Methyl ethyl ketone – also known as MEK – is easily the most dangerous chemical we encounter in the powder coating shop.
And we encounter it a lot.
MEK does a great job of removing tough grease, adhesive residue, Sharpie ink – it cuts through almost anything, quickly and easily. That’s why we wipe most parts down with it before pretreating them. We also use MEK to check that parts were properly cured after coating (I’ll address this in a future blog).
While many powder coaters embrace MEK as a ubiquitous shop chemical, the smart ones approach it with an abundance of caution. Here’s what you need to know to stay out of harm’s way.
PPE is non-negotiable when using MEK.
Invest in rubber gloves, safety glasses, and a half face respirator with a charcoal filter, and wear all three anytime you’re working with MEK. If you can smell the chemical, your respirator filter isn’t doing its job – it should completely neutralize the acid vapors. The goal is to keep the chemical off of your skin, and its vapor out of your lungs.
Make sure the SDS is handy.
No matter what chemical you’re working with, you should have easy access to its safety data sheet. Some companies assemble data sheets into a binder. Others store them on a shop computer. Either way, the whole team needs access to them at all times. How else will you know what to do in case of exposure or ingestion?
Never transfer MEK to an unmarked container.
Hazardous chemicals should always be labeled with the product’s name, GHS pictograms, and the fire diamond. This allows the user to know not only what they’re using, but also its inherent risks. In my opinion, it’s better to purchase small quantities of MEK (1 gal cans) and leave it in its factory packaging, than to order a large drum and redistribute it into smaller unmarked jars.
MEK-soaked rags will combust if given the opportunity.
It’s happened at Kaser: we’ve had trash cans spontaneously burst into flame simply because there was a pile of wet, MEK-soaked rags at the bottom. Now, we hang them over the side of the can so they can dry without trapping heat. In the alternative, an airtight metal container designed for rag disposal would also work well.
Powder coaters, don’t let the fact that you spray a non-toxic, no-VOC coating lull you into a false sense of security. The powder itself may not be hazardous, but aspects of the pretreatment process definitely are.