Wood racks and humidity


I'm thinking about upgrading my rack and like the appearance of the Butcher Block Acoustics and some of the Timbernation products. My system resides in a basement, where humidity in summer sometimes reaches 60 percent. I have a dehumidifier, which I run as needed. The previous owner of my house was a musician in a symphony, and he successfully stored sheet music in the basement here, with the aid of dehumidifiers.
The Butcher Block Acoustics website cautions that their racks should be in environments where humidity remains in the 35 to 45 percent range.
Does anyone here have experience with wood racks and higher than recommended humidities? Am I asking for trouble by buying a wood rack rather than something with metal posts and MDF shelves? I expect to move in the future, and a wood rack would look better with other furniture as part of a setup in a room of the house rather than in a basement. For the foreseeable future, the stereo will remain in the basement. 
conlad
The problem with wood in this situation, all situations really, is called wood movement. Wood slowly absorbs moisture over time and as it does so it expands. One problem is it doesn’t expand equally or uniformly. Woodworkers know all this and here you can actually calculate how much your rack will move (expand) in your basement https://www.woodworkerssource.com/estimate-wood-movement.html

MDF is wood and so no different, except that with MDF it distorts all ugly and loses all strength and never goes back like wood does when moved to low humidity. I would avoid MDF unless dirt cheap and used with the knowledge it may well be a total loss if used there long enough.

If you still want wood I would look for a rack that uses wood legs with steel or other hardware attached, as opposed to a solid wood rack where everything is wood connected to wood. That type of construction the movement can physically tear the joints apart unless they were properly designed for this. Since you already know the manufacturer specifies a lower humidity then guess what, it was not designed for this!

You can still use wood, you just need to be aware and think very carefully. Otherwise you wind up like a friend of mine, spent months building this beautiful cabinet and when he showed me I said why’s this piece sticking out half an inch? "Wasn’t like that when I put it together!!!" He didn’t know about wood movement. Once you do, look around, people that build stuff like cabinets, raised panel doors, there is a lot more skill and knowledge involved than appears at first glance.
If you want the best sounding rack that will not warp look at the Symposium Foundation.It is the best sounding rack at any were near the price.
Thanks for early responses...confirming my suspicions. To clarify about MDF, I was looking at Solidsteel series 3, which has MDF shelves that are painted. Symposium Foundation does appear to be a much better made rack that Solidsteel 3 and is priced more like the Solidsteel lower-end Hyperspike series (which has MDF shelves that are painted or coated). I'm happy to have more responses and am open to hearing about any rack brands that don't cost a fortune.
I have 3 Solid Steel Racks in 2 separate systems.  I love them. 
Look at Adona. They bond MDF to granite with a layer of polymer between. Works very well, but I don't worry about excessive humidity here in Arizona.
I live in the Pacific Northwest and our humidity runs from 60 to 80% outside.  I have a timbernation rack where the wood legs are screwed to the shelves.  No problems whatsoever.
I have a Timbernation rack that is over 2 years old. Live in a very high humidity (swampy) location and humidity inside the house can get fairly high since my wife is cold blooded and keeps the AC very warm. I've never noticed the slightest issue with the rack. Sample size of one doesn't tell you much but better than nothing! 
Sounds like actual experience is you will be fine. Manufacturers often exaggerate to cover themselves against having to replace stuff customers screwed up. If you want a great DIY rack rock solid yet dirt cheap you are welcome to copy mine. https://systems.audiogon.com/systems/8367
I made my own rack using two inch think hard maple with a live edge. I bought an eight foot length and halved it. Sanded it down nice and stained it and lots of coats of poly. For legs I used 3/4" threaded pipe and flanges and I placed a thick rubber washer between the metal flange and the wood surfaces. I bought shorter pipes for the legs from floor to bottom shelf and longer for between shelf to shelf to give some clearance above the gear for heat dissipation. Spray painted the legs gloss black and with the shiny maple it looks great. After looking at the cost of the Butcher Block Accoustics I'm glad I did! What makes them accoustic?!
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I am a carpenter/woodworker w/ 45-50 yrs experience. MC has given good info. However, the shrinkage is calculated for RAW wood. Sealing the wood is necessary. IMO, its NOT an option. It seals the wood against shrinkage. Does that mean there will be NO shrinkage? No. Most woodworkers shoot for 7-8 %. This is the percentage that is usually achieved in a kiln. Air dry is 10-15%, depending on how long it is left to dry. I only use kiln dried which is safer. However I have a friend who has used a lot of air dried with good results.  I won't take the chance on that. But many do. That said, I have an all wooden turntable including the platter. The platter is made with a resin and covered with a veneer (cocobolo). There is no cracks whatsoever in it. There are a few minor surface cracks in the veneer on the plinth. But they are small and have no effect on the sound. I also have built a stand with sand box on top using wood. Again, I'm sure the wood moves some but what is the detrimental effect? I think none

Another problem encountered is the use of thick boards. They retain more moisture than  the thinner stock. And most racks use 2 inches thick or more. IOW, the moisture content which is sealed in can cause a problem & often can cause problems. It can be remedied so as not to crack but that adds cost. Often thicker stock is air dried. And air dried material is less expensive. 

So the question is not whether the wood moves? Most everything does expand & contract with weather change. Steel does , although at a much lower rate. The question to me is this. Does the movement cause troubles. I don't think it does. But in the end, everyone must choose for themselves. Considering the low humidity levels that  Timber Nation specifies makes me believe they probably use air dried material. My own house fluctuates between 30 & 55% humidity. According to their specs, I doubt any house in the nation would be an appropriate candidate for their racks unless they use humidifier in winter and dehumidifier in summer, which is more exception than rule.
@jab 

Before using any wood product, let the wood stand in the intended room for days before using
This is the rule for wooden flooring, paneling, etc, that will be joined together on site. This is to acclimate the wood which has generally been stored in a cold or hot warehouse without climate control. It needs the time to stabilize which it will do in a climate controlled area. This is not the case generally with furniture because all the surface has been sealed which helps stabilize it. You may remind me that this acclimation applies to pre finished hardwood floors. This is true. However, only one side is sealed, not all the exposed surfaces.
I have several Maple racks in my basement in Ohio including Butcher Block Acoustics 3" thick shelves. I do run a dehumidifier in the spring, summer, and fall and have not had any problems at all.
Hi Conlad -

May be too late to the party, but I have several, if not most of the racks/shelves mentioned already here and feel the need to comment:

The Symposium Acoustics Segue shelves and newer Foundations Ultra Top 4 shelf rack I now have (5 months old) are the "best heard" and the best value I have found and own for reasonably priced and "best value" products of their type.  They are not prone to humidity variations.  I have been through a few racks....
I bought (ordered) this rack from DevaAudio (Kansas); best value found.

The (also) new SolidSteel S3-4 rack I have is not even in the same ballpark as the Foundations rack - price-wise or quality-wise.  I also have the older SolidSteel 5.4 welded steel rack and in the past used ~2" thick Michigan Maple butcher block (out of Petosky, MI) shelves cut to fit this rack. While it looked nice I wanted better - the rack would visibly wobble when a nearby door was opened or closed -  so I bought Symposium Segue shelves to fit, but it was still not optimum.  So I went with the Foundations rack.  It is clearly superior to any other rack I have used and mentioned here.

The Foundations rack (designed/made in the USA) uses 1" thick shelves similar to the Segue.  The bottom appears to use a sealed and finished fiber-like material.  The top is aluminum.  The SolidSteel (made in Italy) S3 shelves (28MM thick) are a painted MDF on one side and a rather thin sheet of composite material (laminate) on the other, considered the top.

The Foundation legs are almost 2" dia. and are solid aircraft grade aluminum; they are bombproof once built up.  This rack is extremely solid (no pun, really).  The S2, 3, and 5 racks all use a hollow aluminum that is fairly soft and thin walled that measures 30MM dia.  Even really torquing down on their legs when making the rack will not prevent it from being anywhere as steady as the Foundations rack of the same number of shelves.

Yeah, I know it sounds like I do this sort of thing for fun...
...I should also note that I designed and had built an 2 x 4" oak framed 3 shelve turntable rack with the mentioned Mich. Maple BB as a top.  It is rock solid but likely not the best; yes, wood does "move".  I keep a combo humidity/temp meter in the room to monitor as needed.  Ironically, I need a humidifier sometimes, not a dehumidifier.  And I am from the Midwest so I do know about basements of suburban Detriot homes.

Finally, I have tried many DIY attempts with Ikea wood products and while it was fun and looked very nice it was no were near what I got with the Foundations rack. 
Hope the above helps Conlad.

dadsears


Conlad, I make gallery furniture including $60,000 conference tables and $30,000 entryways.
Sealing wood will not keep it from expending/contracting with humidity. It just slows it down. Air dried is always best but it has to accommodate to the environment for at least three years. Kiln dried is faster but tends to case harden and can do some very strange things when cut due to tensions created in the drying process. Very few of us have the luxury of using air dried wood.
Real butcher block has an end grain face and is very unstable with humidity changes. As long as it is not trapped it is fine, for cutting board use. No self respecting wood worker in his right mind would use it in cabinetry. What most people call butcher block is butte joined long grain narrow boards which may or may not be stable depending on how the wood is cut, joined and what species is being used. A panel made this way using quarter sawn mahogany will be very stable and would make a great rack if you could afford it. Any quarter sawn wood with the grain oriented up and down in the panel will do very well as the panel will change in thickness with humidity instead of width as you would see with flat sawn wood. However no good woodworker would trap a solid wood panel in a frame. They would float it to give it room to expand and contract. 
In an environment that has deep humidity changes it is best to use a plywood construction with solid wood edging. I have made panels 2 inches thick with a 1/4 inch thick surface veneer that are still doing well after 28 New England Winters (my front doors).
If you like the look, Mahogany and Teak are the best woods to use in this application as they are the most stable. Maple is the most unstable. Oak and Walnut are in the middle, white oak being the best. It is important that the grain be oriented in the same direction throughout or the board will fall apart in time. Just look at the end grain. It should all be pointed in roughly the same direction. Oil is the best finish in this application. Surface finishes like lacquer and polyurethane will crack eventually. IMHO polyurethane is the worst finish ever concocted by man. It looks awful and is a PITA to refinish.  
If you have your eye on something send me a photo and I will tell you what I think. 

Mike
Not to hijack the thread but mijostyn, what would your opinion be on using clear redwood for a stereo rack? I have 4 -  2" x 12" x 7' of clear redwood I bought in 1976 that I was thinking of using. How would you cut it and glue it? Lo-boy with 2 full length ( approx. 5' long ) with 2 half shelves. Threaded pipe frame.

Boss302