de-Humidipaks?

[Guitar Cowboy]

 The people who make Humidipaks claim that it is a "two-way" humidity control system. However, this spring I am having trouble keeping my guitar cases  below about 60% humidity. My three sets of Humidipaks all seem to be at about maximum absorption capacity - i.e they feel about the same as they do when you take them straight out of the pack. So I don't think that  this "two way" humidity control is "automatic". They are not taking excess moisture out of the guitar cases.

So it seems like the trick is that you need to get ready for the de-humidifying season by hanging on to your dried-out Humidipaks  so that this time of year you can use them "in reverse" to suck excess moister out of the case.   

 I have had success recharging them in the winter by putting them in a sealed Tupperware container above water.  Does anyone have a successful way to dry them out so that they can de-humidify this time of year?. Right now I have them in a Tupperware container sitting above some Damp-Rid, but no change in consistency so far. Any other ways to effectively de-humidify your guitar cases or is a room dehumidifier the only answer?  ( I've tried the hair dryer method mentioned on the Taylor spec sheet) Can room humidifiers effectively dehumidify down to the 45%-50% range. It seems like there designed to handle much higher humidity levels.

[timfitz63]

I noticed the same kind of thing with the Humidi-Paks in my guitars during a recent trip back into Texas:  they'd been in the cases for [literally] months and didn't seem as if they'd dried out at all.

Consulting my hygrometer, I noted that the air inside my house was being measured at ~70% RH.  With all the rain Texas has gotten lately, I'm not a bit surprised.  To make the matter worse (from a moisture standpoint), the A/C clearly hasn't been running much during this period; the outside temperatures have hardly gotten above 80 degrees F -- event during the day -- due to the frequent overcast conditions.  When I bumped the A/C on, the humidity level inside the house began to decline, and for the short period I was in town (~1-2 days) it got down around 60% RH.  If I'd have stayed longer, it probably would have gotten much closer to ideal (~50% RH).

Any decent central A/C system will be very good at removing moisture from the air; that's going to be the best place for you to start -- get the overall moisture content of the air inside the house as low as possible.  Having never used them or researched it, I'm not sure how much moisture a room-size dehumidifier can remove; I suspect they're designed to augment the moisture removal provided by a central A/C system, though.

Regarding the Humidi-Paks themselves:  I think your approach is valid; using dried-out packs should be effective in absorbing excess moisture.  As for the best method of drying them out during this season of the year:  that's going to be a tougher one...  Unless you live in the desert Southwest, just leaving the silly things on the kitchen counter with summertime humidity levels inside the house will cause them to saturate with moisture.  Unless you can place the packs into a low-humidity environment without cooking them, I don't see a good way to do it.

Now, all of that being said:  I don't believe a few months of higher (i.e., 10-20% above ideal) humidity levels will cause permanent harm to these guitars.  It's when they're left unchecked in these kinds of conditions (e.g., in the tropics, where the humidity level never drops below 70%) for much longer periods that problems would develop.  Same is true for extended exposure to very low humidity levels (e.g., in desert areas, where the humidity level is never above 20%).  I suspect that seasonal humidity shifts in temperate climates are probably taken in stride, and the overall effects tend to average out.

But like you, I still try to hedge my bets as much as possible by maintaining the humidity levels as close to ideal as I can...  Wish I had a better answer for you though...

[Earl]

There are always the silcia gel packs that are tucked into the packaging of many products these days.  You can get larger amounts from a scientific supply house.  Once saturated they can be recharged by baking at moderate temperature (say 150°) for a few hours.  The Humidipaks can probably survive the same drying treatment, but I don't know for sure.  They can only work "two-way" when the RH in the vicinity is either higher or lower than their 48% standard.

I've never had to worry about de-humidifying.  I hear your words, but don't comprehend what you are saying......     

[timfitz63]

There are always the silcia gel packs that are tucked into the packaging of many products these days.  You can get larger amounts from a scientific supply house.  Once saturated they can be recharged by baking at moderate temperature (say 150°) for a few hours.  The Humidipaks can probably survive the same drying treatment, but I don't know for sure.  They can only work "two-way" when the RH in the vicinity is either higher or lower than their 48% standard.

I've never had to worry about de-humidifying.  I hear your words, but don't comprehend what you are saying......     

Yeah, I thought about silica/desiccate packs as well.  I use some for 35mm camera equipment that I have to keep mold/mildew from forming inside the lenses.  And it's true you can 'recharge' those by baking them.

But I'd be leery of baking these Humidi-Paks, even at relatively low heat temperatures like 150 degrees F.  I'm not sure how the gel or the permeable membrane would react; the heat may case the gel to expand to the point where the pack ruptures, and/or the membrane might become brittle enough to eventually crack...

[Earl]

Agreed.  I don't have any direct experience with Humidipaks.  I won a set of the original ones at a Taylor Road Show years ago, but right about then reports of leaks started appearing.  I did buy a used ukulele once where one had leaked inside the hard case - what a mess!  So I've never taken them off the shelf, and don't know much about recharging them either way.  My "sponge in a soap dish" method has worked well for humidifying for a long time, so no need to mess with success.  And I have recently supplemented the sponges with "water beads".  They stay damp a lot longer than plain sponges.  Maybe dried out water beads could work to re-absorb moisture inside a damp case....

[Jersey tuning]

DUH, how does one know (without a humidistat) when the moisture absorption potential of a humidipak has max'ed out?

As far as recharging the dried out ones, I just leave them out when the humidity in my living room exceeds 50%. And damp sponge in the dead of winter, when the humidity goes as low as 26% (33% when I run our portable humidifier).

[Earl]

Not to be too picky, but a humidistat controls humidity.  A hygrometer measures it.  Similarly, thermostats control temperature, while thermometers measure it.  But don't feel bad.  Several of my engineer friends cannot get this right, and really should know better.

[timfitz63]

DUH, how does one know (without a humidistat) when the moisture absorption potential of a humidipak has max'ed out...?

There isn't really any way to definitively know when Humidi-Paks have become saturated -- which may be your point.  But it's a sure bet that they will saturate when the humidity level is consistently above 50%.  How quickly they reach saturation is related to how much above 50% RH the environment is and for how long the packs are exposed to that environment...

[Jersey tuning]

Not to be too picky, but a humidistat controls humidity.  A hygrometer measures it.  Similarly, thermostats control temperature, while thermometers measure it.  But don't feel bad.  Several of my engineer friends cannot get this right, and really should know better.

Blame it on my wife. She's been calling our hygrometer a humidistat all week.

[Guitar Cowboy]

DUH, how does one know (without a humidistat) when the moisture absorption potential of a humidipak has max'ed out...?

There isn't really any way to definitively know when Humidi-Paks have become saturated -- which may be your point.  But it's a sure bet that they will saturate when the humidity level is consistently above 50%.  How quickly they reach saturation is related to how much above 50% RH the environment is and for how long the packs are exposed to that environment...

I think in order for the humidipaks to de-humidify, they need to feel a bit crunchy- the way they get in the winter when they have been supplying humidity and then need to be recharged. I gave up on trying to dry out my humidipaks ( in Tupperware above damp rid ... the reverse of placing in Tupperware above water). I bought some silica gel packs and placed a couple in my case and they helped to bring the humidity down to 45-50%

So I think  that saying that they provide two way humidity control is a bit misleading . If they are fully saturated (like they should be when you take them out of the pack), its not like you can throw them in the case and expect them to keep the humidity level at 48%. They wont do anything if they are at or above ambient RH

[MrHarryReems]

What about maybe putting them in tupperware with a bunch of dry silica gel packs?  Move the moisture to the silica gel packs that you can bake...