I decided to build an actual dust collection for my tablesaw and jointer. I used some scrap 4" PVC pipe. I cut into the pipe about 1" deep. Then I took it into the kitchen and heated it up on the stove (of course I waited until the wife wasn't home!). I slowly heated it and bent one tab at a time (be careful because the PVC can burn easily). How're I realized that the pipe wanted to go back to being straight when hot. So when I bent one tab, I had to go back and bent a few tabs before. Once everything was close to being completely bent, I heated the whole pipe and put some weight on it to let it cool with the tabs fully bent. I screwed it to the plywood enclosure I made and caulked it to make it completely air tight. It took me about 2 hours to build two of them.