BLUEING STEEL

Reply to a query in May 2009 edition of Contact.(ISSES Magazine)

In 1984 when I started on the small task at Ellenroad I had to make a lot of decisions about the parameters I should set for the refurbishment. One of these was to decide what to do about the blued steel cladding on the cylinders etc. made and fitted by Kenyon’s of Dukinfield in 1919 when the engine was altered by Clayton Goodfellow to a double tandem. In the seven years the engine had stood idle and largely neglected rust had started to attack the cladding. The question was how much we should do to it.

I had the luxury of unlimited labour thanks to that finest of all subsidies to the Heritage industry, Manpower Services. I decided that the best thing to do was clean it thoroughly, see what it looked like and make a decision then. I have always liked Scotch brand abrasive plastic mat and it just so happened that a friend of mine John Ingoe at Rochdale Electric welding was doing a boiler repair at a factory that made the material. He had a word and got me two large cardboard boxes of off-cuts and sub-standard cloth. I set the lads on. The first thing we did was soak all the surfaces with a very thin protective and penetrating oil made by Century Oils; Centigard. Once it had all been soaked the lads started rubbing the blueing down gently with the finest grade of the material, I made quite sure that they knew that the object wasn’t to get the rust off, just attack it gently and then clean off, oil up again and move on. By the time they had been round the entire engine about four times the results were beginning to show and we found that there was more of the blueing left intact than we had thought. The end result isn’t the startling blue of the original cladding but a very acceptable blued finish with some patches more worn than others but burnished to an acceptable finish.

There was only one slip-up. I went on holiday for a week and one of the lads got a touch over-enthusiastic on the right hand HP cylinder cover. It was very rusty and he polished until it gleamed! Problem was there was nothing left at all only brightly polished metal. I forgave him because his heart was in the right place and it certainly looked smart and clean. If you go to Ellenroad and have a look you will see what a good job the MSC lads did.

As for how the blue plate was manufactured. I have little doubt that the origin of the treatment was the blue finish left on cutting tools and springs after heating and quenching. Not surprising then that most of the blued plate was made by heat treatment. I was told by a man who used to make it that they polished the steel, then pickled it and then laid it on a tray of hot sand and watched while the colour built. Once the desired shade was reached the plate was slid off the hot sand bed straight into a shallow tank of sperm oil which quenched it and fixed the colour. I checked this oral evidence by looking up blueing in Osborne’s invaluably ‘Encyclopaedia of the Iron and Steel Industry’ and he concurs. He also mentions a similar process for continuously blueing iron strip by passing it through a bed of hot sand and then into the sperm oil. The entry also describes the various chemical processes used to obtain a similar effect. I have blued small steel pates myself in the workshop using the sand bed and I can report it is quick, cheap and effective, the secret is to get the plate perfectly clean and grease-free before heating. As for the use of the material, I have only seen it bent on large radius surfaces. Where a more acute angle would be needed they cut the sheet to butt cleanly on the angle and then finished the corner off with light brass angle strip secured by captive ¼” brass Whitworth round headed screws mating with captive nuts soldered on the back of the plate. You could form it down to about two inches radius without any obvious damage to the blued surface. Some smaller pieces may have been formed before they were blued.

My father used to work at Armstrong Whitworth’s in Trafford Park and they used large tanks of whale oil as a quench when heat treating large gun barrels. He fell in one of the tanks one day, luckily it was not hot. He reported that his skin was as smooth as a baby’s bottom for weeks afterwards but he stunk terribly!

SCG/07 July 2009


Stanley Challenger Graham




Barlick View
stanley at barnoldswick.freeserve.co.uk