From: belavoce@ix.netcom.com (Earle White) Newsgroups: alt.guitar Subject: Thermal/Humidity Protection Date: 7 Mar 1995 06:02:13 GMT Since I've noticed numerous postings in this newsgroup concerning thermal and humidity protection for stringed instruments, I'm taking the liberty of posting the following letter I wrote on the subject to Acoustic Guitar magazine. The letter should appear in the May/June '95 issue. There seems to be lots of misunderstandings concerning thermal and humidity control and protection. Hopefully, this letter will clear up the cloud factor, just a little. If you have any questions or comments, my contact info appears at the end of this letter... Best Regards ======================================================================= Editor, Acoustic Guitar Magazine PO Box 767, San Anselmo, CA 94979-0767 Re: Letter for publication in next issue ... Dear Sir: I want to commend Acoustic Guitar and Bob Taylor for the technically excellent article on how humidity affects guitars (September/October 1994). Beyond the usual brief comments, such as "don't put it in your car" or "humidify your instrument in the winter", it is very rare indeed to find any definitive media coverage on the perils that routinely affect guitars and other stringed instruments in the real world. In fact, the leading cause of instrument damage and expensive repairs is exposure to excessive temperature and humidity conditions. Just ask any repair person about cracked and shattered finishes, top crack repairs, bridge reglues, neck resets, and various other re-gluing, straightening, and restoration jobs. He'll probably tell you that, aside from routine maintenance items like refret jobs, as much as 90% of the repair business comes from thermal and humidity abuse. Even the best hardshell case is inadequate protection when an instrument is exposed to rapid changes and extremes of temperature and humidity. Aside from use of synthetic materials, hard shell cases really haven't changed much since the 1800's. Currently available hard shell cases themselves, do not provide adequate thermal or humidity protection to accommodate routine weather changes, much less the exposure that occurs when the instrument is taken outside, or left in a closed automobile or aircraft cargo hold. The reality is that stringed instruments made of various woods, plastics, metals and other dissimilar materials are susceptible to damage from heat or cold, and from excessive dryness or humidity, as evidenced by the thermal/humidity damage present on the vast majority of used and vintage instruments. No matter how much effort the luthier puts into obtaining stabilized tonewoods, de-stressing instrument structures, or developing elasticized finishes, a guitar will eventually show damage due to thermal/humidity exposure unless it is kept in a stable environment. In addition, world class high performance guitars are more susceptible to damage than lesser instruments, due to lighter overall construction, thinner tops, smaller braces, and closer tolerances. Indeed, the finest close-tolerance high performance acoustic guitars of all time are being made right now, by a host of highly-knowledgeable and talented builders using modern tools, close tolerance CNC machining, and superior quality standards. So, will these instruments survive in better shape than their vintage counterparts? Is 1880's case technology going to do the job in today's world? PLAYER AWARENESS IS THE KEY. The answer is: 1.) Stabilize the guitar by buffering thermal and humidity changes; 2.) Use a lab quality (+/- 5% accuracy min.) thermometer/hygrometer in your instrument case to accurately measure the instrument's environment; 3.) Humidify or dehumidify (as appropriate)using water-retentive clay-based humidifiers or tyvec-packaged desiccant packs (respectively) in your instrument case when warranted. So, what about some guidelines? Our lab and real world research suggests: If ambient humidity is 40% or less - humidify your guitar; if humidity is 70% or greater - dehumidify. For safety's sake, strenuously avoid rapid temperature changes (more than 20F per hour), and exposure to temperatures less than 45F or more than 105F. Naturally, individual instruments respond differently to thermal and humidity stress, some being more sensitive (i.e. more easily damaged) than others. In turn, the above limits are meant as a guide only - it's better to be safe than sorry. Also, it is a good idea to let your instrument adapt slowly to significantly different conditions while inside its case - before removing it! If you have old guitars, bear in mind that they may be more susceptible to damage due to the old type glues and finishes, and may also have compromised glue joints due to repeated exposure and aging, hence, more care is indicated. Luckily, most of these older-type glues and finishes were discontinued years ago in favor of stronger, more durable, temperature/humidity-tolerant glues and finishes. By the way, I recommend water-retentive clay humidifiers since they maintain a more constant humidity level than foam, and do not dry out as readily. Tyvec-packaging of desiccant (aka: silica gel) more effectively prevents the powdered material from escaping into your case and onto your guitar’s finish. Desiccant is a silicon-based product roughly similar to glass; therefore, it's definitely something you don't want to breathe or polish into your guitar's lacquer finish. Buffering your instrument from thermal/humidity changes can be a difficult problem. Wrapping blankets or other insulation around the instrument has been done for years, and really does no good since it isn't airtight. Sleeping bags have been used, and do provide some degree of marginal protection -- approximately 2-3 times that of the case itself, depending on the bag rating (polar-rated is better). This approach is certainly better than nothing, but is inconvenient and can be dangerously ineffective. After about 12 years of experimentation, I designed a simple, effective, and inexpensive solution to the problem, namely the ClimateCase case cover. The ClimateCase cover is designed to stabilize wooden instruments, by providing a ported, nearly air/water-tight, and insulated buffer between the instrument and the external environment. It reflects about 90% of heat and sunlight in hot conditions, compared to black hardshell cases that absorb 90% of heat/sunlight. Due to a thermos-bottle type effect, it also retains about 90% of warmth in cold conditions. Overall, it provides over 10 times more thermal protection than a black hardshell case and, because it's nearly air/water-tight, it stabilizes the humidity level inside the instrument case. Of course, it also protects the instrument case from wear and tear, dust, and rain. We have done considerable engineering research into the causes and effects of thermal and humidity exposure on musical instruments over the past 16 years, and would be happy to answer any questions your readers may have on these subjects. Thanks and Best Regards, Earle White (ClimateCase Co.) POB 506, Grass Valley, CA 95945 (916) 272-3603 Internet Address: belavoce@ix.netcom.com =================================================================== NOTES: The best known clay-based humidifier is the "Guardfather", which when used with a ClimateCase will retain 50% +/-5% in fairly extreme conditions (down to ~20% ambient RH). Guardfather humidifiers only cost about $2.00 from Elderly Instruments in Lansing, MI (517) 372-7890. FAX is (517) 372-5155. They also have about the lowest prices on the ClimateCase thermal/humidity protective covers also. Tyvec or MIL-std packaged desiccant can be obtained from ADCOA (manufacturer), or one of its dealers. ADCOA's phone number is 1-800-228-4124. IMPORTANT!!! MAKE SURE that you use a LAB-QUALITY humidity guage, preferably solid state. Note that most small humidity guages have accuracies of +/-20%, which is dangerously imprecise. Other types may be designed for weather forecasting use, and may be mechanically undesirable since an instrument case can see fairly rough action (shocks) every now and then. This type will not maintain accuracy if it is knocked around. Additionally, most humidity guages supplied with currently available humidifiers are accurate to +/20 to 30% only (and don't ask me why they supply such junk!) I guess, the cliche "ya gets what ya pays fowr" applies here too. Take Care...