On Mon, 22 Mar 2010 04:29:13 -0700 (PDT), the infamous jmsiat
scrawled the following:

I want to make a mould for a clear headlamp cover on a sports car.
The body is unpainted (right now) frp, If I could fill the 'socket"
in the front of the car with an expanding foam and work it into shape
after it hardens then I could get a positive, and then vacuum-mould a
bit of acrylic or polycarb to match. The fellow doing the body-work
and painting would like it very much if this did not ruin his nice
work. If there is not a non-sticky foam then what should I use as a
release agent - could be something as simple as parchment papaer I
suppose...

Is there a foam that would suit?

Any other suggestions welcome.

No, these covers are not otherwise available.

We used to foam parts in place in boxes by
1) spray foam in the bottom
2) put a sheet of poly on top
3) put the manpack radio on that
4) put down another layer of poly
5)spray foam on that
6)close the box.
It filled the spaces and left few voids.

Couldn't you put poly in the socket, add foam, cover, remove it from
the socket, fill voids, and cast from the result?

--
If we attend continually and promptly to the little that we can do, we
shall ere long be surprised to find how little remains that we cannot do.
-- Samuel Butler