When I started Keramicalia I wanted it to become the place where all the interesting enquiries end up. After 20 years it has got there, and I am very happy, Keramicalia may be a commercial disaster, but we sure have a lot of fun. This is the way I wanted it.
My wife, Judy just looked over my shoulder and pointed out that my title is her saying. Yes she is the master of “Making it Happen.” She has a Range Guide troop, and one day she announced that we were all going to Switzerland for a skiing holiday. The parents thought she had “lost it”; I personally thought she had finally bitten off more than she could chew, but sure enough she got us there. Eleven girls, my whole family and a few other parents. It was the most awesome holiday. Yes it was a lot of work, some inventive fundraising, but it was unwavering, focused effort for a couple of years, and nobody regretted it. If you focus on your goal you get there. You lose it when you take the line of least resistance.
We have brought up our children in this culture of making it happen. Gina is now a trauma nurse, working on a ship doing a world cruise. John is going to China in May to film driving a convoy through China, India, Pakistan the Middle East to Djibouti, Ethiopia, through Africa ending back in Northcliff. Christopher has just come back from the USA where he spent his varsity holiday working in a shop, then checking out Washington and New York with his earnings. Nikki is having a ball with her gap year at a school in Southampton. I am so proud of all of them.
One of my most irritating saying is “Why put off for tomorrow what you can just as easily do today?” I am not good at that one, but at least I try a bit to strive towards it.
So think about what YOU really want, not what society expects of you, and go for it NOW.
Kerasic is our alumina bonded silicon carbide material. The “sic” comes from SiC, the chemical abbreviation for Silicon carbide. The” Kera” is because I am not very imaginative and call most of the things I make Kerasomething or other. (None of my kids are Keraanthing) kerasic is a fine pourable material and lends itself to very complex and intricate castings. It is used mainly for thin walled castings, for example, sintering trays, thermocouple sheaths, elements sleeves lances and fluxing tubes, thin walled crucibles, furnaces muffles, heat radiators, element cages and distillation columns it is also extremely strong. The items above are all small sophisticated expensive pieces and the cost of the material; R45/kg is no problem.
Gideon Kriel of Gee Kay Industrial Ceramics was a pioneer in the use of Kerasic and made some remarkable items. Hennie van der Bank of Quarlcor got rapid casting down to a fine art, and could turn around moulds in 20minutes!
Jay Lloyd of Fornax pioneered Kerasic as a die-casting material. He was casting items in a R10 000 steel die of 2 cavities. With Kerasic he made 24 spin casting moulds at a cost of R6 each. The high thermal conductivity of kersic is good for die casting, also the fine surface finish and thermal shock resistance. Jay then started making thin walled crucibles. Because of the high strength, they do not have to be as thick as graphite crucibles, so you get faster heat transfer. Jay’s sidekick, Peter has invented an ingenious machine for moulding and stripping them. The three wise men of the gold industry have been doing ground-breaking work on composite castings using strange bedfellows such as kerasic and cellular insulation materials, also Zirconiaflow and Kerabrade C and Keratab Ultrafine. They have had some magnificent results. Of course I always want to cut them up to see the interface. Some of them don’t work at all on paper, but work brilliantly in practice. Now they can have their cake and eat it, a single component can be pyroplastic at one end, strong in the middle and insulating at the end.
Currently the crowning glory of Kerasic is Jay’s Element Cages. These are the most intricate castings I have ever seen. When he conceived the idea I told him it was impossible. But as Gideon says, anything is impossible until someone has done it. Element cages are shaped like squirrel cage and hold elements in place while hardly impairing radiation, and with almost no thermal mass. Take an element cage, wind an element into it, wrap it with fibre blanket, clad it, insert a kerasic crucible, connect it to 220 volts and you can melt 2kg of aluminium in 20 minutes . I have been working on a Kerasic pump for molten aluminium. I had problems in some areas. I believed it would be impossible to machine Kerasic, but Danie Wilkins of the CSIR proved me wrong! He has made some components of unbelievable precision.
We have got the volume stability remarkably good, and we can now cast 2 metre rods at 19mm thick. We have one 4 metres long now, still in the mould. I need to build a kiln to fire it as it passes through vertically.
Silicon carbide is a remarkable material. Diamond is the hardest natural mineral, 10 on the Moh scale of hardness. And corundum comes second at 9. ( That’s where the company “Moh 9 got its name. Silicon carbide has a hardness of 9.5. It is therefore the first choice for abrasives, not being as expensive as Diamond.
The other superior it has is its cleavage. It breaks with sharp edges. I am having difficulty getting facts and figures for this article, because silicon carbide does not occur naturally, and is therefore not found in any of my mineral reference books. It is not likely to be found in nature, as its synthesis requires the equivalent of long standing bolts of lightning. *Silica and carbon are placed in a long pile and an enormous electrical current is run through it for days on end. The result is a fused but porous mass of large silicon carbide crystals. The electricity consumed would make even a submerged arc furnace operator cry. The lump gets sorted into green silicon carbide from the centre and black from the outside of the pile. Next the material gets crushed. In the process, the silicon carbide removes a lot of the metal content of the machinery! Now it gets screened these sharp particles are difficult to screen, and abrasive manufacturers always use single sized particles, so that there are gaps between the grains, otherwise grinding wheels would not work. This gives the producers a major headache, because they may have 20 customers wanting 50 to 60 mesh and nobody wanting 60 to 70 mesh. It all adds up to make silicon carbide rather expensive. For sub micron material I have paid as much as R80/kg. Silicon carbide has an enormously high thermal conductivity. Pure crystals have a conductivity of 84 Watts per metre Kelvin. The highest of common Refractories is magnesite, with a measly 4W/mK. Yet fused magnesia is used as the isolator in stove and kettle elements. Why not silicon carbide? Well it is also electrically conductive. This makes it suitable for globar elements. Wonderful things, but pricey. The other property of silicon carbide is its high surface tension. It is not easily wetted by liquids. This makes it difficult to formulate pourable refractories, but makes it perform superbly in molten metal contact situations.
*Frans Nyikos recently gave me a book on silicon carbide which records a few small natural occurrences
For sale 5 cubic metre kiln belongs to Grob ceramics, now retiring R100 000
I want second hand and scrap kilns to repair and sell
3 000 insulation bricks, 1400°C @ R20ea
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