Working in the Model Shop Toolroom each individual was responsible for hardening and tempering their own work. Sometimes it was necessary to "case harden" a part, a shaft for instance, which may have to have a hard wearing surface with a soft core, this was to allow the component to withstand "shock" loading. To achieve this the low carbon steel, "mild steel" which will not harden using normal methods due to low carbon content. You would normally heat up tool steel to cherry red and quench in oil or water to harden then reheat to a lower temperature, "tempering", to relieve stresses built up when quenching and this would reduce the brittle nature of the hardened surface. To harden the surface of "mild steel" the component would have to be placed in a box and covered with carbonaceous material, this was then placed in a furnace and brought up to about 900º and the part was allowed to "soak" in the carbonates material for a set period of time, the amount of time determined the depth to which the carbon seeps into the surface of the mild steel. When this process was completed you harden and temper in the normal way thus leaving a hard outer shell and a hard centre.
During the 1960s when we case hardened a small part we used to go into the office and fetch a black tin which contained a small pair of pliers and a white pellet, we then used to proceed to the welding shop where there was a gas and air welding torch. You then heated the part up to cherry red in the flame and holding the white pellet in the pliers you rubbed the pellet up and down on the hot surface until it melted and deposited a film of molten liquid onto the surface. You then reheated the part to make sure the part soaked up the liquid which turned the flame an orange colour after a few treatments of the above, heat treatment was done in the normal way. The crunch of the story is that the pellet was cyanide and I don't think Health and Safety would allow this to happen in this day and age. If I remember correctly the pellet was the size of a walnut and in hindsight could have done a lot of damage if it had been used in an irresponsible way. However I think looking back the blaze way this hazardous material was treated was nothing short of amazing.
The plating shop at ekco was in hindsight a very hazardous place, the various chemicals used and the way they were contained was, I thought, at the time, rather dangerous. The vats of various chemicals that were placed around the shop, most of which were uncovered, enabled the fumes to permeate the whole shop. I do remember when working for my three months secondment in the plating shop, all apprentices were obliged to work in all the various departments for a period of time, each day you would feel a tickle in the back of your throat, which made you cough, and when you think back it must have been the fumes in the air that caused this problem.
Cadmium plating was used quite a lot at the time I "worked" in the plating shop, this stopped mild steel parts from rusting and gave a pleasing finish. You could have two types of finish to cadmium plating, Bright Dip, which as indicated gave a bright shiny finish or what they called passive which the plated article was dipped into a chemical dye and produced a yellow finish.
All parts to be plated were sent to the plating shop and two girls would, what they called, "wire up" each part individually with copper wire so that they could be suspended on rods and immersed in the plating vats. I think the solution in the plating tanks was cyanide and deionized water. To plate small parts, ones that were too small to be wired up, nuts and washers for example, they would be placed in a revolving barrel again submerged in a solution of cyanide and deionized water and plated in this way.
In the plating tanks they suspended an ingot of metal that was to be used to plate the other articles in the tank, then they charged the tank with electricity (high voltage, low amp) which caused small particles from the main ingot to become detached and deposit themselves onto the article to be plated "ion exchange". The length of time and the electrical power used determined the thickness of the plating required and this was checked by an inspector in the plating shop. The inspector at the time I did my stint was Ron Bunce, to check the thickness of the plating the recognised method, if I remember correctly, was to place a drop of Hydrochloric Acid onto the plated surface and see how long it took to burn through to the base metal, this procedure was measured by a time clock and the time took equalled the thickness of the plating, another I thought in hindsight, potentially dangerous practice. The plating shop plated with various materials, Camden, copper, silver etc. With silver plating, because the silver was valuable, it was kept in a locked cupboard for security but on one occasion it was stolen, the management replaced the silver and set up a camera to see if they could catch the thief, after a while they lost the silver again plus the camera, the culprit was never caught.
When the liquid in the plating tanks became exhausted they would collect them into a large vat then this large amount of chemical waste was treated and neutralised, checked and then discharged into the river alongside the plating shop. Again in hindsight an accident waiting to happen and sure enough it did. Due to a misunderstanding the liquid in the large tank waiting to be treated was discharged into the river untreated with disastrous results. The first sign of this accident was small fish by the thousand were seen in the vicinity of the old weir dying on the surface of the river. Because I was a keen fisherman and water bailiff at that time a number of workers reported to me what had been seen, I then contacted my boss at that time Joe McColl and reported it to him, at this time of course no one knew what had happened. The river authority were informed and when they arrived all hell broke loose Their priority was to try to neutralise the cyanide in the river and to protect as much as possible anyone or any animals that could drink the river water. The resulting pollution killed most of the river life and many hundreds of fish and virtually finished the plating shop on the Ekco site.
