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 of Bakelite and Elo mouldings, detailing fracture, absorption, and heat resistance.
| Identifier | WestWitteringFiles\G\September1921\ Scan60 | |
| Date | 7th July 1921 | |
| R.R. 285A (100 T) (S.H. 159. 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 EFC. AB.10. 7th July, 1921 X.3513 - COMPARATIVE TESTS OF BAKELITE & ELO MOULDINGS. The two sample coil discs submitted by Mr. Brock have been put through a series of comparative tests as follows. A disc was first clamped on to a bench so that half of its surface overhung the edge, care being taken that in each case the holes in the moulding were in the same relative position. Weights were then suspended in increasing amount until fracture occurred. The figures are, lbs. to snap Bakelite 32.0, Elo 26.0. The broken edge of the Bakelite was of finer grain than that of the Elo. If rubbed together, the black (Elo) was deposited on the brown and not vice versa, showing that the Bakelite is harder. The two halves of each piece, after being weighed, were now immersed in water and oil respectively and left for 95 hours. They were then removed, surface dried and re-weighed. This showed the percentage of absorption to be as below:- Water % Oil % Bakelite. .812 .097 Elo. 2.25 .133 Both water-soaked samples lost a little of their surface finish, but a ridge had formed on the piece of Elo, along the fractured edge. The piece immersed in oil seemed to be unaffected. The two pieces which had been used for the test in water, were now placed together on a plate over a gas flame, and heated gently until softening occurred. This took place at about the same time with each, but the Bakelite seemed to be slightly softer than the Elo. On further heating, both pieces began to blister and finally to carburize. Held in the gas flame they burned about like wood. The two pieces from the oil test were put in petrol overnight, for about 15 1/2 hours. When removed they were found | ||