Brass has a relatively low melting point compared to iron, steel, or gold, but smelting brass still requires a special furnace. Many metalworking hobbyists start with aluminum, a material that melts more easily, but brass is often the next step. Make sure you follow all safety precautions and above all, keep pets and children away from your work area.
Step
Part 1 of 3: Setting Up the Furnace
Step 1. Look for suggestions specific to your goal
While this article provides good general instructions for smelting brass, there are many factors to consider when setting up a kiln. Seek advice online or through foundries to find a furnace setting that fits your budget, the volume of metal you wish to smelt, and any type of metal you may wish to use.
One of the most popular metal processing forums on the internet is IForgeIron. The hobbyists and professionals on the forum can advise you
Step 2. Prepare the metal smelting furnace
Smelting brass requires a lot of preparation and a special furnace that can heat the brass quickly before too much of the metallic components are oxidized. Purchase a metal smelting furnace that can heat up to 1,100ºC, which is made of refractory and heat-resistant materials. Most brass will melt at 900ºC, but a higher maximum temperature will reduce the chance of error and make the brass easier to pour.
- Choose a furnace large enough to hold the crucible and brass you wish to smelt.
- Consider the fuel you will use. Waste oil is a free source of fuel, but you may need a more expensive furnace. Propane furnaces are cleaner, but require you to buy more fuel. Solid-fuel stoves are the cheapest option or build your own, but homemade stoves require significant fuel costs and require frequent cleaning.
Step 3. Separate your brass from other materials to be smelted
You may already have brass ready to be melted down, but if you want more raw materials, thrift stores and/or bazaars often stock the treasure. If that doesn't work, you can try calling a local junk center. Separate brass from other materials, especially non-metallic materials such as glass, plastic, paper, and cloth.
Step 4. Clean the brass
Wash brass with soapy water to remove surface contamination such as oil and excess oxidation before smelting. If the brass is varnished, blot the varnish with acetone, varnish thinner, or paint remover.
Always wear gloves and work in a ventilated area when removing varnish, especially if using paint remover
Step 5. Prepare a saucer
The crucible can hold the molten metal while it is in the furnace. For brass alloys, graphite crucibles can be the best choice because of their durability and ability to heat up quickly. You can use crucibles made of other materials, but make sure they can withstand the high temperatures required.
- Before using the graphite crucible, heat the crucible to 95ºC for 20 minutes and allow it to cool. This step can remove excess moisture that could cause a steam explosion.
- Each cup can only be used for one mixture. If you are also planning to melt aluminum, iron, or other metals, then you will need a cup for each of these metals.
Step 6. Collect all the tools
You will need tongs, a caster, and a caster rod to handle the metal. Steel tongs are used as cup handles and for inserting and removing the crucible from the furnace. Steel scoops are used to remove debris from metal surfaces prior to pouring. Lastly, the pouring handle is used to hold the cup firmly and so that you can tilt the cup to pour the brass.
- If you can weld, you can build your own tool from scratch.
- Optionally, purchase a pyrometer to measure high temperatures, so you can more easily determine when the brass is ready to be poured.
Step 7. Place the furnace in a well-ventilated area
Open space is almost a must for smelting brass, as toxic fumes are almost impossible to escape. An open garage or similar room structure is a good choice.
Even when you are melting other metals, make sure your furnace is ventilated enough. Furnaces require a lot of air because they produce carbon dioxide and other gases, depending on the fuel source
Step 8. Add a dry sandbox
Even dry materials, especially concrete, can contain moisture. If a drop of molten metal comes into contact with moist air, the liquid will turn into a vapor and expand rapidly, causing the molten metal to splatter. To avoid this, place a dry litter box near the furnace, and always carry and pour molten metal over the sandbox.
Step 9. Assemble the metal mold
The easiest way to handle molten brass is to pour it into a metal mold. Forming brass into more complex shapes requires much more preparation. Look for information on cast sand or foam inclusion castings if you are interested in casting machine parts or artwork. If possible, seek supervision from an expert when carrying out this process, as for beginners, the success rate is usually low.
Part 2 of 3: Follow Safe Practices
Step 1. Put on heat-protective gloves, an apron, and boots
Be aware that the hobby of smelting metal in the backyard may lead to the occasional accident. It's not a big deal, as long as you don't forget to wear protection. Leather gloves, leather shoes, and a heat-resistant apron can protect you from even the smallest of incidents. This protective device is often a protection when welding.
Step 2. Wear wool or cotton clothes
Wear long-sleeved shirts and long pants under your visor, so that drops of molten metal don't land on your bare skin. Cotton and wool tend to put out heat quickly. Avoid synthetic materials, which can burn for a long time or melt on your skin.
Step 3. Protect your face and eyes
Wear a protective mask to protect your face from drops of molten metal, whenever you handle hot metal. Put on a welding mask or sunglasses before heating the metal to 1,300ºC or above, to protect your eyes from excessive UV rays.
Step 4. Consider using a respirator
Brass is an alloy of copper and zinc, sometimes it is also mixed with other metals. Zinc has a relatively low boiling point (907ºC), which is often reached before the brass is completely melted. This causes the zinc to burn, producing white smoke that can cause temporary flu-like symptoms when inhaled. Other materials such as lead, which may also be present in brass, can cause long-term damage with repeated exposure. Respirators for metallic acids (P100 particulates) can protect you from these hazards.
Children are at a higher risk of lead poisoning than adults, and they should be kept away from stoves when in use
Step 5. Remove items from the area
All combustible and wet materials must be removed from the area, as they may cause fire and vapor explosion when molten metal droplets touch them. Keep your workspace clear of all tools and unimportant objects, to open a clear path between the furnace and the mould.
Step 6. Find out the nearest water source
Don't bring any damp items close to the stove, but you should have cold water prepared, running water in the same area, or at least a large bucket of cold water. If you get burned, immediately flush the affected area with water without stopping to allow your clothes to come off.
Part 3 of 3: Melting brass
Step 1. Heat the mold and pour
Heat the metal mold to above 100ºC to dry the moisture, or the molten metal will scatter as it is poured. Remove the mold from the heat and place it in dry sand. It is also recommended that you preheat the drain for the same reason.
Step 2. Place the saucer on the stove
Position the saucer into your furnace. In solid-fired stoves, charcoal is often placed around the saucer, but follow the instructions for the stove model or home stove type.
Step 3. Turn on the furnace
Follow the instructions on your stove, or take the advice of an experienced hobbyist if you are building a stove in your own backyard. Usually, you'll need to add solid fuel or ignite the gas, and then start the stove with a torch.
Step 4. Fill your cup with brass
After 10-30 minutes, add the brass pieces to your saucer, handling it gently to avoid damaging the cup. Waiting until it's partially heated can help heat the brass quickly, giving the zinc mixture less time to separate and burn.
Step 5. Keep burning the furnace until the brass is completely melted
The amount of time required will vary greatly depending on the power of the furnace. If you have a pyrometer to measure high temperatures, keep in mind that most brass will completely melt at about 930ºC, but this temperature can vary by around 27ºC depending on the type of brass. If you don't have a pyrometer, continue to the next step after the metal has turned orange to yellowish orange, or when the color becomes barely visible in daylight.
- Remember to avoid the smoke rising from the stove, and wear safety equipment when you are near it.
- While heating the metal slightly above its melting point makes the metal easier to cast, overheating can cause problems, such as oxidation. Assessing when the metal is ready to be cast will become easier with more experience.
Step 6. Remove metallic impurities from the brass
Use your steel scraper to remove any discolored topcoat or oxidizing debris from the brass, and dispose of this waste in dry sand. This will also allow you to assess whether the brass is completely melted, but try not to stir the brass or plunge the spoon too deep into the metal. Too much stirring can mix air and gases into the metal, and can cause defects.
Note that some other metals, such as aluminum, will produce gas, and must be stirred to allow the gas to escape
Step 7. Pour the molten brass into the mould
Remove the cup from the furnace with steel tongs, and attach it to the pouring rod ring. Use a pouring rod and tongs to lift the cup and carefully pour it into the mould. You'll likely spill a bit of metal, and that's why the mold should be placed on dry sand to minimize splashing. Now you can fill the cup with more brass, or turn off the stove and wait for everything to cool.
The furnace takes a long time to cool, but before that, the mold should be ready
Tips
- Practice burning a little brass until you can safely reach the melting point before you try larger projects.
- You can build your own stove in your backyard. Seek expert advice before trying this.
- Have a fire extinguisher nearby for emergencies.
