I use wire ties to hold the top down firmly on the uprights. I also used one large tie on the bottom where the bars cross each other. I then used rubber bands looped on the sides and then attached to the zip tie on the bottom. This guarantees the doors always open up. My son has been using this trap for the last two years and he loves it. He catches loads of crabs in it. Last Sunday he had 7-8 large dungeness in it all about 5 inches . Sure no keepers in that one but dang it was impressive seeing almost no space for any more crab in it. Good bait makes any trap work better.
Fairly easy to assemble once you get one finished (definetely use wire and not twine.) Worked pretty well using them for the first time. Sometimes they don't close properly but that could be from wind and or tide conditions and how you pull them up. Caught some crabs, not a bad product.
I had to make a lot of changes to this unit like adding weights to keep it down and made a cage inside for the bait. It did not hold up to the waves on the pier and kept getting trashed around and the trap would collapse due to poor craftsmanship.