| Hi Joe,
On my current car and as best  that I can recall from my Triumph youth, 
the sill under the chrome strip was black undercoating. If I'm right it 
was used to resist stone & debris chips. When I refreshed the sills on 
my car I used 3M brand spray undercoat. This product had a low sheen 
appearance & is very durable. It goes on lighter than the inexpensive on 
the shelf products. I was only able to get it from auto body supply houses.
The black line continues straight parallel to the underside of the 
chrome strip to the edge & wraps around the return on the front & rear 
fenders.
-- 
Mitch Seff
Oceanside, N.Y.
75 TR6
http://www.angelfire.com/ny4/triumph5/ 
 |