How to Weld Brass: Methodologies and Tips
Last Updated on
Brass is an alloy of zinc and copper. Modern brass contains around 67% copper and 33% zinc.1 About 2% of lead is added to the alloy to enhance its machinability. The alloy is desirable because of its corrosion resistance, hardness, and machinability, electrical and thermal conductivity.
The alloy is used in low friction applications such as locks, hinges, electrical plugs, sockets, and decorative items. Welding brass is possible but a bit challenging because the zinc content greatly affects the melting point.
Before you weld, you must find the zinc content of the brass you are welding. This is necessary since zinc has a lower melting point than copper; thus, overheating brass can cause cracking or result in a porous weld. You should select the correct shielding gas since brass can crack or develop porosity as the alloys separate.
This article offers a comprehensive guide on welding brass using TIG, MIG, and flame welding methods. You will also learn the safety precautions to apply during the welding process.
The 5 Steps for Brass Welding Preparation
Just as when welding any other metal or alloy, it’s important to know the steps to follow to create strong and durable welds.
1. Cut Brass Pieces
The first thing you need to do is to cut the brass pieces you will be working with, including brass rods. You can cut using a hacksaw or pliers. You have brass tubing, which you cut using a tubing cutter or a saw. Besides, you have the brass sheets; you can cut using shears or a hacksaw.
https://www.instagram.com/p/CdG621KvaFB/
2. Bending the Brass
After cutting the brass, you need to bend it to weld properly. You can apply different approaches to bend the brass tubing, rod, and sheets. Using a pair of pliers, bend the brass wire by placing it in the pliers, holding them in one hand, and manipulating the other part of your wire with the other hand.
To create a sharp curve, use round-nosed pliers and begin by bending the wire into the jaws. For extremely sharp ends, use a pair of pliers in each hand.
With a heavy brass rod, you need to use a bending jig to save time by mounting the jig to a bench and then clamping it down. When using a jig, you should put the rod into the slots. Then, use your hands to bend the rod as you manipulate it into the jig area.
Bending brass tubing can be challenging because it can kink up and crush fast. Use a spring bender that fits over the tubing you want to bend. Move the bender into the tubing and the center of the part you want to bend. Use both hands to bend the tubing, pressing your thumbs hard into the bend.
The other important thing is to bend your brass sheet by placing it between two pieces of plywood and holding them down using a vise. Get another piece of wood, and apply it to exert pressure on the brass to create a bend without messing up your metal.
Now that you understand how to prepare the brass pieces by cutting and bending them, let’s look at the process of MIG, TIG, and flame welding the brass pieces.
3. Get Your Working Area Ready
The first thing to do is make your work area ready. Make sure you take all safety precautions by removing anything flammable from the workspace. Ensure your area is well ventilated or have some fans to blow out the fumes.
https://www.instagram.com/p/Ck5QuUZj7nx/
4. Clean Your Pieces of Metal
The next step is ensuring that your brass pieces are clean and ready for welding. You can clean the brass areas using scotch Brite pads, sandpaper, or a file. You should have a fiberglass scratch brush around to help scrub some of the hard to clean areas.
Note that some brass pieces can have a lacquer coat to maintain brightness. When welding the brass pieces, you should remove the lacquer to weld the pieces effectively.
After scouring the brass pieces, wipe them off with alcohol. Alcohol removes all the debris, particles, or oil left on the brass. After you finish, remove the alcohol from your working area because it is flammable. Allow the pieces to dry.
5. Get the Brass Pieces Into the Right Position
Get clamps to hold your pieces together. You can opt for the Tall T-pins or other heavier metallic objects. Regardless of your clamp, ensure your brass pieces are in the right position. Besides, remember that your pieces will get very hot, so don’t place anything near the joint section you are welding.
https://www.instagram.com/p/CRvXQJDF8hO/
Methodologies for Welding Brass
1. MIG Welding
You can get high-quality welds when using the Metal Inert Gas welding method. However, make sure that you use the correct filler wire. If you use the wrong filler metal, you end up with a low standard and discolored weld.
Copper and zinc are the major components of brass. The correct filler wire for MIG welding is CuAI8. The wire contains copper and 8% aluminum. You can also use any other filler metal with significant zinc content. This is necessary because the zinc burns out with high arc temperatures, messing up the entire process.
Since you have already set up the brass pieces in the right position, you can now start MIG welding your brass pieces following the steps below.
- Get on all the required protective gear to prevent injuries. You should have a helmet, boots, insulated gloves, masks, and a full-sleeved shirt.
- Use a shielding gas containing carbon dioxide and argon or pure argon. For high-quality brass welds, use a 75/25 mixture of Argon and CO2. If you don’t use enough shielding gas, zinc vaporizes, producing zinc oxide when heated. This gas escapes as toxic fumes that are not good for the welder. To minimize zinc oxide production, you should keep the weld section short. Do this by going for the stitch welding technique other than the one continuous joint. By doing this, the molten puddle has enough time to cool off by ensuring that the material doesn’t get exposed to constant heat for long.
- Use the correct filler metal for brass welding. Use CuAI8 or any other with a good amount of zinc.
- Now thread your welding wire with your welder reel and take it out with the torch tip. Have the welding wire extended about ¼ inches out of the torch. After setting the wire, activate your welding gas and start the welding process.
- Start welding from any joint end, holding your torch at 30 degrees above the joint edge. Ensure the torch is sharp to hit the brass pieces on the flame tip. Stop when the heat becomes excess and wait until you can control the beads.
- Fill the joint by moving your torch slowly, ensuring it is at a fixed angle.
- Let the casting cool and avoid shaking the brass before it cools to ensure the joint doesn’t open.
https://www.instagram.com/p/CRt5fuBsk37/
2. TIG Welding
Brass features high levels of thermal conductivity, and the zinc in the alloy has low melting points. During TIG welding, the molten zinc can boil and jump over the electrode, halting the entire process. To TIG weld brass effectively, you need to use an AC power inverter with thirty-second pulses every second.
During the brass TIG welding process, apply minimal heat to keep the weld puddle going. Take the heat off the material after a few seconds to check the pool. This ensures that you don’t overheat the base metal.
When TIG welding brass, use CuSn6 welding rods to get great results in color coordination.
- Put the sharp tungsten rod into your torch. Make sure you put it in the middle of the metal cylinder. Let the welding rod move out from the tip of the torch by a quarter inch.
- Turn DC on your welding machine and ensure you get the correct settings depending on your TIG welder.
- With the right setting, turn the torch on, holding its tip one inch above your brass joint. Start welding from any end, holding the torch at a 75-degree angle. Hold the torch and fill the joint until the brass melts.
- After you are done, give your joint time to cool, and don’t move the joint until it is strong. Protect the heated area under argon to allow it to cool off completely. Exposing the heated brass to the atmosphere can lead to porosity, damaging the weld.
https://www.instagram.com/p/CKQZXq5ssJd/
3. Flame Welding
Flame welding is another method you can use to weld brass. For perfect results in color match and strength, you should use a CuZn39Sn filler wire. When using this method, you should closely check the effect of flame in the material to know the amount of excess oxygen required for the welding.
There are three flames associated with flame welding. If you don’t want any chemical effect on your working space, you should use a neutral flame. You can use carburizing flame, but it doesn’t work well for metals that absorb carbon.
Oxidizing flame is the best to use since it carries more heat than neutral and carburizing flames. It’s the most perfect to use on zinc and copper, making it suitable for brass flame welding.
- Open the oxygen valves and the acetylene gas cylinders using cylinder keys. Ensure you open it gradually since doing it at once will damage the regulators or cause an accident. Open the cylinder valve spindles with a single turn only.
- Now open the control valve for the fuel gas in the blowpipe. Then, adjust the regulator until you attain the proper working pressure. This ensures that the hoses’ air is purged before starting the welding process.
- Light the gas with the correct spark lighter, holding it at the correct angles to the nozzle. Avoid using liquid igniters since they are very dangerous.
- Adjust the supply of acetylene gas to the blowpipe until the flame stops smoking. Once the flame stops smoking, boost the oxygen supply slowly by slowly using the control valve. The final flame should feature a white-colored cone with less acetylene haze. This shows that the blowpipe is adjusted effectively and ready for flame welding.
- Now apply your flame to your brass weld. Adjust the flame and move the torch carefully over the welding area at an even pace to get high-quality results. Holding the flame very close to your welding material for long creates holes in the welding material. On the other hand, if you don’t make enough flame application, the piece will not melt.
- Move the torch in short runs to be sure of high-quality results. Focus on the torch angle and amount of flame and adjust correctly.
- After flame welding, allow the brass weld to cool down to get strong joints.
Safety Precautions and Tips When Welding Brass
- Wear protective boots and gloves to protect against burns since zinc usually splatters. You also need a fume extractor to protect against toxic gasses produced during brass welding.
- If you use MIG or TIG brass welding, ensure you have good ventilation and an auto-darkening feature. This is necessary because the two welding methods use bright arcs that can damage your eyesight.
- Choose a shielding gas that offers enough coverage, thus protecting the entire metal. Avoid turning off the gas supply until your weld has cooled off. This ensures your weld is not contaminated, leading to cracking.
- Remove all fire hazards from your welding area.
- Handle the cylinders carefully and make use of the correct type of gas.
- Only use a hose that is in perfect condition and use the suitable gas for a specific gas.
- Never light torches using matches, cigarette lighters, or pilot lights.
Final Thoughts
Using TIG, MIG, and flame welding methods, you can get high-quality brass welds. However, before you start, you need to determine the percentage of zinc in the brass material. This is necessary since zinc has a lower melting point than copper. You should also avoid overheating brass as you weld to avoid cracks and porous welds. Besides, choose the right protective gas since brass tends to crack or develop porosity when the alloys separate.
To get the right results, prepare your brass pieces by cleaning them with sandpaper or any other recommended cleaner. This makes them ready to weld and form strong joints. Use TIG, MIG, or flame welding methods according to the welding materials you have or the one you are more comfortable using. After the welding, allow your pieces to cool for stronger joints.
Take the proper precaution by wearing protective gear and ensuring that the welding area is safe from all fire hazards.
Featured Image Credit: Photology1971, Shutterstock
