From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Comparative tests on insulating materials Elo, black Mouldensite, and brown Mouldensite.
| Identifier | ExFiles\Box 39\3\ Scan200 | |
| Date | 10th August 1922 | |
| COPY. EFC. PB.45 Aug.10th. 1922. TESTS ON INSULATING MATERIALS. The following comparative tests were carried out on specimens of Elo, black Mouldensite and brown Mouldensite Three tests were made:- 1. Hardness. 2. Amount of water absorbed. 3. Effect of high temperatures. (1) By cutting, and rubbing the different samples, one against the other, Elo appeared to be harder than black mouldensite, and black mouldensite harder than brown. (2) The three specimens were then immersed in water for 140 hours, their weights being taken before and after immersion with the following results :- Specimen. Wt. before. Wt. after. %Increase. Elo 9.13 grms. 9.22 grms. .986 Black mouldensite. 5.45 " 5.50 " .918 Brown " 8.55 " 8.62 " .819 (3) Generally, their behaviour on the heating test was as follows. They commenced by a greasy vapour forming on the surface, as though some resinous substance in the material was being melted and was oozing out. At the same time the specimen got a little softer. As the temperature rose this substance expanded under the surface, forming blisters. After a time these blisters cracked and the specimen began to char. When cold it was found to be dry and more easily broken, while the grain of the material at the break appeared to have become much coarser. The temperatures for the various conditions of the three specimens are as follows :- Condition of Material. Elo. Black mouldensite. Brown M.{Mr Moon / Mr Moore} Vapour formed and From 185°C ---------- 170°C ---------- i.e. 126°C material softened. To 271°C ---------- 280°C ---------- 230°C Commenced to ---------- 236°C ---------- 240°C ---------- 228°C blister. Commenced to char. ---------- 277°C ---------- 292°C ---------- 345°C | ||