It feels like the flap is rocking inside the air chamber when I push down on the spring handle. Maybe the flap is not laying flat when it's at the static position. IDK. I seem to recall that the flap is wedge shaped with turned up edges and welded at the corners to form an open top. I was looking up in there with a mirror when I was setting it up because they left about a tablespoon full up blast beads in the air charmers.