Technical Change

It will be easier to chronicle the history of Richards Tiles from 1948 to 1968 if I first mention what I consider were the company’s main technical contributions to the industry over the period. They were:-

a) the introduction of mastic fixing of ceramic tile.
b) the introduction of an inexpensive non-contracting “one size” white tile body.
c) the use of spray drying to prepare tile granulate
d) the replacement of flint by Derbyshire sand.

(There were, of course, many non-technical contributions but they are outside the scope of this article.)

Mastic Fixing. In 1948 ceramic tile was fixed to both wall and floor by sand and cement mixes. It was a messy operation and demanded the skill of professional tilefixers. In 1949 my boss, Lawrence Bullin, toured the USA with his co-directors Geoff Corn and Brabazon Ellis. They visited tile plants, our agents and major tile fixing contractors. They came across a fixer in Texas using a rubber based adhesive instead of sand and cement. His peers considered him to be slightly eccentric. But an idea was born. Back in UK Richards tried to persuade the manufacturers of rubber based products to co-operate with us to develop mastics for tile. Most were not interested. Dunlop and 3Ms showed some interest but did not proceed. Our fellow tile manufacturers were not prepared to work with us. They thought that making tile-fixing possible for “any Tom, Dick or Harry” would lead to bad work and alienate architects, tile stockists and fixing contractors. We eventually teamed up with Evode of Stafford and the rest is history. It was a hard slog for about six years. “Richafix” products then began to change the tile fixing scene. Our fellow tile manufacturers now wanted to get in on the act, Richards agreed, and Building Adhesives was formed to serve the UK tile industry.

Non Contracting Body. Traditionally formulated ceramic tile bodies contract during the firing process. Bottle ovens and tunnel kilns had inherent variations in firing temperature. This caused variations in fired size, which necessitated grading tiles by 1/32^nd inch increments. A nominal tile size, such as 6 by 6 inch, would be supplied as one of five 1/32^nd inch grades. The stocking problems, and the logistics of having to keep only one size grade for each installation, were formidable. Some tile companies in the USA had formulated non-contracting tile bodies by the use of very expensive ingredients not readily available to UK manufacturers.

Both H&R Johnson and Richards Tiles formulated non-contracting bodies by an addition of the relatively inexpensive material, limestone (calcium carbonate). The change to non-contracting bodies took place in 1954 at both companies. I now personally admit to a simple form of industrial espionage, whereby we took pieces of unfired clay tile from our competitor’s shraff (scrap) tip. These were fired and measured so that we knew what he was up to.

The simplifications brought about in both companies by the non-contracting body were many and various. Tremendous benefits accrued.

The Use of Spray Drying. The traditional tile body mixing process made the ingredients into a slurry from which water was removed to yield a granulate of about 5% moisture content. As much water as possible was removed by mechanical means and the obstinate remainder was removed by heat. Mechanical removal was much less expensive than drying by heat. Spray dryers remove all the water by heat and did not, therefore, seem to present a viable alternative to the method being used.

However, in 1961, together with Martin Graham and Derek Weston, I visited the Sphinx and Mosa tile companies in Maastricht, Holland. At the Sphinx factory we saw a miscellany of tile presses, all using the same granulate. The received wisdom of the day said that this was not possible! Each type of press needed a unique granulate specification! The Sphinx granulate was being provided by a spray dryer. How was it catering for disparate presses? The answer was to be found in the granulate form of hollow spheres. Those spheres flowed like ping-pong balls when fed to the press die cavity and so gave consistent and uniform die filling. Traditionally prepared granulate had flow properties more akin to those of wet sand. The improvements in productivity and reduction in losses far out-weighed the extra drying cost.

I was keen to pursue the spray dryer route and Sphinx was keen to sell “their” technology. However, it was revealed that Dorst of Germany had supplied the original equipment. Sphinx had modified the original, but the basic plant had been designed and constructed by Dorst. Spray dryers were being used in other industries, notably for powdered milk, but needed adaptation for the ceramic industries.

My wish to change to spray dryer technology was not supported by my colleagues. One reason was that, during the aforementioned visit to USA in 1949, three of them had seen a spray dryer plant in use at Gladding McBean, Glendale, Los Angeles. It was not working properly, never did and was abandoned. There was no successful spray dryer in the ceramic industries, other than the one at Sphinx and some small equipments used for spark plug manufacture. I had to wait but, fortunately, not for long.

Georges Philipou of Thessaloniki, Greece wrote to me in 1962 suggesting that Richards Tiles and a company he had formed should collaborate in making tiles in Greece. (Georges had been a ceramics student at Stoke Tech. 1952/1955 after graduating at Brussels University and had worked at Richards during a summer vacation.) Andrew Corn and I went to Thessaloniki, reported favourably, and it was decided to go ahead. Georges was also of a mind that spray-dryer technology was to be the way forward. Dorst had, by this time, installed a spray-dryer at Steulerwerke tile in Germany which Georges and I visited. I was later told that factory owner became so proud of it that he installed a hotel lift alongside to convey visitors up the drying tower in style. Our decision to go ahead was based on more pragmatic reasons and the spray-dryer at Philkeram-Richards, Thessaloniki was the first in our group of companies. Not long after, we installed a much bigger one at Minton Hollins, Stoke. The works manager, Doug Rushton, loved it for the improvements it brought him. The technology is now universal. Twenty years on, in 1984, I was working with Elmer Salgo, Chairman of Intrkiln, USA. I learned that he had been involved in the pioneering work at Gladding McBean. The following year, 1985, I visited the Franciscan factory of Josiah Wedgwood & Sons in Los Angeles. During conversation it transpired that we were on the site where the original spray dryer work was done and I inspected the remaining concrete base.

The Replacement of Flint by Derbyshire Quartz

Silica is a major constituent of ceramic bodies and in North Staffordshire silica “flints” were the source. Flints came from beaches in the south east of the country or as a by-product of the cement industry. They were first calcined, usually between layers of coal, crushed and then water ground to a water slurry. Burslem Mills, Federation Road, Burslem carried out this operation but this unit was in need of renewal. It was going to be expensive and this made me receptive to ideas from Bert Smith, General Manager of British Industrial Sands, Oakamoor. He was supplying the glass industry, notably Pilkingtons of St Helens, with white quartz sand. He had attempted to promote sales to the North Staffs ceramic industry with no success. In fact he could have written a book of reasons given to him, detailing why flint was unique and irreplaceable in the local ceramic industry. However, we at Richards Tiles foresaw the Factory Inspectorate becoming increasingly dissatisfied with Burslem Mills. We had an incentive. BIS and Richards co-operated during 1967 in a programme of work at Oakamoor and Tunstall. This resulted in the replacement of flints by calcined Derbyshire sand in the first months of 1968 at all Richards factories. We had not foreseen that a serious shortage of flints was to arise by 1968. We merged with H&R Johnson in that year and it was both a surprise and a relief to them to learn what we had done. I went to a European Ceramic Congress in Spain with Roland Shipley, General Manager of HRJ, in July 1968. He had arranged for industrial scale testing of the Derbyshire quartz at one of the Johnson factories and the results were to be telexed to him in Spain. He pushed a note under my bedroom door. It read; “Received results. All is well. See you in the bar. Drinks are on me.” I was relieved. I had started to wonder if there was a “unique” factor we had overlooked.

previous: Technical societies and ceramic education
next: summary of 1948/58

Ken Green
June 2001