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).
Cost and time analysis comparing oil resisting cellulose paint with linseed oil for sealing aluminium castings.
| Identifier | ExFiles\Box 148\5\ scan0357 | |
| Date | 1st July 1938 | |
| To...By & Rm.{William Robotham - Chief Engineer}........From RHC{R. H. Coverley - Production Engineer}/RWE. RHC{R. H. Coverley - Production Engineer}/RWE.3/MC.1.7.38. OIL RESISTING PAINT The present procedure at R.R. of spraying aluminium castings with Linseed Oil in order to seal the pores of the metal is very costly, as it entails a 2½ hour baking period; and other incidental charges which cannot be accurately assessed. Other firms, such as the Rover Motor Co., spray their cast iron crankcases with an oil resisting cellulose, which fulfills the same purpose and does not require baking, since the paint is quick drying at room temperature. The oil resisting cellulose used by Rover's is supplied by Messrs. Docker Bros., Birmingham, who have every confidence that this product will be just as suitable for aluminium as cast iron. We have, therefore, sent to Docker Bros., two small aluminium castings for treatment by this process; on return, these samples will be submitted to the laboratory to test adhesion and sealing properties. Further, we propose to have a Bentley top and bottom half crankcase cellulose sprayed and sent to the Experimental Department for actual running tests. The colour of this oil resisting cellulose would be blue-grey, as distinct from the red used by Rover's, Vauxhall's, etc. Should the above tests prove satisfactory the estimated saving through elimination of the baking period and the second sprayed coat, would be as follows :- Cellulose Linseed Oil Time taken to spray all parts on one engine with (one coat of cellulose 35 mins. (two coats of Linseed (Oil................... 120 mins. Cost of Labour..................... 1/0½d 3/6d. Cost of (¾ pint of Cellulose at 16/- (per gallon.................. 1/6d (1½ pints of Linseed Oil at (2/9d per gallon........... 6¼d Additional (150% overheads for (cellulose.............. 2/6¾d (Linseed Oil, includes (baking cost............. 6/3½d ---------- ---------- 5/0¾d 10/3¾d Continued....... | ||