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).
Continued report on materials testing, comparing the properties of Bakelite and Elo in sulphuric acid.
| Identifier | WestWitteringFiles\G\September1921\ Scan61 | |
| Date | 11th August 1920 | |
| R.R. 285A (100 T) (S.H. 159, 11-8-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2800 -2- Contd to be unaffected. They were now placed in sulphuric acid, density 1350, and left for 24 hours. It was noted that the Bakelite just sank in this while the Elo just floated, showing that the specific gravity is about 1.35, the Bakelite being slightly higher. This treatment seemed to have no effect on either sample. An hour in strong sulphuric acid affected the colour of both pieces, but did not seem to affect the surface. Probably the colouring matter only was attacked. The foregoing tests show that the Bakelite is superior in almost every respect to the Elo, particularly as in the first instance it had a much better finish. It has not been possible to test the dielectric strength of these materials, but in any case, this would seem to be a consideration of minor importance for most of the work for which they are required. It seems quite possible that if the Elo were put under higher pressure whilst in the mould, it would have better finish, and be stronger, denser, harder and less absorbent, thus comparing more favourably with the present sample of Bakelite. It is suggested that the coil disc used in the above tests be made the regular test moulding for comparing various moulding materials moulded by ourselves, especially in the absence of definite measurements of temperature, etc. A sample of Elo, moulded by the suppliers is just to hand. It is noted that this has a smooth finish and fine fracture, comparable with Bakelite. It also just sinks in acid of 1350 density. FJA. | ||