Alan, as Bill(Squeeze) suggests,if total originality is not a issue,and if you must use silicone,use a glazing silicone, NOT the domestic stuff.
Alternatively, Autozone sell glazing urethane.
The stuff they use to bond windshields into modern tin.(I think theirs is a 3M product)
It sets more like rubber and can be trimmed back when dry.

Last edited by jockbolter50; 11/24/2010 11:05 PM.
1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.