Copyright 2006 T. Sheil & A. Sheil All Rights Reserved
Homecasting: A Primer: How I Make My Own!
For homecasting, you
will need:
A place to work. It must be free of obstruction, free of pets and children, free of awkward adults, and free of moisture.
A table on which to work. It should be hard, smooth, and resistant to heat. Hardwood works. Place the pot in the center. You do not want to accidentally tip it or knock it over.
Power – electricity – use cords long enough that you do not trip over them. A trip can pull the pot over, spilling molten metal.
Protection: safety goggles, welder’s gloves, long sleeved shirt. Also keep a bucket of sand on hand to handle fire or heat problems.
A cheap knife and thin screwdriver to open the mold. Get cheap ones, since they will only be used for this. Save your good tools for real work.
A stirrer, preferably a steel or iron bar with a handle. The handle should not conduct heat. Wood is better than plastic for this tool. Plastic melts, and might get loose if the bar gets too hot. It should be 7 to 12 inches long. (That’s 175 to 300mm for the Cro Magnons who use metric.)
A cheap pliers to help pull figures from the mold. A cheap, sturdy needle nose helps pick out small pieces of metal.
You need a ladle. A small ladle is essential. Not too small!
A clipper to help trim figures.
Files, including a rasp, for removing plug ends and flash Get cheap ones.
Clamps to keep the molds closed. I used the spring-loaded ones that look like pliers. (Warning – plastic clamps cannot be used with metal molds – they will melt. Use plastic only on silicon, or if you have a wedge of thin wood as a heat buffer.)
Graphite. I use the Frankford Arsenal spray graphite.
Sheet metal. A small metal sheet is good to have under molds that do not have a bottom such as older metal molds. I drop a little molten metal on it to heat it before I begin pouring.
I also keep a sheet of metal under the hot pot . It covers most of the work table. Mine is 4’ by 3, the metal covers about 2.5’ by 2.5’ I use aluminum, since it conducts heat slightly less than steel. Aluminum also cools faster.
A note on pots: I had the old palmer pot years ago. If I had the chance, I would get one again. The pot I have is a Lee precision loader with a bottom spout. While spout pours works for some rubber molds, they are a poor choice for metals molds. Thus, what I do is hold the ladle in the top of the pot to keep it as hot as the metal. Then I pour into it from the spout. That gives me enough time to pour from the ladle into the mold. The ladle pour has to be fast!
An important technique of casting is that you have to pour quickly. The speed of a pour means there is weight behind the flow of liquid into the mold. This helps force the molten metal into narrow places and into raised parts of the figure. Once poured, tap the mold gently – a few taps or even vibration help it get into the crevasses.
Metal molds need to get hot. One of my tricks to heat a three-cavity metal mold is to pour slowly into the outer cavities, then do a quick pour to the middle one. The middle figures usually comes out okay. On the next pour, the mold is hot enough for better figure quality. Of course, a little tapping helps.
Silicon molds are usually hot after one pour. Do not overuse. If you pour too often, you can burn out a silicon mold.
Most silicon molds come with fiber board pieces to place on each side while you clamp. Use them. If the mold is warped from heat and does not fit the fiber board snugly, then set it aside for a while. It is too hot and in danger of being burned out.
I like to use three clamps for silicon molds. I use two on the bottom and one for the top. After a couple pours, some silicon molds will leak from the side or bottom. Using two clamps keeps them firmly together, preventing leaks.
When you remove figures, allow them to cool. Just because they are not molten does not mean they are safe. Do NOT drop them into water to cool the, because they are still hot enough to cause a burst. I drop mine onto dry sand.
To save metal, clip off big pieces of excess, such as from the pour spout. Leave a little on the figure – you can file it off later. If you cut too close to the figure, you can damage it and remove some details.
Skim the top of the pot occasionally and discard impurities, also known as “slag.” Pour the molten slag onto your dry sand. Later, when it is cool, discard it. You cannot reuse it for anything.
Safety:
Do not wear loose sleeves!
Do not reach over the pot.
Do not put your face over the pot. Fume are bad. If you sweat and a drop hits the pot, you might get a splatter. When liquid hits molten metal, the effects can be explosive.
Use ventilation. I do mine in a garage with a small fan blowing.
Do not allow any liquid near the work area. If you want to drink something, keep it away from the work area. Better to walk a few steps to drink than to bring your drink anywhere near the work area. A few drops of soda or coffee can be a disaster.
When your figures are cool, you can finish them. Trim off flash. You can use a small pocket knife for softer alloys. I use a knife with a serrated edge because it allows me to trim flash better. Most flash is narrow enough to fit into a serration.
Use a clipper to remove big chunks, and use the knife to trim small ones.
Use a rasp to remove big chunks of flash, such as pour spots. Follow up with a small file to smooth it and preserve fine details on the figure.
A regular file can be used to follow up, after you cut away flash with a knife. I have a set that includes a flat file, triangular file and round file. Do not use hobby files, as they will get ruined with soft metal glomming the grooves. Use regular files from a hardware store. Cheap is good. To clear soft metal out of grooves, use a wire brush. Do not use good file. There is no sense ruining good tools. Buy cheap ones, as you may have to replace them eventually.
Soak figures to remove any solvents and impurities. I drop them in paint thinner for about 20 minutes, and then follow by soaking them in water.
I use Rustoleum Clean Metal Primer. It is white and dries well. Being fussy, I let them dry overnight before any further painting.
A rotary tool such as a Dremel is great. I use a small drill bit and Dremel to make holes to insert weapons, plumes, etc. The various files and bits can be used for smoothing, gouging, etc. If the drill bit or metal it gets fouled with soft metal, try this: take a sliver of pine, like a piece if 1 X 2. Drill into it a few times, or run the bit against it. Do it at high speed. Do not worry of the wood gets hot and turns black. By then, you can stop. The wood serves to remove the metal from small drill bits, other metal tool, bits, etc. This does not work for the sandpaper or graphite. It has partial success on stone bits, such as ceramic.
Remember, if a figure gets broke, or mold poorly or is otherwise ruined, you can always melt it down and cast another one. If it is painted, just use a wire brush. You do not have to remove it all. The heat will burn off paint, which can then be skimmed from the pot.
There are two kinds of rubber molds. Casting Inc sells the red rubber ones. Prince August sells black rubber ones. There is a difference. When Prince August molds get hot, they smell like old tires. They tend to be stiffer than red molds.
Keep your liquid metal at 650 degrees F or less. Use alloys that melt below 650 F. Anything higher can damage metal molds. The lower the temperature, the less wear on metal and rubber molds.
Depending on your alloy and the miniature itself, you can average 7 to 12 foot figures per pound. For instance, we get about 7 or 8 Lone Star paratroopers per pound. Our medieval knight yields at least 10.
Be aware of a problem with molds where the pour goes onto the figure’s head . If you trim at the very bottom of the pour cone, you will likely lop off part of the head. Some of these pours were not engineered well in the first place. Cut about 1/8 inch above the end. This way, you do not cut into the head itself. The remaining piece is small enough to file to shape. This is a problem with some of the metal molds and a few silicon ones, such as the Castings Coldstream Guards and Scotsmen.
By all means, acquire the extra weapons molds if you intend to do conversions and original work. The Castings Civil War mold is great for doing 19th Century figures. This also goes for the two weapons molds for the Castings Coldstream Guards. They provide several arms that can be used for easy conversion work. The Medieval Weapons is useful, as several of the casting silicon knight molds do not do a good job of producing the figure’s weapon.
Prince August has a mold of spare heads that can be used for 19th Century figures. It includes an officer’s cap, cork helmet, spikes helmet and a couple others. Nice if you can get one. They usually sell it with one of their “headless” Coldstream Guard type molds.
