How to Weld Brass: Methodologies and Tips
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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.
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.
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.
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.
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.
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.
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.
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.
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