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THE STORY OF BAKELITE  

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THE MATERIAL OF A THOUSAND USES

We take modern plastics for granted. Virtually everything is made from them: cups, bowls, baths, drainage, shoes, clothes, handbags, cases for all manner of electronic devices, insulation for electric wiring, boats, CDs... the list is virtually endless. There are many, many different forms of plastic, too. Some that float and make good mooring rope for boats, some that can withstand high impacts and therefore make good beer crates and luggage, some that are ideal for paints, some that withstand the sun's damaging ultra-violet light and are used for double-glazing, some that are highly flexible and are used for sacks, bags and packaging...

It was not always so. Most of the plastics we think are commonplace today did not exist before WWII. Before then, the choice of plastics was limited.

Essentially, there are only two forms of plastic, the most common by far today being the thermoplastic variety, partly because it can be re-melted and re-used. Examples are Styrene, Vinyl, ABS and acrylic. These are relatively modern creations. The other form of plastic is the thermosetting variety - this can only be used once. The application of heat first softens the plastic but the polymers then cross-link and harden permanently. In the hardened state, the plastic produced is generally heavy, rigid, tough but rather brittle. Bakelite (Phenol Formaldehyde) is the most famous example of thermosetting plastic and was arguably the very first successful fully synthetic plastic.

THE PRECURSORS OF BAKELITE

Bakelite phenolic resin was invented in 1907 by the Belgian chemist Leo Baekeland whilst working in New York. He patented it under the name 'Bakelite'. From this it would seem that Bakelite was a product of the early 20th century, and in terms of its success, this is true; however, many experimenters had contributed to its creation, albeit perhaps unwittingly. It was well known that plastics existed in natural form - the natural resin of amber, for example - and during the 19th century, a number of advances were made. Vulcanite (vulcanised rubber) was invented by Thomas Hancock, a British chemist, by adding sulphur to natural latex to produce a tough, resilient rubber. This material found a range of commercial uses, the hardness variable by the amount of sulphur used, to suit items such as tyres, fountain pens and forms of jewellery.

Parkesine, created by the British inventor Alexander Parkes, was a form of cellulose nitrate, itself invented in the 1840s as a highly inflammable material that found uses in the production of explosives. Parkes modified the manufacturing process to produce a stable product that could be pressed into sheet form or moulded into a variety of shapes such as shoe horns, brooches and cutlery handles. He tried to set up an early form of mass-production plant but the enterprise foundered and his company became insolvent. It is fair to say, however, that Parkes can be given much of the credit for our modern plastics industry. 

Xylonite, a similar product to Parkesine, was severely limited by it's inflammability. 

Celluloid arrived next, invented by John W. Hyatt and, together with Charles Burroughs, Hyatt developed compression moulding machinery and pioneered the blow-moulding process. Celluloid was a versatile and successful product with a life from about 1880 through to the 1920s. Although still used in and after the 1930s, Celluloid was by then being challenged by new and totally synthetic forms of plastics. The first of these was Bakelite.

HOW BAKELITE CABINETS WERE MADE

Baekeland created Bakelite by combining carbolic acid and formaldehyde, derived from coal or timber. The brittle resin compound that is the product of this combination is allowed to cool before being ground into powder form and, usually, mixed with fillers such as wood flour (effectively, fine sawdust) or cotton. Pigments for colouring are added at this stage. Catalysts and other chemicals are then added and the mixture heated to create a thermosetting compound that required great heat and pressure to make it melt. Finally the resin compound is re-ground into powder and pressed into blocks known as pre-forms for use in moulding presses such as the Ekco 500 ton hydraulic press pictured here. Inserts such as brass screw retainers may be added to the mould before the pressure casting. Under great pressure and considerable heat the powder pre-forms become a viscous liquid that flows into the steel cabinet mould. The polymer material then forms cross links and sets permanently, retaining the exact contours of the original mould. Removed from the mould, any 'flash' (excess plastic around the mould extremities) is trimmed or ground away and another cabinet shell is completed. Because the original mould must be both extremely well made and finished and also be capable of withstanding the great pressures involved in the moulding process, the work of the mould maker was - and still is - highly skilled. 

The moulds themselves represent a high financial investment and it is only the concept of mass production that make their use economical. As a crude illustration of this, think about a single cabinet produced from such a mould. That solitary cabinet cost the total of the tooling cost - mould production cost - to make. However, produce 1,000 cabinets from the same mould and each will have cost little more than one-thousandth the cost of the original mould. This example is extremely simplified and there are many other factors to take into account if a true picture of manufacturing costs is to be appreciated - but the principle is correct. Compare with the production of wooden cabinets. Each will cost a finite sum, virtually regardless of the number produced (again, in simplified terms). So, 1,000 wooden cabinets will cost nearly 1,000 times more than a single cabinet.

See also 'Bakelite' under the 'Restoration' button

The best website for BAKELITE

If Bakelite interests you, whether radio cabinet or not, a visit to Jools' brilliant site is an absolute must. Lots to read, filled with Jools' infectious good humour together with great pictures. Just the BEST there is. Take a look on the 'links' page for the website address.

 

 

 

 

Ekco: one of the giant Bakelite

moulding presses

 

 

Ekco M23, 1931/2, produced on an Ekco moulding press

 

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