Maintenance and Repair Cleaning

Every organization using hazardous chemicals within their facility has the responsibility to equip their facility and personnel to maintain exposure levels below the TLV. Personal monitoring badges can be used to measure exposure of a specific material. Then, depending on the threshold limit and the application, exposure can be controlled with PPE like masks, face shields, respirators, and even coveralls. If they don’t reduce exposure below the recommended limit, you will need to consider a special ventilation hood or even containment booth. As you can see, as the exposure limit gets down to a certain level, the equipment required to safely use the solvent can get impractical. At that point, your best option is to consider a safer alternative.

The personal hazard associated with a solvent is often defined using Threshold Limit Value (TLV), which is the recommended average exposure in an 8-hour day, 40 hour work week. The lower the TLV of a particular substance, the less a worker can be exposed to without harmful effects. TLV is stated on the SDS of chemical products, in additional to recommended personal protection equipment (or PPE). The threshold limit value of a solvent is generally set by the American Conference of Governmental Industrial Hygienists (ACGIH). The unit of measure is Parts Per Million (PPM). 

WD-40 is a lubricant dissolved in a solvent. While it can break down grease and oil to a certain degree, it also adds back some. This might be desirable if you are cleaning a hinge, conveyor, or corrosive-prone part, but not if you need it truly clean. For example, if prepping a surface before painting, cleaning with a cleaner/lubricant will lead to the paint dewetting (beading) or delaminating (flaking off). Chemtronics offers DPL for lubrication, and degreasers under the Eletro-Wash and Max-Kleen brands for high precision cleaning.

That depends on the requirements of your application. There are a number of factors that can have a big impact on performance and safety: flammability, dielectric strength, compatibility, toxicity, and environmental impact. Degreasers often contain very flammable alcohols and hydrocarbon solvents. They can be cheap and effective, but can dangerous without proper ventilation, or around open flames, sparks (e.g. welding), or hot surfaces. Nonflammable degreasers avoid these safety issues, but are generally more expensive. If you plan to powered equipment, or need to switch it on before the solvent has flashed off, consider a degreaser with a high dielectric strength.  More care needs to be taken when cleaning plastic packaging, plastic components, rubber gaskets and seals. If the degreaser is incompatible with the plastic, it can craze (create small cracks), embrittle, or soften the material. Rubber seals may swell, shrink, or dissolve if exposed to a harsh solvent. A new degreaser should always be tested before being used extensively. N-Propyl Bromide (nPB), Trichloroethylene (TCE) and Perchloroethylene (Perc) are highly toxic chemicals commonly used in degreasers to provide cleaning performance in a nonflammable formula. All of this has caused maintenance facilities to reconsider their solvent choices, especially with manual cleaning when exposure tends to be higher. Volatile organic compounds (VOCs), solvents that add to smog, or solvents with high global warming potential (GWP) have been a focus of a number of regulators. Some state (e.g. CARB or California Air Review Board), municipal, and even industry-specific regulations restrict the use of high VOC or high GWP materials.

Yes, it is a good idea to use gloves when degreasing. The solvents used in degreasers do a great job at breaking down greases and oils, which also happen to exist in health skin. If your hands are exposed to a degreasing solvent for enough time, oils will be drawn from your skin leading to “defattening”. Your skin will become very dry and you could eventually develop dermatitis, which looks more like a rash. In addition, some solvents like N-Propyl Bromide (nPB), Trichloroethylene (TCE) and Perchloroethylene (Perc) are highly toxic, so can be absorbed through the skin and cause issues like cancer, or impact liver or kidney function. Please wear gloves and other PPE as required.

There are no degreasers that should be taken internally, but some ingredients are more harmful than others. N-Propyl Bromide (nPB), Trichloroethylene (TCE) and Perchloroethylene (Perc) are highly toxic chemicals commonly used in degreasers to provide cleaning performance in a nonflammable formula. There are documented court cases where workers suffered major health effects when exposed to high levels of these chemicals. Workers reported headaches, dizziness, and even loss of full body control. There are also possible links to reproductive problems and cancer. All of this has caused maintenance facilities to reconsider their solvent choices, especially with manual cleaning when exposure tends to be higher.

Before you start spraying, shut down power to avoid the potential of sparks, electrical shorts or discharges, and other safety hazards. If disconnecting the power is not an option, look for degreasers with a dielectric strength above 30 kV (30,000 volts). Choosing a nonflammable cleaner would also add a layer of safety in case there is a spark.

A degreaser is a cleaner designed to remove grease, oils, cutting fluids, corrosion inhibitors, handling soils, finger prints, and other contamination common in assembly, stamping, other types of metal fabrication, refineries, motor repair, airplane hangars, and many other applications. Degreasers go by a number of different names, including precision cleaner, maintenance cleaner, and specific for automotive repair, carb cleaner, brake cleaner. The objective for a degreaser is to remove the offending soil quickly, avoiding as much wiping and scrubbing as possible.

Most contact cleaners are safe to use on printed circuit boards (PCBs) in electronic devices. Make sure the contact cleaner solvent is compatible with all components, connectors, and packaging by testing on a scrap part or inconspicuous area.

Hold object to be cleaned in vertical position so the solvent and soil can run off. Spray 4 - 6 inches (10-15 cm) from surface. Wash from top to bottom, allowing the liquid to flush away contaminants. For precision application, use with extension tube. Allow solvent to fully evaporate and dry before turning on the power to the device.

To improve the connection quality of an electrical contact or switch, you can remove oxidation or rust either mechanically and/or chemically. A brass or steel brush is the most common method of scrubbing off oxidation, although for sensitive contacts nylon is also used. With this method, take care to avoid damaging contacts and other components. It can be difficult to directly clean all the tight areas of electrical connectors and switches, so you may need to use some kind of chemical method. On the mild side, a mild acid like vinegar can be used, and other agents are offered for battery terminal cleaning, such as baking soda. Regardless of the cleaning material, care should be taken to rinse it off. A cleaner strong enough to remove rust could continue to work on unintended metal surfaces.

A contact cleaner (also called electrical cleaner, switch cleaner, electrical contact cleaner, and specific for automotive repair, battery terminal cleaner) is a solvent cleaner designed to remove contamination from electrical contacts, the conductive surfaces of connectors, switches and other electrical and electronic components with moving surface contacts. The goal is to quickly remove insulative contamination as quickly as possible, avoiding a lot of wiping and scrubbing if possible. Contact cleaning solvents are usually come in pressurized aerosol packaging for convenience and to provide a forceful spray that creates agitation and reaches into all the crevices of the connectors.

Generally, contact cleaners contain 100% solvent, which dissolves grease, carbon deposits, and other contamination, and allows it to run off. The solvent then evaporates, leaving a clean, conductive surface behind. Aerosol lubricants, like WD-40, have some cleaning ability, since the oil in the can has to be dissolved in a solvent. In this case, the solvent dissolves the contamination and a light oil is left behind. This oil can provide lubrication, allowing a connector to be inserted easily. It can also provide some hydrophobicity, preventing moisture from collecting in the connector and either causing a short circuit or corrosion. Chemtronics offers CircuitWorks Gold Guard Pen for this type of application. One problem with adding oil to a connector is it can collect dust and other contamination from the air around it.