement in 1847. While he is known as one of America’s most famous craftsmen, only 12-16 marked pieces of his are known to exist. He worked in the popular styles of the day ranging from Federal to Regency to Empire and was very much a merchant, working with whatever sold well, as well as being a consummate craftsman. Unfortunately, in 20th century America the name Duncan Phyfe has been attached to almost any piece of furniture that has square or rectangular legs that have a curve to them and are attached to central pedestal. They are even referred to as Duncan Phyfe legs even though every cabinetmaker of his period, and most since, used the form. Since Duncan hasn’t made a piece of furniture for more than 150 years, almost assuredly you have a reproduction unless you acquired the table for a price that has at least five and probably six numbers to the left of the decimal in it. If that were the case you would already know the answer.

Q. My antique pine kitchen table is really taking a beating from my kids. I had it professionally refinished 10 years ago when I bought it but that was before I had children. Now everything that gets dropped on it leaves a dent. Would it help to put a coat of polyurethane or something similar on the top to prevent the scarring?

A. Since you had it professionally refinished it probably has a lacquer finish on it. You should ask the person who did it what the finish is. If it is lacquer or the equivalent, urethane and polyurethane won’t stick to the top surface because of the chemistry difference. In order to get good adhesion the table would have to be stripped and completely refinished. If the existing finish is already urethane, then you have the answer. A hard finish, such as polyurethane or urethane, will not make your soft pine table any harder. It will help in keeping down surface mars and scratches but a heavy object dropped on it will still produce a ding by telegraphing through the finish to the soft wood Either replace the table until the kids grow up a little or, better yet, cherish the dings as character imparted to the table during an irreplaceable period in your family life. Its like the wrinkles and gray hair that parents get.

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