Aluminum foil humidifier

[moestock]

Sorry if this is a dumb question, but is there any reason I should'nt make a humidifier out of aluminum foil?  I've seen people make them out of plastic cups, so basically I just need something to hold a sponge in the sound hole right?  I know they are not expensive to buy but if I can spend nearly $0 instead of $5, why not?  Would it cause any sort of corrosion to the electronics or strings with the metal in there?  Thanks for any help.

[rainrainwash3]

Just use a plastic sandwich bag and poke holes in it with the moist sponge inside.

[moestock]

hmm, hadn't thought of that. Could just clip it to a string with a clothes pin or something. Thanks.

[liko]

From a corrosion standpoint, aluminum and brass do have a significant difference in anodic index, which in plain English means that corrosion is possible. It's not as high as the one between copper and zinc, which are the two metals usually used to make lemon batteries, but it will have an effect. Luckily it will be the aluminum that corrodes in this case and not the brass/bronze strings or copper wire, because the aluminum is more likely to donate electrons (to become a positively-charged "anode") and thus to oxidize.

I'd stick with plastic. The sponge in a holey Ziploc baggie trick is as old as Ziploc baggies themselves; as long as the sponge isn't dripping wet (lightly wring it out so its damp to the touch) you can put it pretty much anywhere. Just make sure you also have a hygrometer (humidity sensor) in your case, and check it regularly. Overhumidifying a guitar can be as damaging to its sound and playability, and even its structure, as underhumidifyiing it.