"From the 5 knocked out Tiger tanks and 15 PzIV tanks I have examined, I have established the following:
- All Tiger tanks have their turret sides, upper and lower sloped front plates, side, and overtrack screens covered in a cement-coloured substance, 2-4 mm thick. The substance is applied in ridges.
- Out of the 15 PzIV tanks, two of them have their turret screens covered in this substance.
- Upon analyzing the substance, it was determined that it does not ignite. We have examined a tank that burned, and the substance remained. It was only darkened. When the substance is placed in hot water, it does not dissolve, but becomes softer. It reminds me of caulk, but it is neither that, nor cement. Neither sand nor clay are evident. We need to submit it to laboratory analysis.
Conclusion: I believe that this substance is used to guard the tank from incendiary bottles, and also serve as winter camouflage, due to the gray colour.
The substance was removed from knocked out tanks.
- Burned tank (darkened colour)
- Knocked out, non-burned.
- The substance was scraped off with a knife from the tank's sides."
CAMD RF 38-11369-419
Let's see what lab analysis says.
"To investigate, we have been supplied with two samples: one 12 grams, one 7.7 grams, 19.7 grams in total. The sample is complicated in shape, and, photographed in full size, looks like this:
The bottom side of the sample, meant to face the metal, has a smooth, polished surface. Externally, the sample is dark-gray-brown, light, has small pores, and is rough on the top side.
The micro-structure sample consists of a gray-brown opaque substance, inside of which red-gray-brown polarizing organic substances can be seen.
Inside of these organic substances, there is a large amount of angled fragments and grains, 0.01 mm to 0.1 mm in size. "
I'm going to skip the chemistry (partially because I am not a chemist and cannot vouch for the accuracy of the translation).
- The ceramic substance is a paste, which includes 53% barite, 16-17% quartz, and 27% organic matter.
- The melting point is 1100 C.
The small amount of the sample (about 20 grams) does not allow the examination of the organic substance, or experimentation with its effect when exposed to burning gasoline or incendiary fluid.
The substance's parallel fluting, low melting point, high porousness, etc. lead me to believe that the main purpose is the concentration of incendiary fluids and their extinguishing by the means of the melting of the ceramic paste. "
CAMD RF 38-11355-2219
Of course, the lab analysis doesn't say anything about its magnetic properties, so maybe it still worked in that regard? Well, there are plenty of Zimmerited up tanks in museums. Yuri Pasholok, who is actually allowed to touch them, performed an experiment.
Hm, no dice. It still looks really cool on scale models, though!