Welders prefer TIG welding to get attractive beads with a consistent and smooth texture. The biggest problem here is the absence of any cleaning agent or flux. That means the metal to be TIG welded needs to be flawless before welding. Unlike other welding methods, you have to clean it first. But, how to clean and prepare metal for TIG welding?
You have to grind or sand metal to TIG weld it. Then you will use a cleaning agent to get rid of chemicals. Remember that only shiny and clean metals will take strong beads from TIG. Oily, rusted, contaminated, greasy, painted, or rusty metals will not be workable.
All the necessary and relevant information is in the following sections of the article. I hope you’ll find them helpful.
Why Do I Need To Clean And Prepare Metal For TIG Welding?
Before I discuss the cleaning methods, I should explain why TIG requires it in the first place. While welding, you melt the metal edge with its filler rod. When melted, the metals flow and become fused permanently.
So, if they are rusted or dirty, the filler sticks to the rusts instead of the joint. Consequently, when the joint or bead gets pressured, the rust starts pulling off to break the weld.
Other welding methods involve flux with the metal’s filler rod. After reacting with the surface contaminants, it removes them. Since TIG has no flux, you must clean the metals by yourself. You have to follow two steps before welding: mechanical cleaning, followed by chemical cleaning.
How To Clean And Prepare Metal For TIG Welding
Part 1: Mechanical Cleaning
In the first step, you have to clean the contaminants physically from the metal surface. You can use bench grinders, sanders, angle grinders, and wire brushes to do that. Each works differently, varying within the surface shape, size, and condition. Let’s look at all of them.
Many bench grinders have a pair of wheels, fine and coarse. Their grinding wheels are similar to that of angle grinders without cutoff wheels.
They give the best results when used for tiny parts that you can handhold. It is not that effective to get heavy and gigantic pieces aligned with them to clean without causing any joint damage.
You can use sandpaper for tiny pieces. It works better than wire brushes, helping you get bright metals sooner. Like wire brushes, it is unlikely to damage metals. The reason is the user will stop the moment they get the desired brightness.
Sandpaper is not the best choice for working on big pieces because that would take forever.
Disc And Belt Sanders
Sanders are not as aggressive as grinders, but they are swift at cleaning. Since they are wider, they make a perfect option for clearing large joints. It lets you cover large areas without making rough places or gouges.
If the metal is thin and dirty, your solution is wire brushes because they ace at knocking off huge dirt chunks and grime. In the cases of road construction or farm equipment, there may be grease and dirt stuck to metals. Wire brushes will get them off in the fastest of time.
Get some brush and begin scrubbing if you want to clean metal. You should get the crusty or loose stuff from the joint shortly. The downside of it is speed. It does not work as fast as others. Plus, deep cleaning is difficult with this tool.
Angle grinders spin their tiny abrasive wheel, which runs pretty fast. They are handheld and small. Using internal gears while spinning their wheel, they set it at right angles toward the motor.
They are pro at cleaning chunky metal pieces. If they are too large to hold, you can keep the grinder in one hand to get your way around the joint. However, their performance is not remarkable for small parts. In that case, you should use a vice to keep the part before grinding.
With those mechanical cleaning tools, the actual process is simple. Keep grinding along the joint till the rust vanishes and your metal shines. Whatever equipment you use, just don’t stop it until you see it shine. Nevertheless, stay careful not to make holes or damage the joints.
Maintaining Safety Measures
Below are the basic safety measures you must maintain while welding.
- Safety Glasses or Goggles: Even sandpiper and wire brushes can throw metal particles that might go into your eyes, scratching your eyeballs. You will not need welding goggles. Clear lenses or shop glasses will do the trick.
- Gloves: Scratches from busted knuckles and scrapes will occur if you work barehanded with metals. Grab a pair of gloves to prevent it. Plain leather is the best option for ensuring both sensitivity and protection.
- Long Sleeves And Pants: If it is a sander or power grinder, get long pants and sleeves to shield your body from sparks.
- Earmuffs: Sanders and grinders are loud. Damage caused by loud sound adds up at one point. So, make it a habit to wear earplugs or earmuffs while getting prepared for welding.
- No baggy clothing: Do not wear dangly or long clothes while working with sanders or grinders. Getting your sleeves caught in rapidly spinning grinders will make you go to the emergency rooms.
- No Synthetics: Sparks from grinders can melt the plastic. Never wear synthetics during welding. Choose a heavy, cotton-made outfit.
Part 2: Chemical Cleaning
After removing the dirt and rust, proceed with chemical cleaning. There you have to get rid of any paint, oil, grease, and other chemicals in the joints. These chemicals can pore into the metals when ground. You have to use a different chemical to deal with this. Afterward, you will make sure there is no trace of your cleaning solution.
Acetone removes chemicals from the surface and evaporates to give you a squeaky clean joint. But there are safety issues. Acetone is highly flammable and results in harmful fumes after vaporizing. You should use fume hoods or select a well-ventilated environment to apply it.
While you are at it, ensure that it has evaporated wholly. Also, remember to store the acetone bottle safely before welding.
2. Paint Thinner
It is less extreme than acetone. It works as a degreaser and can remove paint. Its fumes will be nasty. So there should be good airflow prior to using it. Its flammability is not as high as that of acetone. However, you have to stow it safely before welding.
3. Denatured Alcohol
This is also a decent degreaser and a somewhat fair paint remover. The flammability is lower than that of the other two.
But its alcohol is flammable, meaning it will require you to use it amidst proper ventilation and keep the liquor locked before proceeding with your work.
The term ‘denatured’ here refers to the mixture of alcohol with different chemicals. They limit the use to industrial purposes and turn it undrinkable.
4. Citrus Degreaser
If you can confirm that the metal has no paint, you should consider this option. The manufacturer made the degreaser with water and orange oil. So it is safer than alcohol or acetone.
Since it is water-based, it will not burn. Another plus point is that it smells like oranges, not chemicals. If you apply the degreaser, use some water to clean it off before welding.
5. Commercial Cleaners
You will find some chemical mixtures in the market to clean and prepare metal for TIG welding. They are metal-specific, indicating they work on specific metals. So, if you decide to buy them, learn the metal type you will weld before purchasing cleaning fluids.
Most commercial cleaners need neutralizing agents after application. Buy the right one and follow its manufacturer’s directions. Learn the disposal process as well. Throwing it in a drain might cause you serious troubles.
Step 1: Joint Preparation
When your metals are clean, start preparing the joint. If they are 3/16 inches or less, much preparation will not be necessary. If they are thicker, you have to bevel the joint edges. Beveling refers to grinding an edge corner to connect the pieces like a V instead of parallel lines.
Beveling enables the weld heat to go deep into the metals. If you weld only along the joint edge, the bead becomes tall. Thus, the heat will not penetrate properly. If that happens, the metals will not fuse. Hence, the welds will become weak.
Filling the bevel will take several passes in the case of thick metals. This is the root and cap technique. The root is your first bead. The others to go over it are caps. This system allows the joint to fuse entirely and generate the best weld.
Step 2: Bevel Preparation
You will make bevels with grinders. You can take the grinder you bought to clean your joint to bevel. Any coarse or medium grinder will do.
Coarse works faster, but medium offers better protection. It is difficult making mistakes and getting deep gouges with medium wheels.
Engineered projects need their bevels to be precise, which should not be necessary for your home projects. A bevel of 45 degrees will be more than okay. It is halfway between horizontal and vertical.
Your bevel does not have to be that deep. Calculate how much dept the welder can penetrate. Leave that portion unbeveled with your grinder. For instance, if the welder penetrates a maximum of 3/16 inches, you will leave 3/16 without beveling.
Step 3: Open Vs. Closed Joints
Here is the third part of how to clean and prepare metal for TIG welding. When pushing two metal pieces to make contact between them, the joint will become closed. It is good for thin metals but not for thicker ones. For a strong joint, you should lay out an open one before welding.
Open joints have a small distance between the metal pieces you will weld. The gap is less than the filler rod’s thickness. You need it to let the rod penetrate.
An open joint is trickier on its corners. You need to handle them carefully. For a corner joint, touch the edges inside to leave the gap V-shaped. The gap works as a bevel for the user to fill with beads. You have to run beads inside the corner after filling outside for even stronger ones.
If you have finished cleaning the metal, beveling the joint, and laying things out, you can finally start TIG welding. The process may seem time and labor-consuming, but it is critical to get the best weld. Skipping steps will make you pay in the long run, not to mention that it is subject to slag inclusion, breaking, and porosity.
Now, enough of learning how to clean and prepare metal for TIG welding. I hope, when it is time to act on it, you do it like a champ!