Original poster: Tom Perigrin <tip@xxxxxxxxxxxxxx>When thinking about vents, think about deflectors. I have worked in explosives laboratories and they don't try to stop the blast/fragments with solid plates as much as deflect them numerous times until they stop.. I have seen small portable lab shields that consist of multiple layers of mesh, so that any particles entering the mesh get bounced around inside the maze. I have worked in rooms with weak walls backed by a maze of 45 degree deflection louvers, such that the weak wall will blow into smithereens and then be deflected one way by the first set of louvers, another way by the second, etc.. It was gonna be rough on the guy working in the room, but that's part of the profession.
When I do get around to trying coin shrinking, I'm going to be a bit of a naive maverick and try to muffle the sound as much as possible with a sound-insulated over-casing outside the primary containment. It'll be a bit of work, but might be worth it. I like to stay on good terms with my neighbors, and due to a pyro incident in my distant past, I want to avoid anyone calling the cops to report loud bangs associated with me. I'll let you know how well that works out. Fortunately my garage has cinderblock walls, which helps some, although the windows are thin, and the various doors leak sound a bit.
Rent out the space to a punk garage band when you aren't working... and then when you are working, crank up the stereo recordings of their music... heavy on the thump thump thump beat...
Or, take the opportunity to tune your car in the driveway without exhaust pipes ...