The Pace Armored Car Company of Chicago in 1930 developed a thin multi layer armor for their bank money transport trucks. As with any armored vehicle, weight rises exponentially with protection. They discovered that two thin steel plates of about 1/8 inch would not do the trick in protecting the guards and contents of the trucks from the ever present gangsters. They took the two steel plates, compressed raw cotton between them and then tack welded the plates to thin channel iron around the edges. The resultant light weight armor would stop any known round up to, but not including, a Ma Deuce. This information, with all the drawings and specs, was sent via Diplomatic Pouch to Germany in 1940. In January 1944 the documents were given to Henschel, who were aghast that such information had been moldering in a file drawer for 4 years.

Henschel immediately put an expert staff to work on this novel approach to armor. Raw linen was tried as the filler, compressed to various degrees, but did not work well, the linen apparently being too coarse. Since cotton was hard to come by at the time, certain clandestine diplomatic contacts were used to obtain several rail cars full from Turkey, transported across the border with Greece in the dead of night.

After obtaining the cotton, Henschel again started tests, and found that the principle did indeed work, far better than they had hoped. Two 5 mm face hardened steel plates with cotton compressed between them was the equivalent of 50 mm of standard face hardened armor, they found, at one third the weight. After multiple hits the plates became damaged and would have to be replaced, but the tests showed no penetrations with weapons up to 5 cm.

The next tests were with plates of 12 mm thickness, with more cotton compressed between. This was found to be the equivalent of 70 mm of face hardened armor, at roughly one quarter of the weight. Again, multiple hits would damage the plates, but only high velocity antitank rounds of 7.5 cm or larger would penetrated the armor, that at ranges under 150 m.

Obviously the thicker armor plates with more compressed cotton did not increase the protection exponentially. However, as part of the tests, a crude measuring device was used. Dresden porcelain plates, flat plates sold as tourist souvenirs, were put between the steel plates as a measure of the kinetic energy from the test rounds. To their surprise, the Henschel engineers found that while the plates would shatter from a direct hit at their location, even an 8.8 cm round would not penetrate the combined 2 12 mm steel plates where the porcelain was located. Light bulbs went off in numerous cranial cavities at the same time, and a rush order was put in to the Dresden Porcelain Fabrik for a veritable herd of porcelain plates.

The final experiments found that the porcelain plates surrounded by compressed cotton increased the protection of the two 12 mm plates to the equivalent of 90 mm of face hardened armor plate, at 35% of the weight. Plates with the new combination of porcelain and cotton were rush fabricated, and attached to the test bed for the upgraded main gun system, the venerable Tiger 1.

In the interest of getting the maximum protection of the undisturbed new armor plates, the sides and rear of the hull were stripped of any odds and ends hanging on them, such as track cables, various tools, and the jack. The escape hatch in the turret was welded shut, and the dual 12 mm plates installed on the hull sides, rear, and turret sides. On the front lower and upper hull plates, a much thicker system was used, with two 30 mm plates with the combination porcelain and cotton fillers. The driver vision slot and the RO's machine gun were welded shut and plated over. With the combination armor attached over the existing armor of the Tiger 1, the hull and turret were to all intents and purposes immune to penetration from any known Allied weapon. It was felt that the coaxial MG and an additional weapon to be revealed later would more than suffice for the hull MG being removed.

The plates on the hull and turret sides were made in sections, with reinforced dividers between them. If the plates were damaged, they could be replaced in sections by simply lifting them off of their hanger plates, and a new plate installed. Total weight of the Tiger was increased by 14 tons, but some of this was alleviated by the removal of now redundant systems and the vast improvement of the motive power systems, which will be explained later.