Welding Precautions

We all have learned that electricity takes the path of least resistance. With that said, it does not matter what type of welding method you are using; there will need to be some precautions that you must follow not to cause issues with the electrical components in the vehicle and not to injure yourself during collision repairs. Regardless of whether you are Squeeze Type Resistance Spot Welding (STRSW), Gas Metal Arc Welding/Metal Inert Gas (GMAW/MIG), Metal Active Gas (MAG) or Silicon Bronze Metal Inert Gas (SBMIG), there are some procedures you will need to follow to ensure the safety of you and the vehicle. The following is a list of these procedures:

1. Disconnect all the batteries in the vehicle. It is imperative you refer to the manufacturer's repair manual (OEM website or www.ALLDATACollision.com) for the location of the battery and/or batteries (standard, auxiliary and hybrid) and exact disconnect procedures. (Many OEMs require specific initializing procedures and specific wait periods.) Additionally, disconnect the negative cable first, isolate it with electrical tape and then disconnect the positive cable and isolate it.

2. Follow the OEM's specific procedures for disabling the Supplementary Restraint System (SRS). Some OEMs only require a one-to-three-minute wait time; others require pulling a specific fuse and some require all the SRS components to be unplugged. Regardless, most OEMs are now requiring the SRS Restraint Control Module (RCM, a general term for this article due to the various names) during welding procedures. The disconnection of the SRS RCM is to prevent electrical damage to the unit during welding.

3. If not already performed, remove any interior components and any other flammable or combustible items in the area.

4. Set up a welding screen, have a proper fire extinguisher at hand and cover the vehicle you are working on with weld blankets. Cover or otherwise protect any adjacent vehicles.

5. For areas where the weld blankets cannot be affixed, install a self-adhering weld/spark paper, such as 3M™ Spark Paper (generally used for glass and non-removable components).

6. Ensure there are no puddles of water or flammable fluids near your work area.

7. Regardless of the type of welder you will be using, position the welding machine perpendicular to the vehicle. Additionally, ensure that none of the electrical lines or electrical cables are lying on top of any of the computer modules in the vehicle. This will prevent Electromagnetic induction (EMI) from occurring, especially with STRSW.

8. Regardless of if you are using a MAG/GMA/MIG welder, ensure that the work clamp (it is not a ground clamp) is as close to the weld area as possible, and remember to keep moving the work clamp as you weld the panel on.

9. Read all the instructions, warnings and Material Safety Data Sheets (MSDS) for any of the solvents and consumables you will be using (Weld Through Primer, cleaners, etc.).

10. Remember when cleaning the weld area to first sand the area with sandpaper and only use a grinder in areas where the substrate is severely uneven. Wipe the area with wax and grease remover and make sure to properly dry the area. No liquid solvent should be present in the weld area, as the gases given off by ignition of these residues could be fatal.

Personal Safety Equipment

When performing any welding, it is imperative to protect yourself from the many hazards involved. The following is a list of the safety equipment you should be wearing when performing welding operations:

1. Regardless of the type of welding operation you are performing, you MUST wear the proper respirator. (Refer to the OSHA rules and the NIOSH under 42 CFR part 84 rule.) Not wearing the proper respirator can be disastrous or even deadly (see story below).

2. Wear leather welding jacket or sleeves, welding gloves and work boots with the laces tied and preferably the pants cuffs taped to the boot.

3. Remove all jewelry, metal objects and your cell phone. When STRSW, remove your wallet due to the EMI that may blank out the magnetic strip on your credit cards.

4. Wear close-fitting, clear eye protection goggles. The goggles are important for any stray sparks that get past your welding mask or face shield. Remember — those weld sparks are HOT pieces of metal, at temperatures up to 2,500°F.

5. Only weld in well-ventilated areas, unless you have an air extraction system.

6. Always ensure you are welding with two hands. (One hand squeezes the trigger and the other is guiding the welding gun.)

7. Always wear a good-quality welding helmet with a clean welding glass or protective screen. When welding steel, a shade or setting of 10 is recommended; when welding aluminum, a shade of 13 to 14 is recommended; and when welding with a STRSW, a non-shaded face shield is all that is required.

8. Prior to welding, always say, "ARC!" loudly to warn anybody nearby to shield their faces and eyes.

A Cautionary Story About Welding Fumes

The following is a paraphrase of an article that can be found at www.brewracingframes.com/id75.htm. A welder had a rush job one day on four diesel tanks that were pitted from corrosion. Generally, he would spray a little carburetor cleaner on the spot, wipe it off and then preheat the area with an acetylene torch to get rid of any solvents. But, on this day, the parts store where he normally purchased the carburetor cleaner was all sold out, so he grabbed a can of brake cleaner and went through his regular routine. To be on the safe side, he opened the overhead shop door and turned on the exhaust fans. When he started to weld, he came upon a severely pitted area where some residual solvent must have accumulated because as he got close to that area, a small puff of smoke was emitted. Breathing the vapors, he almost passed out right on the spot. He went outside and tried to revive himself in the fresh air. After about 10 minutes, he went to the office to look online about the warnings of the brake cleaner he used. To say the least, he was scared to death after he read the warnings: "Vapors may decompose to harmful or fatal corrosive gases such as hydrogen chloride and possibly phosgene." Through further research, he found out the active ingredient in brake cleaner is tetrachloroethylene. When this chemical is exposed to the gas argon, which is used in MAG/GMA/MIG and TIG welding, it produces phosgene. Phosgene can be fatal with a dose as small as four parts per million, basically a small puff of smoke. Symptoms can be delayed from six to 48 hours after exposure. There is no antidote for phosgene poisoning and if you do survive, the long-term effects can be chronic bronchitis and emphysema. Here are some of the issues this welder had, as well as the timeline:

1. 10 to 15 minutes after exposure: Severe, uncontrollable shaking of his left side, lasting 10 to 15 minutes.
2. A few hours later: Labored breathing (though he still did not go to the hospital or doctor).
3. Midnight: Severe coughing and chest pains.
4. The next morning: Symptoms got worse; his kidneys started to hurt.
5. Over the next four days: He was constipated and only urinated clear fluid with no smell. He felt very weak and tired; all of a sudden his urine became very dark and smelled terrible.
6. Monday (nine days after the initial exposure): He lost his balance, was confused and could barely talk (so he NOW decides to go to the emergency room). He was diagnosed with, among other things, sugar levels that were out of control, vertigo and severe chest pains. He was admitted to the ICU. After CT, MRI, EKG and EEG tests (as well as several blood tests), it looked like there was no permanent damage (at least for now), although the MRI showed fluid in his sinuses and a buildup of fluids near his brain. The phosgene scarred his sinuses and they have become infected. To this day, he still has an awful smell and taste of chlorine in his system.

What is the moral of the story? Use the proper materials for the job and protect yourself (and others) by reading all of the warning labels on the products you are using, especially if they are not intended for application. Wear a welding respirator. Even if the subject of our story had not read the warning label, he probably would not have sustained any injuries if he wore the proper welding respirator.

Hopefully, this article has brought to your attention the importance of welding precautions, vehicle safety and personal safety when welding. Feel free to contact us at any time if you have any questions.

Larry Montanez, CDA is a former I-CAR Instructor and is co-owner of P&L Consultants with Peter Pratti Jr. P&L Consultants work with collision repair shops on estimating, production and proper repair procedures. P&L conducts repair workshops on MIG & Resistance Welding, measuring for estimating and advanced estimating skills. P&L also conducts investigations for insurers and repair shops for improper repairs, collision reparability and estimating issues. P&L can be reached by contacting Larry at Office (718) 891-4018, cell (917) 860-3588, fax (718) 646-2733 or email at larrygoju@aol.com.

Jeff Lange, PE, is president of Lange Technical Services, Ltd. of Deer Park, New York (www.LangeTech.net). Jeff is a licensed New York State Professional Engineer who specializes in investigating vehicle and component failures. Lange Technical Services, Ltd. is an investigative engineering firm performing forensic vehicle examinations and analysis for accident reconstruction, products liability and insurance issues. Jeff can be reached at 631-667-6128 or by e-mail at Jeff.Lange@LangeTech.net.