Were German tanks painted their base dark yellow before Zimmerit was applied? ie.; when a chunk of Zimmerit was knocked off, what color was the tank's surface - dark yellow, or primer? Of course, I realize that if the Zimmerit was knocked off by a projectile, that would leave a bare metal gouge.

Zimmerit fell off in larger pieces around the shell hit. From what I've read of posts on this forum, it's primer red under the zimmerit.

Gaz

Factory applied zimmerit was applied over primed metal. Originally, ochre was used as a pigment. That soon ended because of the high consumption of pigment. It was left in its gray/white color and oversprayed with Dunkelgelb.

Hi,

What I see in many pictures is a dark color which I assume it to be the primer. However the zimmerit must a been a very sticky thing, as you always see it leaves residues in its light color everywhere. The effect you have to imagine it is a kind of "fragile" concrete or ceramic material that breaks under impacts and leaves some scorched areas fall apart, others stay. Interestingly in many pictures you see a thin layer of zimmerit stay stick on the primer, while the outer part falls.
Having seen the Panther in Saumur in the middle of the restoration process, I saw original portions of original zimmerit under the sponsons, and their color was a light grey with a beige tinge.
This post should be so much better illustrated with pictures....
Nacho

Zimmerit was made from a base of PVA with the main filler being barium sulfate. Sawdust was among other fillers used. PVA, for those who aren't familiar, is a synthetic glue (think Elmer's glue). Its stickiness, when combined with the other ingredients to make zimmerit, is why it worked.