Proper Cleaning Solvents

Q. We spray several types of water-based and solvent-based materials in our shop. We have been struggling to find a single cleaning solvent to clean our spray equipment that would work for both. Can you recommend a good all-around product to use?

A. There are many solvents used for cleaning spray equipment, but I want to go over a few general housekeeping techniques to minimize the cleaning process of spray equipment, regardless of the solvents used. I am assuming that you are currently using many different solvents, and you want to simplify which one is the best for overall cleaning purposes. People often wait until the equipment is so crusted over with dried coatings that it becomes a tedious task to clean. I take the approach to clean as you go, so that it is not difficult to maintain clean equipment. As a general rule, Acetone is probably the most widely used solvent to clean equipment, but in certain instances it may not be the right solvent to effectively or efficiently clean your equipment. Certain oil-based products clean better with Mineral Spirits, Naphtha and so on, while water-based clean up works best with a combination of EB Glycol and water. So this brings us back to what may be the best overall product to use. If you clean as you go, Acetone would be my first choice for an all-around cleaning product. However, once products, like 2K varnishes, water-based urethanes and so on, have dried, they typically become more difficult to clean with just Acetone. This is when I bring out products such as MEK (methyl ethyl ketone). When you have stubborn dried-on products, this solvent is very effective in cleaning equipment. You will want to be certain that when using all cleaning solvents you are always wearing the proper PPE (Personal Protective Equipment). MEK in particular can be brutal on the skin, so use the proper protection. I will caution you that if using MEK, it can damage seals with in your spray guns if you soak them. I would first remove them before submersion. If needed, gently clean these seals separate from the MEK bath. I have found that MEK will do an awesome job in removing even the most stubborn coating materials. There are also methods such as ultrasonic baths that work well, but for a solvent, only the ones previously mentioned have consistently worked the best for me. I hope this was helpful.