I learned of this, by accident. One corner near the
right front wheel on a work van, was rusting less
than the rest of the the other sheet metal. I noticed
someone before me had foamed it in. I've done this
several times since then, and the foam seems to
slow down the rusting.

..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On 9/18/2013 2:55 PM, Nate Nagel wrote:


I'd be careful using the foam in closed areas of a car body - it's been
done in the past, e.g. the "roll bar" of the Porsche 914, it seemed to
actually accelerate the rust. If you do foam closed areas make sure
they are well and truly closed and that no water is going to get in
there. It can make a real difference in stiffness and noise reduction
though.

nate