Datsun Roadster Forum-311s.org

Sound deadening material should ideally be affixed to the metal as it is generally designed to not only block sound transmission but also change/dampen any resonance in the metal panels themselves. Attaching to the back of the vinyl/board would only be doing half the job.

You don’t even have to glue, in my experience. I just put the panel down, lay the foam on it a little oversized then start pulling the vinyl and stapling. Cut the tabs first or as you go. If not tight enough or you make a mistake, undo the staple and adjust. A thin foam sheeting is all you need.
If cut correctly even the clips aren’t really needed, the panel stays or needs just a few clips.
Linda

Thanks for your help in your response, I appreciate it jt as well as others. I have another dilemma, I need the pattern to make the new panels, I need it for the panels under the dash as well as the panels behind the seats, the left and right sides of both. Does anyone have a template of them ? I have a 1968 2000

Tony

the panels UNDER the dash, aren't strictly 'panels' like the rest of the interior. The 'panel' under the left side is a 'formed' piece like the glovebox door, so you can't create it like the rest. Of course, since it is hidden, it is a) somewhat unnecessary and b) irrevalent. No one but you will know that it isn't there.