When I began at the Science Center foundry, I was encouraged to attempt new things, try out difficult castings, innovate, experiment, in short, go for it. So long as I used my own metal, just about anything was possible so as to expand my base of knowledge and experience. In the foundry, you learn by doing.
It all came to an end in 1998 with a new manager. She did not understand the traditions I had been trained with. She didn't care. Things would be done her way with the handbook of company policy held high as the final arbitrator and interpretation of the law.
I had though we had come to some sort of agreement but that was forgotten or ignored, which I cannot say. The end result is, well, its ending. No more so-called "personal projects." Never mind the experience in the doing that I brought to my job, never mind that audiences thought it was neat, never mind my investment of my own time and money in support of my workplace, never mind how much I loved what I was doing and how that love drive exciting demonstrations. Policy is policy, no compromises, no understanding, no more.
I do not suffer fools gladly. And because of that, eventually, inevitabley, I stepped on her toes once too often and was fired for it.
And so, it begins. Albeit, slowly.
A lot of time has passed but I am slowly making steps towards the production of my own foundry. I have purchased a house and, by a fortuitous coincidence, it has the remnants of a garage or barn in the back yard. As you can see by the picture, it will take a great deal of work to turn it into a workable space (not the least of which is rebuilding the two collapsed walls) but it is likely the future home of Kordite's Metal Things.
If you want to help, I am looking for a used furnace. I prefer operating with natural gas but, rather than running a gas line from the house I'll probably have to settle for propane tanks. The crucible should hold no less than 7 pounds of aluminum. Some Brands and types that are out there: The Mini-Mite Portable Reverberatory Tilt Type Melting Furnace Model F-3, the McEnglevan Speedy Melt C-20 Crucible Furnaces. These furnaces new can run as high at $4,500. With casting tools, flasks, sand, bellows and other sundries running another grand or so, you can see this is not a small undertaking. I have plans for building a furnace from the ground up but would prefer, for safety and insurance reasons, to buy one with the blower and fittings already established, used if possible.
The process I used to make my metal things is called Green Sand Casting. Foundry sand, made moist with water, is packed around a pattern. First one half, and then the other half of the mold is packed in a two-piece box called a flask. The two halves of the mold are separated, the pattern is removed, channels, called gates, for the molten metal are cut in the sand and the two halves of the mold are put back together. For pins or wire backs and the backs of buckles, these bits of metal are pressed into the sand so that the part I want to be imbeded in the casting are sticking up out of the mold so that, when the metal flows into the casting, it will flow around the wire, solidify and hold the wore in place. Using my standard flask for a piece like a Daqtagh or for a group of pins, the entire process will take 40 to 45 minutes and will use around 100 pounds of wet sand.
Molten anuminum, in excess of 1,200 degrees F. is poured into the mold. Once the metal has solidified, the sand mold is broken and the casting is removed. The mold is not reusable but the sand can be re-mixed and used again. Extra metal is cut, filed, or otherwise removed from the casting. The metal is polished with a wire wheel and might be painted.
The process has been used for the casting of metals for thousands of years and continues to be used today. In it's most basic form, a child could do it. In fact, my daughter, 9 years old at the time, has packed a mold.
The short answer is no. I have done a few but the results have been disappointing. The difficulty is in casting something that is so broad and thin. The metal, as it flows through the mold, cools very quickly and has difficulty reaching the very ends of the sword. Then, as the metal cools, it shrinks. That shrinking can literally tear the casting apart. If it doesn't tear itself apart, the tension in the metal produces micro-fractures, tiny cracks that can sometimes be seen along the edge and can be heard as an off-key ding acompanied with an unpleasant rattling when the blade is struck lightly. All this is discovered after four hours of ramming sand and pouring metal.
That's a lot of work for something that has a very poor quality and, with that excess tension, could snap under the slightest added stress. I had two failures before I got one that was good enough to hang on the wall. That's eight hours down the tubes.
If you want a betleH, look at the others page. Get one cut from sheet metal. Casting is not for swords.
Sorry, I don't do rank pins. Their small, intricate design is difficult to cast and I haven't been able to get a decent pattern. There are limits to aluminum casting.
I have a small melting pot suitable for pewter, which would be appropriate for making rank pins but I haven't worked on any patters or made any molds as yet.
It is possible to produce just about anything given a proper pattern. You see, I consider myself less an artisan and more a technician. I can make the casting from a pattern but I don't have the artestry to make a nice pattern. As such, most of my things are copies. The bracer pins. . . they were originally resin and I got pissed when the broke. I copied them in metal so that they won't break again.
So, if you have a design for a pin, weapon or something else you'll need to make a pattern out of a material that is fairly rigid like plastic, wood or plaster.
It will need to have proper draft. That means no vertical edges. As the piece sits flat on the table (although, a curved back can be done) no edge can be closer than a few degrees to vertical. It will need to lift out of the sand without grabbing.
It can't have any undercuts. The mold will need to pull apart in two halves, a top and a bottom.
It can't be too thin. Remember, molten metal is going to be flowing through a mold made of wet sand and will be cooling and solidifying. If the space is too narrow, the metal will cool and solidify too quickly and will not fill the casting. 1/8 at its thinest, I should think. Avoid spaces that narrow and then open up again (like the boom and command pod of a D-7), the metal cools as it flows down the narrow channel and cools even more what it opens up into a larger chamber.
Don't make it too thick. Thick pieces have shrinkage problems that can be controlled in several ways but there's no need to have the piece thicker and heavier than necessary.
It souldn't be too detailed as the casting in metal will wash away the really fine work. I really can't qualify this to tell you how much detail is too much so just make nice, prominent contrasts and we'll see how it turn out.
|http://www.tasigh.org/dochmey/faq.html -- Revised: 19 May 2002
Copyright © 2002 Kevin A. Geiselman