Every month, we take a common question about powder coating and get an answer from our resident coating expert, Bruce Chirrey. If you have a question for Bruce, please send it to firstname.lastname@example.org.
Question: Occasionally I rub or scratch the fresh powder coated finish off of a small section of a part by accident while working with it after it has been coated. Aside from buying touch up paint to match the color I chose, is it possible to make a spot filler from the powder I was using? Someone I work with suggested using some rubbing alcohol and maybe a spoonful of powder to make a slurry, then applying it with a paintbrush and letting the alcohol evaporate before rebaking. Will this work? Thoughts on this or do you have a better suggestion? The areas I want to fill can be as small as a 1/16” square.
Answer: Touch-up can be tricky with powder coating. The alcohol method can work but might give you an unexpected result. Applying powder to the primary visual surface by any method other than respraying can give a halo-effect, a shimmer, or an uneven surface that may draw attention to the touch-up rather than disguise the original defect.
My simple answer for touch-ups is if it can be recoated, go ahead and recoat the whole part but with much less powder than was applied during the original coating. That way you have a consistency of powder film all the way around the part and no weird surface inconsistencies. If you just put a little powder in a corner, that’s different than on the prime visual area of the part. I have done corner touch-ups with q-tips and small brushes without the alcohol by applying powder to a part after it has been heated, then rebaking it at curing temperature for a few minutes. If you use the alcohol method, make sure the alcohol is completely evaporated. Otherwise, the touch-up and surrounding area can wrinkle.
Thanks, Bruce! If you’re having issues with your finishing results, please give us a call. Bruce and our other specialists can troubleshoot your process and help you get the best finishes possible. Contact us today.
If you are looking for more powder coating information – including tips and tricks, troubleshooting guides, and equipment maintenance schedules – check out our Resources page.