Powder Disposal Revisited

We had some more readers respond to our latest discussion on used powder disposal. Following are their remarks:

Powder Disposal Revisited I

Question:

I read with interest your recent column on disposing used powder coating. Here is a trick that we use that your readers might find useful. We use turkey oven roasting bags to turn powder into a solid block. We fill the bags and put them on the floor of our batch cure oven and bake it at 450°F, let it cool and then bake it a second time to ensure that the block is fully cured. Then we dispose of the bags in our plant trash. The oven roasting bags can be purchased in bulk at most warehouse clubs. It is cheap and does a great job. T. C.

Answer:

Nice job! Martha Stewart would be proud of you and I encourage others to try your recipe, as well. I suppose that this may be a difficult disposal method if you have large volumes of powder to dispose of in a short period of time. Maybe we can find elephant roasting bags for that purpose.

Powder Disposal Revisited II

Question:

My question is how to properly dispose of contaminated powder. I was recently hired as the powder coating supervisor, and my Finishing Dept. Manager has given me the task of finding a cost effective and proper way to dispose of our “waste” powder. We are currently paying quite a bit for a company to haul and dispose of our old powder.

My past experience on another job, has been to put the powder in a 55 gal barrel and leave it in the

cure oven overnight at a temperature of maybe 250-350°F. (I’m guessing, because I worked 1st shift, and the 2nd shift would load the barrels in.) After the top layer hardened, we would dump the drums into a dumpster and our local garbage company would do the dirty work, pardon the pun. I don’t know if this is an accepted practice or not. I was the lead person then, and doing what my supervisor told me to do.

Now that it’s my hide on the line, I’m interested in finding the proper way to dispose of the powder.

I have searched the Internet and have been unsuccessful on finding any articles or information that deal with the proper methods for disposal of waste powder.

Are powder coatings a hazardous material? Are there restrictions/regulations regarding disposal of used powder, and if so, where might I find them? (I live in Northern Illinois.)

I do realize that one of the many benefits of powder coating is the ability to reclaim and reuse sprayed powder. But some powder is going to get contaminated, not to mention the small “spray to waste jobs”, eventually that powder needs to be disposed of... What’s the secret here?!? Is this the taboo subject of powder coating? M.M.

Answer:

Well first you go out and buy a lot of turkey oven roasting bags (see previous question), and then fill them up…just kidding.

Most powder coatings are classified as non-hazardous and can be disposed of the way you describe. Check your MSDS sheets for your particular powders to verify the lack of hazardous contents and disposal instructions. If all is good, then melt your worries away. Be sure to check with your trash hauler for any further precautions and weight limitations.

Other than that, I refer you to my August 2005 column when I said:

“Please be careful and use a metal container and do not put a large quantity of raw powder into the oven at one time (less than 100 pounds). This practice of melting powder coating for disposal has been discussed by myself and my fellow members of the Powder Coating Institute for years as being unsafe. We all know people do it on a regular basis, but we don’t like it. PLEASE BE CAREFUL!!!”