1. OK the funnel end of the water bottles were cut off using a 12" compound miter saw left all the way up. I clamped a 2x6 up heigh against the fence and then another 2x6 piece as a stop block so it could just push the bottle into the blade and rotate the bottle. It worked like a million $$$. The flat end i just used a dremmel routing bit and a large sanding drum to clean it up. I actually used 2 people here, because i had to have some hold the guard up and saw on while i did the cutting.
2.I used (4) 1/4-20 SS bolts, 90 deg apart. I just had to drill that one you cant see with the bottles apart. I also drilled about 6 hole opposite of each other inside so i could use a small bungee or wire to keep the bait in the center.
3. For the door all i had was pretty thick plexiglass/lexan about 1/4". It gets heated in the oven for about 5 min at 350degrees and your cookies are done

. I heated it on tin foil and when you can see it has totally layed down flat on you pan i took it out and laid it on the bottle with 4 pieces of newspaper between the 2. I had to do mine twice and the curve was not good enough for me the first time. thinner plexi will bend easier. In different places i epoxied the plexiglass to the bottle and in a fes spots i drilled and tapped the plexiglass for 10-24 screws to hold the aluminum hinge to it.
If it bubbles it is to hot, there are bubbles on mine as i used 375 and got it to hot the first time.
Lastly the clips to hold the 2 pieces togather i made also out of wire much heavier than coathanger but i will try coathanger next time. I had a piece of scrap aluminum with a square U shape in it and i just layed the wire on top and with another piece of metal and hammer, i hammered the wire into the U shape so all my clips were flat on all 3 side and identical like a staple.
Drilling all the holes took some time because i also countersunk them inside and out. On the next one i am hount to try using a heat gun on them to see if it will smooth them out. You can easily get away with just leaving them as drilled.
FYI, the bottle does sink. I want to say my finished trap is 11.5" x 26"
Thats it , all my secrets until "Super Duper Pooper Scooper Minnow Trap Mark 2", lol. I started drilling holes today. I got 2 bottles without the grab handles, which i like much better.