Advice for Travelling with Stringed Instruments
Air temperature is not your real enemy - humidity is.
Straight forward physics tells us that warm air carries more moisture (therefore higher humidity) than cold air, but the world’s weather systems are much more complex than that. Two of the driest places on earth are, the Sahara Desert and the middle of the Antarctic - opposite ends of the temperature spectrum but, for different reasons, incredibly instrument crackingly dry.
The middle of large land masses tend to be dryer than coastal regions.
If you are traveling across continents, check the relative humidity.
If your instrument has been stable for a while in a relatively dry climate (i.e. less than 45% relative humidity) and you travel to an area of high humidity, the instrument will swell a little but should hold together. If your instrument has been stable for a while in a higher humidity climate (i.e. above 50% relative humidity) and you travel to a dryer area, it will release moisture, it will shrink and you do stand a chance of it cracking. How can you stop your valuable instrument giving out it’s very valuable moisture content? There are a number of proprietary humidifiers available which either sit inside the instrument or inside the case. These are simply small sponges in a variety of forms held in different types of casings, designed to release moisture in a controlled fashion, thereby keeping the relative humidity higher in the immediate environment around your instrument.
Hiscox cases are excellent value for money and for a lightweight case give superb protection...
...however we do not guarantee that they are airtight. There is not a lightweight, carryable case on the market that guarantees to be airtight, it can be done but the cost is very high. The armed forces of the world do use high spec airtight cases to protect electronic equipment in battlefield situations. The cost? in the region of £1000 for a rectangular box!