Case Color & Temperature

[Tim2723]

You know Almeria, you didn't really have to go to all that bother (these are well known physics principles), but thanks for the very stark demonstration of an important concept for musicians to understand.

The reason cases are mostly black is because musicians are supposed to be out at night, like vampires. Mic stands, speaker stands, and cables are black so that they're conveniently invisible on a dark stage. Everyone knows that.

[almeriastrings]

I think we need to change that to "everyone should know these well-known principles"!

If they did know it, I would not have 2 guitars and a mandolin on my workbench right now, all with internal separations, and one with a total neck joint failure. All of these happened over the last week. Comment from one owner "I thought it would be OK in the case"! The one with the neck joint failure is a mandolin and it was in a "look-alike" Travelite type case.

Hey, I know it - that's why I prefer white cases

[journeybear]

Also, theoretical principles need to be put to the test. Experiments like this are useful in that they explore the practical application of theories, and unforeseen factors beyond the basic premise may interact, causing results different from what may have been assumed. Granted, some research projects produce obvious results, but this is also useful, confirming what had previously been only suspected to be true.

I'll reiterate my curiosity about silver-colored cases - the rectangular ones with metal-reinforced edges (aluminum or steel, not sure which). I wonder whether the metal content conducts heat due to its ductile nature, or reflects heat due to its shiny nature. These may be harder to obtain for the experiment, due to rarity and cost. Similarly, it is worth noting that silver colored cars are very popular currently, and I believe this is because they offer both stylishness and heat resistance - cool in both ways.

[foldedpath]

I'll reiterate my curiosity about silver-colored cases - the rectangular ones with metal-reinforced edges (aluminum or steel, not sure which). I wonder whether the metal content conducts heat due to its ductile nature, or reflects heat due to its shiny nature. These may be harder to obtain for the experiment, due to rarity and cost. Similarly, it is worth noting that silver colored cars are very popular currently, and I believe this is because they offer both stylishness and heat resistance - cool in both ways.

(Raises hand!) I can answer that, if you're actually talking about metal cases.

A long time ago, I used to own a bunch of Halliburton aluminum cases for my day job (advertising photography). I eventually replaced them due to the "steal me!" factor when checking them as airline baggage, but I used 'em for years, including many trips to Central and South America where direct sun can be brutal, and I was based in Miami where the conditions are almost the same.

It's true that the polished aluminum surface is good at reflecting heat. The outer surface of the cases would get warm to the touch in direct sunlight, but never as hot as a black-colored case would. However, that reflective quality is offset by aluminum's very efficient heat conduction to the inside of the case. I didn't worry about it too much with the photo gear I was using at the time, because the foam-filled interior provided additional insulation. And generally speaking, photo gear (except for the actual film) is less fragile than a wooden musical instrument, when it comes to temperatures. I used to set all my lenses out in direct sunlight to dry, as a fungus prevention method when I was working in places like the Amazon.

Anyway, I never ran the kind of tests Almeriastrings is doing, but I suspect that the advantage of high reflectivity in sunlight is at least partially offset by that fast heat conduction. With enough foam behind it, that wouldn't be a major problem, but now you're talking about a larger and heavier case. I think fiberglass or CF probably wins if you're looking for the smallest volume and weight in a case, with a reasonably reflective exterior color.

[journeybear]

Thanks for that. Sounds like it's sort of a wash, with those two factors cancelling each other out. If such a case is still cooler than a black case, that would be some kind of victory. Wonder how a black case with metal edges compares to a plain black case? While searching the interweb I found black-and-metal road cases to be vastly more common than silver-and-metal. Again, I believe this is a stylistic concern - they sure do look cool. In the other sense. Hopefully, as you mentioned, there is sufficient heat insulation provided by the foam padding.

[Darryl Wolfe]

Thanks for your effort. That puts thing in real perspective.

It would be interesting to see the effect of a silver Small Dog case cover on any of the non-white cases. (or the white one for that matter)

I have a hard time carrying anything but black for tradition. I recently purchased a black Pegasus, but it does have the cover.

[coletrickle]

What about the use of reflecting mirror like covers for cases? I've seen these on guitar cases for gigging musicians (Andy Falco for example). I wonder if using something like that really makes a difference. I guess the principle has been tested in cars for a long time with the windshield screen.

[almeriastrings]

In terms of reflecting radiant heat, white or highly reflective silver is invariably going to come out best, black worst. Other colors will vary, but often, the difference between those colors (green, grey, blue, yellow, etc.) and black is not that significant. Objects appear white if they reflect all colors, black if they absorb all colors. There are obviously gradients between these extremes. A light colored case cover would certainly help over a black case (and these normally also feature additional padding as an extra benefit). I have a silver colored Eastman fiberglass case here, I'll test that. Also the Hiscox ivory. These are obviously not identical in terms of other design features, as the Eastman has relatively little padding, where the Hiscox has quite a lot, but it will be interesting to see the results regardless.

I think we can say with some confidence, however, that if you live in a very sunny, hot environment a white case really does have significant advantages, and that a black case in full sun can very rapidly attain internal temperatures that will damage your instrument. Padding only buys you a bit of extra time. Leave it long enough and a case absorbing high levels of solar energy will effectively bake your instrument eventually. The more heat you can reflect away in the first place, the better.

[journeybear]

Maybe using all that solar energy to one's advantage would be in order. Some sort of solar-powered air circulation system could be installed. I doubt an effective air conditioning unit small enough to fit into a case would be feasible, but there are lots of efficient small fans available, and some sort of venting tubes could be incorporated into the body of the case. Though I wonder what really is to be gained by pumping warm (or hot) outside air through the inside of a case ... Hmmm ... never mind.

[Larry S Sherman]

What about the use of reflecting mirror like covers for cases?

You need 5,800 tiny mirrors to make your case into a death ray



Larry

[Brutus1999]

I wonder if a very lightweight, perhaps ripstop nylon or a very light vinyl, in silver or white color could be tailored to slip over a black case, kind of like a pillow case? . I know, this is more complex, crazy doo-dad stuff, but for someone who is in Arizona or Spain type intense sun, maybe it would be a relatively cheap solution for occasional use? Okay, now one of YOU try this out ...

[raulb]

Recently, I was concerned about my black mando case in my truck in the sun, on a hot day. I put a cooler pack in the case, wrapped so it would not perspire on the mando or case interior. Of course the pack melted, but the mando never got hot.

[almeriastrings]

Silver vs Black thermoplastic (guitar cases here, as I had no comparable mandolin examples)



After 25 minutes





After 1 hour

[almeriastrings]

Internal temperatures

Black case



Silver case



Quite a difference. The black case reached an external temperature of 71.8 degrees C (161.24 F) while the silver case peaked at 52.2 C (125.96). Internally, the black case reached 53.5 C (128.30 F) while the silver case peaked at 46.2 C (115.16 F). Both are hot enough to seriously damage an instrument, of course!

Here's a very interesting image taken with an infra-red thermography camera towards the end of the test period:

[yankees1]

Very interesting and results are what I would expect anyway! A lot of school bus roofs are painted white to reflect the sun for this same reason but-------------- I still would not want a white mandolin case !

[Andy Alexander]

Here is a tip for when traveling by car with your mandolin. Buy a X-large high quality chest cooler (they are rated for how many days they will keep things frozen). There is room for at least two mandolins or a mandolin and fiddle in them (use a tape measure when buying). This will help to protect your instruments from both heat as well as cold. It also keeps them out of sight in your parked vehicle. Now you can feel a little more comfortable rolling up the windows and locking the car when running into the store or when going to the stage at the festival. Although the cooler greatly slows down the temperature change, the inside of the cooler will eventually reach the temperature of the inside of your car.

[journeybear]

Interesting idea, regarding both temperature control and security. I suppose you could extend the effectiveness of the insulation by putting some freezer packs in with the instruments - carefully wrapped to avoid causing condensation, of course.

[Andy Alexander]

I have never felt the need to go to that extreme but it would definately prolong a safe temperature. I suppose a hot water bottle or two would help during the winter in colder climates. Not only does maintaining your instruments in a "climate controlled" environment protect them from damage, it also greatly reduces tuning issues.

[AlanN]

When I went to festivals and tent camped with my car, I would cut out cardboard inserts for all 6 windshields (4 doors, front, back) and tape them to the insides. You would be amazed how much heat that cut down inside the veehickle. The instruments were secure and climate controlled.

[Tim2723]

Correct me if I'm wrong, but I believe the 'heat' component of white light lies in the infrared wavelengths. I wonder if a case could be devised to reflect just that?