The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Powder peels from aluminum rims at bolt area

2003

Dear Sir,

Re. Powder Peel Off at Bolt Area

We are a manufacturing company of Aluminium Rims and Aluminium Actuators . The problem we face is powder paint peel off at the bolt area. The powder is Polyester TGIC Free an the Curing Time is 200 °C at 10 Minutes. If the Temperature is set to 240 °C the Colour becomes Darker. Please Advice Us. Your kind cooperation is much appreciated.

Thank You, Yours Sincerely,

Batummalai Vellayan
Engineering Officer in Alloy Rim and Aluminium Product Manufacturing Industry - Seremban, Negeri Sembilan, Malaysia

Dear Sirs,

Your question informs us that the defect is confined to the bolt area.

As a manufacturer of powder coating materials, we would investigate why this is and experiment to eliminate the probable causes.

1) after your normal cleaning process once again clean with a solvent (a) Xylene ⇦ this on eBay or Amazon [affil links] , (b), MEK / methyl ethyl ketone, (c) boiling water. Clean only a few bolt holes leaving the remainder untouched. Use the different solvents on separate components. Then powder coat as normal. Test for adhesion areas around x-clean and normal.

As described your problem appears to be one of cleaning and finding the right method. Check if the lubricant you use for creating the bolt holes does not contain silicone, some do and you will have to find a non-silicone type.

regards

Terry

Terry Hickling
Birmingham, United Kingdom