Boveda, Stretto, room humidifier

November 4, 2019, 5:41 AM · As we slide into winter, the humidity is starting to slip down a bit. It isn't a problem yet, but it will be. I've both a room and case hygrometer - I check both every few months with the salt test. So I've a few questions.

1. I've a room humidifier, it just has low/medium/high settings. I made it work last year for the room. Even the low setting last winter sometimes caused a fair amount of condensation on the window panes. The windows in my apartment do leak cold air, so am unsure that the condensation means anything. Is this common?

2. I bought a 49% Boveda (for instruments) this summer. It came with a sleeve, which is nice. My only question is that it's a bit too large for the space under my violin's neck without actually touching my violin. That makes me unconformable but is this actually a problem?

3. Is the Stretto better than Boveda? It looks like it is smaller than the Boveda which might be better. My case hygrometer is a Stretto, though that doesn't really matter

Replies (22)

November 4, 2019, 5:54 AM · The advantage of the Boveda is that it doesn’t really get wet. I find that, depending on the case I am using, I can tuck one or two in the space next to the pegs. The sleeve holding two pads helps in that a lot, and keeps the gel at a slight distance.
Edited: November 4, 2019, 7:50 AM · I haven't thought about windowpane condensation in quantitative terms for a very long time, so I'll give it a try. Let's say your window panes are at 32 F (0 C) and your room is at 68 F (20 C). The vapor pressure of water (the partial pressure required for saturation) at 20 C is 17.5 torr. So 50% RH would be a partial pressure of 8.75 torr. At 0 C, the vapor pressure of water (again, that's the thermodynamic maximum partial pressure of water vapor) is 4.6 torr. So when your 68 F room air at 50% RH, carrying 8.8 torr of water vapor encounters a surface at 0 C, where a vapor pressure of only 4.6 torr is required for saturation, the moisture condenses on the cold surface because air at 0 C cannot hold 8.8 torr of water vapor. I conclude that condensation on your window panes is something you should probably expect to see, but it kind of depends how well insulated your windows are. One of those infrared thermometers or contact thermometer strips might help determine that. If you get an "energy inspection" of your home, the technician will have the tools necessary to determine this... frankly I recommend it. Usually people see condensation around the edges of their windows where there are parts made of metal or vinyl which provides a means of thermal conduction. If you're seeing condensation in the middle of your window panes, or if the condensation is actually freezing (frost or frozen droplets) then you need replacement windows -- and fast! Get the energy inspection -- you will learn a lot about your home.

Edited: November 4, 2019, 8:52 AM · I hear you Paul - I doubt that they are insulated at all - but I live in an apartment and short of moving to another place that may (or may not) be any better, there are no options (move MAY happen next fall...). Still, it's actually good to hear that it's to be expected and I greatly appreciate your comments - very educational!

I am curious to hear any thoughts from this forum on Boveda vs Stretto vs moist sponge in a ziplock bag with a few holes poked into the plastic :-)

November 4, 2019, 10:36 AM · With any DIY product, the one thing you want to be absolutely sure is that there cannot be liquid water leaking from it, no matter what angle your case gets stored or no matter how much stuff gets jostled around inside. The products that are based on silica gel are probably the best bet in my opinion. The kinetics of release and absorption is more gradual which is fine for situations where your case gets opened for maybe 5 minutes at a time.
November 4, 2019, 11:18 AM · Unlike most case humidifiers (which can only add moisture), the Boveda will either release or absorb moisture in an attempt to keep the moisture relatively constant, for some undermined amount of time, and depending on the situation.

Should the Boveda leak, it will release compounds much less benign than water.

Edited: November 4, 2019, 12:02 PM · A technique I have used for several years is to find a small plastic "clamshell" box, drill a pattern of holes in it, and press one side of the box firmly into a block of florist's foam (our nearby florist has scraps that have cost me nothing). Using a sharp kitchen knife, cut off the excess foam flush with the top of the box using the dimensions of the box as a guide. Then make some mold-free wetting solution by taking appx 250ml of distilled water, put (only!) one or two drops of chlorine bleach in it, and use this to saturate the block as needed. Mine last an incredibly long time between re-wettings, keeps the case at very constant humidity, and never leaks in the case. If there's interest in this I can post a photo of several iterations of this I have made.
November 4, 2019, 1:06 PM · Thanks for the information David, I hadn't thought about that might happen should the Boveda actually leak, I was mainly concerned because it would actually touch my violin in my case.

Charles, I'm intrigued, I think I've the idea, but pictures would be helpful.

November 4, 2019, 8:01 PM · I took some photos of the process, and of two versions I made - at this Dropbox link:

1) Find a suitable box or other container (Any good plastic box you can drill will do, but I particularly like the stainless steel one - It's a repurposed surgical instrument box from an eye surgery tray)

2) Perforate the lid with a drill bit, or other means.

3) Push one side of the open box firmly into a bigger block of florist foam - it is very soft, and will "self fit" into the box.

4) Trim off the excess with a very sharp, large kitchen knife, using the edges of the box as a guide. Hold the foam in - it tends to lift.

5) Make a supply of distilled water with a few drops of chlorine bleach to prevent mold. Don't over-do the bleach.

6) Wet the foam periodically by soaking the foam until "refusal", tip to drain to avoid leakage, and put it in the case.

Mine lasts for days - it's incredible how much water the foam will safely hold. The foam needs to be replaced every now and then, but it's quick. You might need to devise a method to secure yours in the case. My shoulder rest holder holds the big one down, and the small one is fine free in the accessories compartment.

Hope this helps! If you make one, please send a photo.


Edited: November 4, 2019, 9:12 PM · Charles's idea with florists' foam is a good idea. Instead of the bleach Charles is using (which is a small amount, I'll attest), you could use the commercial biocide that is added to the water tanks in piano humidifiers (Dampp Chaser Pad Treatment). It's probably a quaternary ammonium compound but I'm not sure. I don't have the bottle handy and I couldn't find an SDS for it. A little copper sulfate might work too. I'm just not wild about having ANY chlorine inside my violin case.

The Boveda system contains chemicals that are fairly innocuous, but as David says, less benign than water. Typically a Boveda pack contains water that is absorbed into various inorganic salts which range from calcium chloride, magnesium chloride, sodium chloride, potassium chloride, potassium citrate, and so on -- each of which has a certain tendency to desorb and absorb water. In addition the products contain some kind of thickener (I guess that is so that if liquid water is present, it doesn't get runny) and a preservative (citrate or sorbate typically). You can learn all this by reading their safety data sheets (SDSs).

November 5, 2019, 5:39 AM · I really appreciate the ideas and comments. I like the idea of a custom approach that will fit both fit my space needs (which the Boveda does not), and affordable to maintain.
Edited: November 5, 2019, 7:39 AM · Charles, I finally had a chance to check out your photos, and I must say that you've a LOT more room in your case by the violin neck than I do. I really like my suspension case but there is only just enough open space for my violin. I do have three accessory compartments, one doesn't hold more than my Kun, another is much smaller, but there is a good amount of space in the other. The very small compartment MIGHT be large enough for this purpose. Maybe, it's quite small, it won't even hold my rosin when it's in the box, so I just keep clippers and orchestral mute there.

Whether I go with a plastic or steel container, I think this is a good and sustainable solution for me. I will need to find a box I like, and then find a friend with a drill, but I am going to go this route.

I've THIS case, the only difference is it's dark blue, and my hygrometer that came with it is a Stretto.

November 5, 2019, 9:50 AM · Is a case humidifier necessary if a room humidifier is being used for a consistent 45% humidity level, and the case is left open a crack? I assume a case humidifier would be necessary only if the instrument leaves a humidified room for a day or this correct?
November 5, 2019, 10:15 AM · Probably, yes.
Edited: November 6, 2019, 3:52 AM · Erin, I believe that to be correct. But I would rather leave the case closed and latched, because so many accidents happen when a case is not latched. The environment inside the case will stay very close to that of the room anyway, unless a specific effort is made to have the environment in the case different from that of the room.
November 5, 2019, 12:40 PM · I agree with David about keeping your case closed.

And off the basement floor.

November 5, 2019, 1:00 PM · Personally I like both as my apartment is...variable. It will certainly stay in a closed and latched case. Last year I trusted my room humidifier and wasn't so careful with it as long as it was in the humidified room at home, and it needed quite a bit of Luthier attention come spring for the fingerboard. Hopefully it will be better this time around.
November 5, 2019, 2:13 PM · More is better, generally. I most often use Musafia cases with the drownproof seal and the vents in back that allegedly keep condensation from being a problem. Inside that, I tuck a Boveda pack or two. If the room is correct humidity, all the better. But I choose not to plan on that.

November 5, 2019, 10:00 PM · Catherine - I looked up the case you are using, and it does seem like space is tight. Thinking about this - is there room for a plastic pill bottle, like the ones Rx meds come in? If so, it could be drilled in the bottom, and possibly sides too, and fit with foam the same way - jamming it into the block. Water could be added and the bottle closed with the snap or screw lid the bottle came with. If that’s too big, I suppose even a string tube or similar could be adapted to make a really skinny one.
November 6, 2019, 4:29 AM · The Oasis holds a fair bit of water and takes up little room. No real danger of leakage, in my limited experience.

Edited: November 8, 2019, 7:12 AM · I've purchased David's less expensive controller for my humidifier so it won't need to run 24/7, consistency is a good thing.

I like the pill bottle option that Charles suggested. I should be able to attach it with velcro on the inside of my case. Personally I like that space is so tight so nothing can move around - and the 3 compartments plus zipped cover storage (which even includes a netted sleeve).

November 8, 2019, 11:30 AM · I have Oasis humidifiers in all my cases, but I don't really know how well they work.
November 8, 2019, 2:57 PM · Do they lose moisture? Then it's going somewhere.

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