All About Open Seams
Has your instrument sounded a bit more dull while playing it? Do you notice a buzzing sound? You might have an open seam!
What is an open seam? An open seam is a separation of either the top or back plates from the rib of the instrument. Some are small and others can be quite large. If you think your instrument might have an open seam, go ahead and look at where the plates meet the ribs and check for gaps. To check for smaller seams, you can shine a bright light along the seams on the outside of the instrument, while looking through the f-holes to see if light is breaking through at any points.
Why do open seams form? First of all, open seams are a good thing depending on how you look at it. String instruments are held together by flexible hide glue. When experiencing temperature and humidity changes–specifically humid to dry and hot to cold–this allows some of the parts to shift instead of fracturing the top and back plates. If this were not done by design, you could risk expensive repairs and decreasing instrument value. This way, the repairs are simple, quick, and inexpensive while protecting the vital parts of the instrument.
How can you prevent future open seams? You can keep your instrument in parts of the house that are temperature controlled, humidify the area(s) where the instrument is stored, and use an instrument humidifier for travel in dry climates. Wooden instruments are happiest when kept in temperatures between 60-75℉ and 35-50% humidity. As mentioned before, open seams are a normal part of owning a string instrument and are easily repaired.
How are open seams repaired? The luthier separates the section of rib where the seam is located, folds it back into place, and uses special clamps to hold it. Then, the luthier alternates between applying hide glue and re-clamping to ensure that the rib shape remains. After that, the instrument is left to sit overnight. It is important to remember to take your instrument to a trained professional who will use the correct materials and processes to ensure the proper care of your instrument.