Here is some info on the subject of humidity and the use of Dampits.
On the Topic of Humidification
By Barrie Kolstein
It is once again that time of the year, that with the leaves falling, the temperatures and humidity is falling as well. Thus, it is imperative to bring out the humidifiers and activate them to protect your string instruments.
With the difficult winter weather soon to affect us all, this article deals with information to address the potentially damaging climatic conditions that can adversely affect the structural integrity of all musical instruments.
Whatever the season, protecting your instrument from damage by adverse climate conditions is a challenge for all bass players. Barrie Kolstein gives some tips
In the thirty-plus years that I have been involved in professional instrument repair, the winter 2002/3 season proved to be one of the most difficult for vintage and contemporary basses I have ever encountered. This observation is based upon an extremely high incidence of damage occurring in the form of simple seam openings, top table saddle cracks and extensive top and back area cracks. Such damage has not been restricted to newer instruments, but has affected older, quality basses as well. What makes this situation more perplexing is that so many of these older instruments have not displayed any form of damage in years past. Why this unusual behaviour?
A combination of harsh environmental conditions and innocent negligence on the part of the player by not taking proper precautions caused many of these problems to surface.
Humidity, temperature and general radical climatic changes are the most detrimental and high-risk factors where basses are concerned. However, exposure to extreme or significant changes in temperatures is a straightforward topic to address, and correcting negative situations is straightforward. Leaving the instrument in an unheated area In the winter or an untempered area in the summer is to be avoided. Even on a beautiful spring day with an apparently pleasant climate, a locked car can expose a bass to temperatures high enough to damage the instrument. Keep in mind that good quality basses are constructed with water-soluble glues that soften and loosen their tensile strength when exposed to heat. Thus, logically, the ungluing of a bass bar or crossbar (on a flatback designed bass), opening of a seam, or the re-emergence of a previously repaired crack are all potential risks. Exposure to a colder, dryer environment can also produce similar types of damage as a result of the expansion and contraction of woods and the drying out of water soluble glue even in older, seasoned instruments.
The key is to avoid extreme temperatures for prolonged periods of time. A good padded bass cover can afford your instrument what is termed thermal dissipation. This is the gradual cooling and heating up of the bass so as to manage the effects of radical temperature changes, such as leaving a heated environment for a colder temperature outside, or vice versa.
Humidity control is a bit more complex and can be approached in several ways. Cold and dry conditions, as well as hot humid environments pose risks to an instrument. Temperatures do not have to be extreme for the percentage humidity to drop to a level which could affect the structural integrity of your instrument. In fact, a good rule of thumb is that when the heat is turned on in winter, so should an automatic regime of humidification. This schedule should be adhered to until the winter heating season ends and the warmer spring and summer weather prevails.
A great preventative measure is to monitor environmental humidity conditions using a hygrometer (See Photo Above). This fairly inexpensive device gives a good indication of the percentage of humidity in the space where the bass will be stored. I recommend as a guideline, maintaining healthy humidity levels of a minimum of 40 per cent or better. An ideal level is 45 to 55 per cent Â and a room humidifier should handle that nicely.
What about internal humidifying devices that are dampened and placed within the f-holes of a bass? I was once one of the largest dealers, selling several of these devices but I no longer advocate them for a number of reasons. I have found that over many years of repairing instruments, too many basses have been severely damaged by humidifying devices that have leaked within the instrument. As with extremes of temperature, water-soluble or animal based glues have a tendency to soften and no longer hold together with their original strength when subjected to direct moisture (not humidification in a normal amount). Secondly, when subjected to prolonged dripping from an internal humidifying device, the lower section of rib at the end block on the back table of the bass can eventually unglue and warp.
Consequently, a costly, extensive restoration results.
Another factor to consider is that humidifying a room or environment will in turn humidify your instrument. It is like filling a bathtub up. A tub doesn’t fill from one end to the other, but rather the entire tub fills at the same rate. Humidity is like that as well. For one part of a room to have a consistent level of humidity, say 50 per cent, the entire room must be humidified at that level. For an internal humidifying device to work efficiently (even if it were not a hazard to the structure of the bass), it would have to maintain the same humidity as the room in which it is kept, which is not possible. Most of the humidity emitted from an internal humidifier will be absorbed by the room itself. It’s easy to get lulled into a false sense of security that these devices are adequately protecting the bass, when this is not the case.
Some better advice is to first invest a little money in a hygrometer which will register the humidity percentage of the room in which you keep your bass. If the humidity is consistently below 40 per cent, buy a reasonable room humidifier. There are obviously no guarantees as to how an instrument will fare in a cold, winter environment, but a humidified environment will certainly give the bass, old or new, a fighting chance of avoiding any serious problems.
This winter I saw a number of damaged instruments in university or college housing, where the bass had been stored in locker, making it impossible to manage overall humidification. In this instance, I suggest a simple solution that must be approached with a good deal of responsibility. Where room humidification is not an option, still use a hygrometer to monitor the environment. Should the humidity level fall below the safe point of 40 percent, then using a fine atomiser spray bottle is a low cost, effective solution. One or two fine mist sprays within each f-hole once or twice a day will emit a good deal of humidity within the body chamber of the bass. Apply this responsibly to avoid pooling or puddling of water within the body of the instrument caused by overdoing the spraying, which can result in the
ungluing of component parts of the interior chamber. Proper misting which emits airborne moisture within the bass will temper the interior environment. This is a straightforward, instant means of limiting a damaging scenario. Constant monitoring during these harsh months is the key. I am often asked “Is too much humidity a problem”, and my stock answer is, “Well, don’t let moss grow on the walls!”
In general, high humidity does not pose any great difficulties to the structural integrity of instruments. However, some common sense during warm periods must apply. One should never leave an instrument in excessively high temperature environment. A great rule of thumb is that any instrument should not be subjected to environmental conditions that you would not wish to be subjected to. In extreme temperatures during summer months, air conditioning will certainly moderate the temperature and humidity for both you and the instrument. Common sense is the key here. Keeping the humidity level stable is a good means of protective maintenance for the bass and has benefits for the player as well.
Spring and Summer will get here eventually!