Aluminum is one of the most used metals in the modern manufacturing industry; its resistance and malleability make it the ideal material for different purposes. For all these reasons, it is perfect for DIY forging projects. With the right information and the right materials, casting aluminum can turn into a hobby and an extra source of income.
Steps
Part 1 of 3: Melting Aluminum in a Small Forge
Step 1. Prepare the forge
Place it on a metal easel or an insulated surface. Check that the base can withstand a temperature above 660 ° C, which is necessary to melt aluminum. Do not use any wooden or plastic surface, as it will melt or burn easily. For best results, place the forge on a sturdy metal stand that is very stable.
Step 2. Place the crucible in the forge
Make sure the crucible is in the center of the forge. A steel crucible is the best solution for melting aluminum.
If you are using a coal forge (instead of a gas one), create a layer of coal at the bottom of the forge and place the crucible on top of it; then fill the space between the insulating material and the crucible with more charcoal. By placing a layer of charcoal under the bowl, you allow it to heat up faster and more evenly
Step 3. Connect the torch
If you are using a propane gas fired forge, connect the end of the included torch to the side opening of the forge. Follow the instructions provided with the forge (coal fired ones can be a safer DIY project, in some ways).
- Insert the blower tube into the air supply opening. After filling the forge with coal and inserting the crucible, you need to prepare the bellows. Insert the steel end of the pipe into the forge. You can use the bellows to blow into the plastic end and keep the air flowing, or connect an electric hair dryer that provides more constant ventilation.
- Since the bellows are in a corner, put something under it to keep the pipe raised (for example one or more bricks); this foresight prevents the forge from breaking or being damaged.
Step 4. Light the forge
Once the bellows and crucible have been placed, set the coals on fire. The simplest way to proceed is to use a propane torch that quickly heats the coal. While applying the fire, put air through the bellows tube or turn on the hair dryer to the minimum; in this way, you feed the flame and increase the heat. Place the lid on the forge and let it warm up.
- Wait for it to warm up for about ten minutes before putting the aluminum in it.
- The temperature must reach a value above 660 ° C.
- Once the crucible becomes red-hot, the forge is hot enough to melt the aluminum.
Step 5. Put the metal into the crucible
When the temperature reaches the proper level, you can start melting the aluminum. You have two alternatives: you can remove the lid and put the cans intact in the crucible or leave the lid in place and insert the crushed cans through the vent. Both methods are fine, but if you leave the lid on the forge, some of the metal will oxidize. The cans melt within seconds, so you need to quickly add more.
- It is important to act quickly to create a "puddle" of molten metal. This is a crucial step in preventing the cans from overheating and turning into gas, a process known as oxidation.
- You can put aluminum in the crucible while wearing heat-resistant gloves, but using long metal tongs is also safer.
Step 6. Remove the crucible from the forge
Use a pair of long foundry pliers and slowly remove the container. To avoid oxidation, remove the molten aluminum at least three minutes after the last piece has melted.
Step 7. Separate the pure aluminum from the slag
When you have melted enough metal to fill the crucible, you need to get rid of the impurities. Objects such as cans contain several other materials (plastics and various metals), which create slag or scraps. These particles form a dense, lumpy layer on top of the pure molten aluminum; the easiest way to get rid of them is to slowly pour the liquid metal into a steel mold and then tap the slag away from the crucible.
By keeping the crucible clean, you can quickly melt larger amounts of metal
Step 8. Pour the molten aluminum into metal molds
At this point, you can allow the aluminum ingots to cool in the air and then take them out of the mold, or you can use water to speed up the cooling process. The simplest technique is to grab the piece with pliers and transfer it into water for about ten seconds. After this "bath", the ingot should be cool enough to touch; however, you should continue to handle it with pliers, to avoid burns.
Pure aluminum ingots can be reused for other projects and their subsequent smelting will not produce as much slag as the previous one
Step 9. Empty the forge once it has cooled completely
Once you have finished melting the aluminum, turn off the blower torch and or tube (according to the instructions provided) and allow the forge to cool in the air for several hours. Once completely cooled, disconnect and disassemble all components and collect ash and other coal residues from inside the forge.
Keep an eye on the cooling process, especially in the beginning, when the forge is hot enough to ignite wood, paper and textiles
Part 2 of 3: Making an Artisan Aluminum Forge
Step 1. Build the external structure
Buy a 10-liter steel bucket with a diameter of 30 cm. This is the classic bucket you can buy at a home or gardening store.
It is important that the bucket is made of steel, since it works with very high temperatures; other materials melt or can become brittle when subjected to the intense heat generated by the forge
Step 2. Mix the materials for the interior lining
Mix 4 kg of chalk with the same amount of kinetic sand and 3.5 liters of water in a 5-liter or larger bucket. Quickly work the ingredients with your hands; it is important to moisten all the powders and remove any lumps. After a few minutes, the mixture should be quite liquid and uniform in color.
Since the mixture dries in about 15 minutes, you need to proceed to the next step fairly quickly
Step 3. Pour the insulation material into the bucket
Once you have eliminated any lumps from the mixture, slowly pour it into the steel bucket; it should fill the container completely, leaving about 8 cm of free space from the top edge.
To avoid dirtying your surroundings, pour the mixture slowly to limit splashing
Step 4. Model the central part of the forge
Fill a 2.5-gallon bucket with water or sand and place it in the center of the insulation compound. Slowly push it into the material, then lift and lower it a few times to level the insulation before it settles. Finally, hold the small bucket still for two to three minutes and let the surrounding material dry.
- When the kinetic sand and gypsum compound has hardened, the small bucket should not move when you remove your hands.
- Let the insulation settle for an hour and harden.
- Clean up any splashes that have fallen on the top edge of the steel bucket.
Step 5. Remove the inner bucket
When the insulation has hardened, take pliers or parrot pliers to remove the plastic bucket you used to create the hole; grab it with the tool and turn it on itself. By applying enough force, you should be able to pull it out of the cast.
Step 6. Drill a hole to create the vent
To facilitate the flow of air into the forge, you need to open a hole in which to insert the bellows. Use a hole saw with a diameter of 28.5mm connected to a power drill and drill a hole in the top of the bucket (7-8cm from the lid). When you have cut the bucket, tilt the tool about 30 ° and continue drilling. This hole should be the perfect size to insert a 25mm tube, which acts as an air intake.
- You can buy the hole saw at the hardware store. Check that it is a suitable blade for cutting metal.
- Creating an inclined air vent prevents molten metal from escaping from the forge should the crucible break.
Step 7. Make the blower
Take a 25mm section steel pipe, 30cm long and screw one end into a 25mm PVC fitting. At this point, insert a 60 cm long PVC tube with a diameter of 25 mm into the smooth end of the attachment; the latter should be equipped with a threaded part for the steel pipe and a smooth part for the PVC one.
The blower tube should fit into the air intake, but it should not get stuck to the point where it is difficult to put it in and out
Step 8. Make a lid
Fill a 5 liter bucket with 2 kg of chalk, 2 kg of sand and 1.7 liters of water. Insert two 10 cm "U" bolts vertically into the plaster, with the ends of the nuts facing down; wait for the mixture to harden for an hour. Once stabilized, you can simply take the "lid" out of the bucket. Finally, drill a hole in the top, using a power drill and a 75mm hole saw.
- The air intake reduces the pressure inside the forge and allows you to add metal pieces without removing the lid.
- Try to make a hole with the same diameter as the crucible; in this way, you avoid heat loss when you melt the aluminum.
Part 3 of 3: Preparing to Melt Aluminum
Step 1. Find suitable aluminum pieces
The best sources for scrap items made from this material are parts of old cars. Engine heads, transmission housings, water pump housing, and pistons are all perfect examples. The most common sources are items such as beer and soft drink cans, furniture frames, house side panels, window frames and disposable oven trays. However, these objects are generally made up of weak alloys, which contain a lot of impurities, create a lot of slag and oxidize quickly.
An easy way to melt aluminum cans and prevent oxidation is to add them to a certain amount of already molten metal
Step 2. Put on your personal protective equipment
When working in extremely high temperatures, it is important to use adequate protection. To handle molten metal, you should wear a thick shirt, heavy pants, an apron, face shield or goggles and leather gloves. These devices prevent liquid metal from burning the skin; Additionally, since molten metals emit harmful gases, you should also wear a mask.
Step 3. Find an outdoor spot or a well-ventilated room
When you work with molten aluminum, some alloys release toxic vapors; for this reason, it is important to proceed in a well-ventilated space or outdoors. This precaution also allows you to stay cool enough, while working with materials at very high temperatures, avoiding dehydration and heat stroke.
If you start to feel bad, have a headache or feel dizzy, turn off the forge and take a break; go to a cool place and drink some water
Step 4. Use the right tools
Before you start melting aluminum, make sure you have all the proper tools to handle the liquid metal. You need a pair of metal tongs, a filter or stirring rod, a crucible and the forge. Items such as the crucible and forge can be made at home or purchased online or in specialty stores.
Step 5. Always think about your own safety
Since a relatively low temperature is enough to melt aluminum, it is possible to do so with several unsafe methods, other than the forge. Avoid melting it inside large bonfires or on the barbecue; these are far less controllable techniques, which can start a fire or cause injury.
