I am VERY VERY impressed! I have not heard of the open-t pvc joints. are they a specialty item? This bin is going to be HEAVY! Your frame seems to lack "shear-strength". I would secure it to the wall along the top frame so it does not begin to lean.
Hail to the wormy queen! Good luck, Pete

Very cool, but I would highly recommend some bracing on that frame. As Mendopete mentions, shear bracing. All the weight is going to put pressure on those corners to the left or to the right (shear, the thing will twist when moving down) and with those long runs that's a lot of force (think leverage)

I would recommend diagonal cross pieces, but I doubt they exist in those pipes. As you see in all building, bridges etc, all large 'square' sections have a diagonal piece through them so it doesn't collapse. Either going from one corner to the other (the strongest) or at least a piece to support a corner. It's why in iron frames etc, everything is triangles and not squares.

http://en.wikipedia.org/wiki/File:Eiffel_Tower_(72_names).jpg

If you can't go diagonal, might get away with many more vertical pieces for load, and then have more horizontal pieces for support in the middle instead of those long vertical runs. Your system when full is going to weigh hundreds of pounds. If you can't imagine 4-5 people standing on it, needs more strength.

You could also go another way to remove the issue. If you had say a stacks of bricks supporting the top, those won't have such high shear problems are they are not flexable. It's why you see so many bridges have concrete supports (vertical) and the iron lattice for the road (horizontal). Or maybe some wood bracing, stronger and more freedom to make proper bracing. It's just those pipes are so thin and they have some flex they are so prone to shear.

Welcome to the world of large scale construction ;).
Luck.

Edit- fyi, if you are familiar with the worm inn, the maker had made one four times the volume. But he hasn't sold them because the piping system he sells with the worm inn won't support it. He hasn't yet figured a way to support it, not one that ships easily I guess.

Oops sorry, course you know the Inn as it's based on tha, duh, what I get for quick typing. Anyway I had some time to find the link I remembered.

http://www.redwormcomposting.com/fun-stuff/name-that-worm-inn-winners/#comments
"Sharon�cThe Worm Inn MEGA itself is complete. Because of it�fs weight, I�fve needed to source special parts for the stand kit to eliminate sway. I'm working on stabilizing the stand now, and hope to have it ready to go within the week."

I thought you could copy his solution, but after a quick look I didn't see any Worm Inn MEGA for sale. Yours would be a bit more stable as it's wider instead of so long and high, but that twisting torque is still going to be nasty.

Luck, Peter.

This is huge and impressive. I've been thinking of similar ideas for expanding my system in the future.

I will second PeterK2 about the weight and weakness of the PVC structure. I used to use 3/4" PVC and heavy canvas to make iguana cages in a very similar manner to your construction. The typical size for a cage was 3'x6'x6' or 4'x8'x6'.

3/4" PVC at 24 inches in length will bow in a frame like this with weights much over 30 pounds even when the fabric is evenly across it as you did. You can help this by sliding a pipe in the center of the PVC. Maybe see if 1/2" steel conduit or concrete rebar will slide within the 3/4" PVC pipe.

The main weak point I see is where the two T fittings mate together with a small length of pipe. You may want to look at some 4 way fittings as they sell here:
http://www.littlegreenhouse.com/accessory/pvc.shtml

The other potential problem point I see would be twisting and falling diagonally as Peter brought up.

It is hard to see but is the ceiling where this will be kept open to the floor joists above? The simplest fix will be to both support it from above and below. Add some strong anchors into the joists and suspend it with the frame under it still. You'll want to run the bin perpendicular to the joists and tie off to several joists to distribute the weight. While you have the sewing machine out nylon straps with a loop on one end and a ladder lock strap would be easy to make.
http://www.ahh.biz/hardware/ladder_cinch_locks/locks_ladder_heavy_black_plastic.html

I hung my worm inn with a frame of PVC around it to hold square and parachute cord tied off to the frame and some solid anchors in the floor joists overhead.

[I just know I need to be clear as this is a wide open forum, I'm not trying to target you Worms4Tracy - solid anchors in joists are NOT plumbing pipes or electrical conduit these are 1/4" minimum bolts or lag screws with either a hook or eye. Each one should be able to hold an average mans weight minimum]

"buy a bulk order of worms" You should be fine with just the worms you have having the luxuary of growing into their great new home.

"If you can't imagine 4-5 people standing on it, needs more strength." This is a very nice way of saying we have seen systems where the structual integrity of the bin has been cut away and we want to see yours strong because we were all sad when the others had catastrophic yet easily predicatable events occur.

"It's just those pipes are so thin and they have some flex they are so prone to shear." Even some support from on high would help. Is there sturdy roof beams to support the bin with?

What bothered me massively about other systems is expecting to capture vermicompost in a bin below when the bin below does not extend past the areas of vermicompost fall out. One can not simply put a bin below a rack. Vermicompost falls to the outside edges not just as imaginations would have it neatly in the middle.

The other systems I was refering to were the ones made out of multi gallon trash cans.

One of the main advantages of a bag system such as yours is being able to coral and collect the vermicompost without having to dig it out or it falling on the floor and having to sweep around support structures to get it.

For me that is a big plus.

Tracy, like your other supporters here, the first thing which came to mind was the ability of the PVC to hold the weight. I have a four foot long 3/4-inch PVC plant stand which does some sagging under much less weight. I use PVC for other projects as well, and where sagging is an issue you can insert 3/4-inch PVC inside 1-inch PVC for added support. I am not sure if that holds true for the stronger schedule 80 PVC (gray color) but you could check. I think if necessary, you could modify your existing desigh buy simply cutting the PVC half way between the joints and inserting the next size down piping, then glue it back together with slip joints.

Great ideas, guys! I'm going to go to my hardware store this weekend and get some wall brackets and some PVC reinforcements. It is already leaning a little because the floor it is on is uneven, so that concerns me. I'm going to try bolting it to the wall studs first...I'll let you know how it goes.

I use rebar inserts for PVC piping as well Tracy. Little more expensive and makes the structure a bit heavier. A gallon of wet vermicompost weighs about 8.33 lb/gal, so be careful.

Is this inside your climat controlled home? I'm wondering what this will do to your himidity and will that throw off the HVAC system, especially when running th AC.

I've been thinking i need to expand my system to keep up with my cooking style( almost vegitarian and make almost everything from scratch). I was thinking aboit two more worm inns. My inn has been going through a lot of water and I have been wondering how much water three will put in the air.

Mr_yan this is in an old, unused cottage that used to be a rental unit but is now unfit for living. We mostly use it for storage, and there is some concern about increasing moisture levels, but I just leave all the windows open and don't worry about it. The worms are all in one room, the stored items are in another.

Different materials may allow the bin to dry out more or less quickly. I almost think the bins mentioned here maybe are using a material that has more air flow through the material than the ones sold. Thus the great quantaties of water evaporating from them. But maybe things are composting faster with the more air. Maybe the material is like those clothes sold that advertize "wicking" away the moisture.

I'm a newbie to the Forum, I'm very impressed with your "Mammoth" bin... If I understand the date stamp used by the Forum I believe you posted this information/photos in 2012 I would really appreciate hearing from you as to how "things" are at this point...

Thank You