Recently purchased a Gretsch steel body resonator guitar with aluminum drum. I'm assuming that the steel has at least 14% chromium to make it stainless. But I'm ignorant about the metal composition of all the bits and bobs that holds everything together. It has a wood neck, fretboard and headstock. Gretsch unfortunately offers no recommendations on humidification. I'm guessing nothing on this guitar is susceptible to corrosion (other than the strings) so I'm ready to humidify the case for the sake of the neck but just wanted to check with you guys first.
I'd think not. The neck is pretty ruggedly built and the body (of course) doesn't need humidification. Adding humidity may do more damage than good.
Stainless steel has both chromium and molybdenum to stem corrosion. Carbon content affects corrosion too. More carbon generally means the steel is harder, but also increases susceptibility to corrosion. I'm not sure of the type of steel in Gretsch's resonator. Apologies for the geek moment.
I really like the Gretch resonators. I want one too, by the way. :)
Seeing as the spammers have serendipitously resurrected this thread, I get a chance to answer your question. In short, I love my resonator. The sounds it makes are incredible. It sounds like the love child of a banjo and a tuba. Twangy yet thick and full. It's unmatched for playing blues and I know that you have an inescapable draw to that genre of music as well. So, I would definitely recommend you getting one eventually, The full steel bodied dobros still sell for less than a grand. The wooden bodied guitars with metal resonator are only a few hundred bucks but they don't sound nearly as good. Right in between the wood and the steel (in terms of price) is the copper bodied resonators which sounds just as good as the steel.
I'm pretty sure that the steel bodied resonators contain enough chromium to make them stainless and therefore rustproof. I'm guessing that the copper bodied resonator is rustproof as well. But none of that rustproofing really matters anyway because you don't need to humidify them.
I don't even bother with humidifying my guitars anymore. More than a year ago I purchased a dozen dependable and accurate solid state bluetooth hygrometers. They're accurate to within about +/- 2 % humidity. I put one in each of my guitar cases (with and without guitars) and monitored them 24/7 for many months using a smartphone app that records every measurement. What I found was that the humidity inside cases that lack any type of humidity control system remained at around 50% +/- 2 %, year round. Even here in Michigan where humidity varies wildly. So the whole topic pertaining to humidification of steel guitars (or any guitar for that matter) is a moot point. It's waste of time and a scam.
The gold standard for humidity control is widely believed to be those D'addario (also some other brands) goo bags that keep case interiors at 49% in any climate. During my little scientific investigation I found that they actually do that very consistently. But then, they're only marginally better than doing nothing at all.
In fact, when I did use any sort of humidification system inside my guitar cases, the humidity inside the guitar bodies of acoustics consistently rose up to between 60 and 70 percent, which I'm pretty sure is high enough to warp wooden instruments.