I haven't made a baffle yet, but look forward to getting the dust in my little shop under control. Is it possible to put a heavy gauge plastic trash bag inside the trash-can?
Yes, but you'll need a liner of some kind to prevent it from being sucked up into the separator. Some folks have used a second trash can with the bottom cut out so it can be removed without having to empty the bag. There are some old posts that have some other methods, but I'm not sure if search will find them or not.
Another possibility is to connect a vacuum line to the collection canister, to create a vacuum in the space between the canister and the outer surface if the bag. That should resist having the bag being sucked in.
Grizzly has designed this: http://cdn0.grizzly.com/manuals/g0440_m.pdf (http://cdn0.grizzly.com/manuals/g0440_m.pdf) so apparently it works.
Thanks for the bottomless can insert idea, and the link to Grizzly. I had a similar hookup on an Oneida (mini) Dust Deputy with my (very noisy) shopvac, but wasn't sure if the same approach would work with a much larger dust impeller motor. Can inside the bag inside the can is simple enough.
This works and you have to select the two cans so they are reasonably the same. The plastic bag has to be sized so that the flappy bit that has not been trapped cannot get within 3 or 4" of the gaffle. Still need to wear a mask when changing the bag. Let us know how you get on.