| In Metal Casting, the type of furnace you have at | | | | with the fuel or the flame. This process is also |
| your foundry, or workshop determines a lot of | | | | used in Puddling Furnaces. The name |
| the work you can or can not do. Many metal | | | | Reverberatory and Puddling are often used |
| casters enjoy making their own furnaces and | | | | interchangeably. By placing the metal in a shallow |
| have done so quite successfully. The plans for | | | | depression and then directing an intense flame |
| home made furnaces are eagerly shared among | | | | over that depression and to the wall, the heat |
| the enthusiasts so finding blueprints and | | | | rebounds to melt the metal. Many casters will |
| instructions should not be difficult. But before you | | | | adjust the length of the flame since a longer path |
| rush off to find the blueprints you may want to | | | | will mean that the heat will be more intense. |
| take time to learn about the types of casting | | | | There are many designs for the reverberatory |
| furnaces available to help determine which one will | | | | furnace, all of which will include exhaust ports and |
| suit your needs. This is not saying that you should | | | | the rear of the furnace must be able to |
| only have one furnace at any given time, but this | | | | withstand the intense heat and be able to bounce |
| way you will know what project will work best | | | | it back into the chamber. |
| for which furnace. | | | | Bronze, aluminum, tin, and many other ores can |
| Cupola | | | | be melted in a reverberatory furnace all |
| Cupola furnaces are among the most popular with | | | | depending on the construction of the actual |
| backyard foundries. Many casters construct their | | | | furnace and the heat of the flame. This type of |
| own cupola which proves to be cost effective | | | | furnace has been around since at least the Middle |
| and highly efficient if done properly. Since cupola | | | | Ages and was used primarily for bronze work. |
| furnaces can achieve high melting temperatures | | | | Electric Arc |
| they are primarily used for the melting of iron and | | | | Electric Arc furnaces are normally used in |
| bronze, though aluminum can also be melted when | | | | Industrial foundries. Most hobby casters do not |
| attention is paid to keeping the temperature low. | | | | use these furnaces due to cost, space issues, and |
| The primary fuel source for cupola furnaces are | | | | a general inconvenience. There are two forms of |
| coke using limestone for flux. | | | | the electric arc furnace, the direct and indirect. |
| By not using a crucible, the Cupola furnace is able | | | | The direct arc has three electrodes which are |
| to melt the metal at a faster rate. While individual | | | | used to heat metal by way of the arc. This |
| designs of these furnaces differ due to varying | | | | creates an incredible amount of heat and so |
| resources and design ideas, the basic component | | | | water jackets and other cooling devices will be |
| of a cupola furnace is the same. The cupola | | | | needed for operation. |
| furnace must be elevated above the ground and | | | | The indirect arc just uses one electrode and |
| installed with a drop bottom usually hinged, which | | | | works in much the same way as the direct arc |
| will allow the excess metal, fuel source, and other | | | | furnace. |
| waste to drop from the furnace. The tap hole | | | | Electric Induction |
| and shaft which will allow the molten metal to | | | | Electric Induction furnaces are becoming all the |
| flow from the furnace and into the ladle and air | | | | more popular with large industrial size foundries |
| shafts are also required. A slag tap hole can be | | | | that enjoy the clean burning and efficiency of an |
| placed on the furnace usually in the back, higher | | | | electrical furnace. Copper coils surround the |
| then the tap hole, which will allow the slag to flow | | | | crucible with the metal inside which can reach |
| out easily. | | | | extremely high temperature suitable for melting |
| With most small home foundries, the cupola | | | | most metals. |
| furnaces are preferred over that of other | | | | Rotary |
| furnaces for its high melting rates and for how | | | | The Rotary style furnaces are hailed for their |
| easily the construction of such a furnace can be. | | | | ease of use being fully or at the very least |
| Reverberatory | | | | partially automatic. These furnaces tend to be |
| The Reverberatory Furnaces are commonly | | | | harder to construct though there are resources |
| found in industrial plants but there have been quite | | | | and companies online that sell rotary furnace. |
| a number of home grown foundries that have | | | | The different furnace types do affect the quality |
| used this furnace type with much success. The | | | | of the work being produced, so it is important to |
| basic idea of a Reverbeatory Furnace is to use | | | | keep that in mind as you cast. With a little trial |
| the heat reflecting off a surface, usually brick, to | | | | and error, you should find the perfect furnace to |
| heat the metal, which is aluminum in most cases. | | | | fit your needs so you can start building one of |
| This way, the metal does not come into contact | | | | your very own. |