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).
Recommendations to reduce corrosion on a float chamber cover by changing the alloy composition or applying a varnish.
| Identifier | ExFiles\Box 76\3\ scan0083 | |
| Date | 26th April 1917 | |
| R.R. 235A (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. BY EP.{G. Eric Platford - Chief Quality Engineer} Works. War. Laboratory. H15/B311218. Re Chemical action on Float Chamber Cover. Further to our note H15/B191218, the following suggestion has been made with a view to reducing the trouble:- The composition of the alloy should be such that electrolytic action will be at a minimum. In order to do this, the composition should be such that a more homogeneous alloy than 12% copper should be employed. For this purpose the 7% copper alloy preferably containing not more than .5% Iron could be employed. Such an alloy should be less porous than the 12% Copper and this is an advantage. As an alternative, the metal we have employed for Condor pistons with favourable results, should be used since it is very free from porosity and is stronger and closer in grain than the straight copper aluminium alloy. S I understand it is practically impossible to be sure that no water gets into the carburetter. This is, of course, the biggest factor in causing corrosion, but it is probable that if a good dope or varnish were used such as celluloid, its effect would be reduced to a minimum. Sodium silicate and linseed oil or varnishes containing rosin are not as a rule such a permanent advantage since they tend to inter-act especially in the presence of water, with the aluminium alloy. It is suggested that we try a special celluloid varnish and also a special alloy such as noted above. Either of these might cure the trouble. | ||