What are your powder coating questions and challenges? Joe Powder, aka Kevin Biller of ChemQuest Powder Coating Research, shares his powder coating knowledge and expertise by answering questions sent in from around the world.

Hello Joe, 

Can a steel powder-coated insert work inside pressure-treated lumber? This is for an outside fence where I have a decorative steel insert placed into a pressure-treated fencepost. 

Thanks so much, 

Joe Pozeg 

Kitchener, Ontario, Canada

Dear Mr. Pozeg,
I think that I know what you’re asking. It sounds like you wonder if a powder-coated steel item that has been inserted into pressure-treated lumber will withstand the elements. There are at least a couple of issues. Is the powder UV durable? And will the powder resist the nasty chemicals that are present in the pressure-treated lumber?

As for the first question – the powder will resist fading, chalking, and corrosion if it is a good-quality polyester or polyurethane powder. Hybrids and epoxies will chalk and fade if exposed to sunlight.

Now for your second question – the powder will probably resist the pressure treatment chemicals. It’s important to ensure that the steel is clean and chemically pre-treated before applying the powder coating. Unclean steel will compromise adhesion and corrosion resistance. Pre-treatment (iron phosphate or zirconium) will enhance adhesion and corrosion resistance more so. You also need to ensure 100% coverage of the steel. Voids in the coating provide excellent sites to propagate corrosion. I hope this helps.

Good luck,

Joe

Dear Joe Powder,

We lease out a 7,500-square-foot building to a company that does powder coating. They have asked permission to build a small building next to the current building to sandblast products prior to powder coating (so they can sand blast in a contained area). 

What kind of issues should be discussed with the lessees to be sure they are not contaminating the land around the building and/or the building? What questions would I need to know to have someone inspect to see if all is OK? What kind of inspector?

Thanks,

Kara Lynn Rankin

Vancouver, Washington

Hi Kara Lynn,

Thanks for the message. These are excellent questions. Here are some issues to consider:

  • What type of media will your tenant be using? Will it be a mineral or a plastic? Plastics are generally non-toxic. Crystalline silica (i.e., sand) is a respiratory carcinogen but not a land contaminate. Aluminum oxide is rather benign.
  • What type of coatings will your tenant be stripping? Old industrial coatings can contain heavy-metal pigments such as lead oxides, chrome oxides, cadmium, and molybdenum compounds, all of which can contaminate the environment. If the stripping will only involve re-processing powder-coated parts, chances are there will be no heavy metals in the powder coatings since the North American powder industry has shunned the use of these materials.
  • Will your tenant be stripping corroded metals? Some metals or plating contain heavy metals (chromium, etc.). 
  • How will the blasting media be contained? Will the blasting cabinet be sufficiently secure to avoid airborne leakage into the atmosphere?
  • How will the spent media be disposed of? Local regulations may impact how the waste media is handled. If modern-day powder coatings are the only coating being stripped, then the waste material may be easily disposed of at the landfill. 

Who should inspect this process? Good question. Your choices include: a local representative from your state’s EPA, an independent powder consultant, or possibly a representative from your insurance company. The larger insurance companies have environmental experts that offer their services as part of your insurance coverage. I have had success using them through the years. Some state EPAs will inspect processes and render recommendations (maybe more like mandates) for the handling of emissions and effluents.

I hope that this helps you.

Good luck and let me know if you have more questions,

Joe

Do you have a question for Joe Powder? Email kbiller@chemquest.com. And be sure to listen to the Ask Joe Powder “Powdcast” for all the latest news, insights and technology in the powder coatings industry. Click here to listen!