We used the same PVC furniture grade pipe and fittings that we sell to our customers, to make sure that they are as good as manufacturers claim they are!
We used our white furniture grade pipe for the frame of the light tent, with three-way and 90° elbows to join them together. We dry-fitted these joints (meaning we did not glue them together or use rivets or self-tapping screws) in case we ever need to move or alter the tent in any way. While the joints are not permanently held together, they are still strong and have not moved since we built the tent months ago!
As for the material you can see over and around the tent, we attached this to our pipe using the snap clamps we sell! These snap clamps are made of the same material as Lego®, which means they retain their shape no matter how many times you clamp them on and take them off again! They grip the material to the pipe with no room for movement, so you don't need to worry about your material coming loose at all.
Overall, we agree with manufacturers about furniture grade pipe and fittings' strength and ductility! We used our own products to make this light tent and have had no problems at all!