Forging aluminum used to be a problem for even experienced blacksmiths. Forge welding aluminum was not even considered. Following these steps in a Forgemaster TM forging furnace will enable even novice blacksmiths to be quite proficient at forging aluminum.
1) Reduce the heat in the forge by lowering the regulator pressure to 6-7 psi. If your Forgemaster TM forge is equipped with a door, work with the door open. These two actions will lower the temperature inside the forge. Most aluminum and aluminum alloys used for hand forging becomes malleable at 700-900 degrees Fahrenheit, and melts at about 1400.
2) It will not take long for aluminum to reach forging heat. Several methods can be employed to determine the proper heat:
a. mark the aluminum with an 800 degree "temple stick" and watch for the mark to melt.
b. remove the aluminum from the forge and drag it across the face of your anvil. If it is at forging temperature it will seem tacky and resist dragging.
c. remove the aluminum from the forge and touch it to a piece of wood or newspaper. If it lightly scorches either of these it is ready to work.
3) As soon as the piece reaches the desired forging temperature you may begin to work. The aluminum will probably not need to be reheated, as it will remain in a soft state. Should you feel the need to reheat the piece be careful, a few seconds too long in the fire will result in an unusable piece of aluminum.
4) If the aluminum breaks and crumbles when you strike it with your hammer it indicates that it was overheated.
Forge Welding Aluminum
The technique used to forge weld aluminum is considerably different than steel or iron welding. The forge temperature should be kept at a low, soft heat (5-7 psi.). Use a flux core aluminum rod for this procedure. 1/8" diameter Cor-Al aluminum welding rod manufactured by Welco is excellent. The following series of photographic steps will guide you through the process of forge welding an aluminum barshoe.
1) Heat the shoe (as described in the section above) to a forging heat.
2) Turn the heels as you normally do to forge a steel bar shoe. These photos shows how to forge a crisp corner on the barshoe after you turn the heel.
|Side and Front View|
3) After turning and forging each heel of the shoe, scarf the ends as you would for any forge weld. The overlap does not need to be as thick as for a steel bar shoe since most of the forging of an aluminum barshoe takes place before the weld is made.
4) Photos #3 & #4 show the correct taper and overlap of the scarf area to will be welded.
|End and Top View|
5) Now for the delicate part of the process. Photos #5 & #6 show the farrier melting a small piece of the Cor-Al welding rod onto the area of the scarf. This piece will serve as a reference point for determining when the area is hot enough to weld.
6) Watch the small piece of aluminum welding rod carefully. It will become bright and then begin to flow. As soon as it melts begin applying the welding rod, so that the entire weld area is liquid looking. Pull the shoe out of the fire as you apply the rod. When the rod stops flowing into the weld area you may return the shoe to the fire if you feel the need to add more filler rod. Be careful of too much heat. The reference is the Cor-Al rod (when it becomes liquid and flowing, remove the shoe from the fire. When it becomes solid and no longer liquid you may wish to apply a little more heat.)
7) After you have enough filler rod and the aluminum is welded, allow the material to cool. If you are making a pair of bar shoes, place the first shoe to the side while you weld the second. Here is what the weld should look like just after you finish welding.
Not a very pretty sight. However, after it cools down, brush the blackened area of the weld with a wire brush. You may then forge the weld without fear of separation. This will allow you to fashion the bar to suit your requirements. You will not need to heat the shoe again in order to forge it. Aluminum will remain malleable even after a long period of time.
The finished product will be similar to this: