Pulling one out of mothballs... Only so Bryan doesn't say "Rich is just a big talker... "
I built the doors with pine boards and hardboard, screwed one to the wall with some small hinges. This is about a year ago. Shane took a look and said, no way man, those little hinges will not hold up 6 doors. So eventually I redesigned the whole thing with a real budget so I could buy some good folding wall hardware and do it right. This is what I am using.
http://www.johnsonhardware.com/100rd.htm Very nice quality, and a decent price. I got the track in two pieces to avoid shipping by freight. I just shimmed the ends to meet perfectly. The total span is 126 inches. The doors are 22 inches wide, so the hanger is at the center point to balance the doors so they will open very easily. You see the gap at the end of the track, the glider bearings only need to get to 11" from the pillar. The gap I will fill with a block of wood. The ceiling is not flat in those last 4 inches, so the track had to stop short. No biggie.
It took a while to design this one, because of the complexity, and the tolerances. Big doors 2' x 6' that have to glide 1/8" away from a wall for 10' distance, then seal shut with very little leakage. After a couple weeks the CAD was finally done, I started cutting parts yesterday. YAY!
Of course, the joist I need to hang the system from was 3.5" away from where I needed it. So I made a header board out of my secret stash of rock hard baltic birch plywood to transfer the load of the wall to the joist. I have 2.5" screws every 8" and 3" of cantilever on the other side of the screw line to prevent bending of the screws, so I hope it's strong enough. The doors aren't so heavy, it should be fine. (Famous last words....)
Here is a picture of the track bolted to the headerboard.
Tonight my wife and son helped me on the table saw to dice up a full sheet of plywood into 2" strips to make all the door frames. My wife was holding the outfeed, and clouds of sawdust were billowing all over her. What a trooper. My son ran around turning the saw on and off and helping to line up the cuts. My younger son wanted to help earlier in the afternoon but the plywood was too heavy for him to handle by himself.
It is midrange noise that I want to attenuate from the kitchen, hums and motor noise from appliances. But most important is to get rid of the midrange echo from the music system bouncing back from the hard surface kitchen. They will be stuffed with 2" OC703 FG. The side facing the music room will be hardboard with a section of goodpanel at the bottom. I don't want any absorbtion that I don't need. I like a live room as long as it's not out of control. I still need to hang curtains for lonewolf, so that will add some tame. The side facing the kitchen will be thin plywood all the way. Both sides will be painted, but not in time for the G2G.