44082

Paint prep concerns when changing from Hex Chromium to Tri Chromium plated material?  

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Our Company has recently changed from a Hex Chromium plated Z-grip galvanized Steel to a Tri Chromium process. Using the same paint prep techniques, we ended up with a contamination "smearing effect" under the paint when using reducer to clean the part prior to paint. This was eliminated by changing our process to cleaning with a T-24 and then a reducer prior to paint.

My question is, are there any chemical differences between Tri and Hex Chromium plating that would leave a residue and effect a painting process or is this likely a rouge contaminate?

John McNeely
Electro-mechanical Manufacturuer - Florence, KY, USA

Why are you painting chrome plate?? I suspect that you mean chromate treated aluminum or zinc plate. Am I correct??

James Watts
- Navarre, Florida

Yes you are correct

John McNeely
- Florence, KY

It is not uncommon for platers who've "gone trivalent" to introduce a post chromating step, frequently some kind of sealer. This gives the parts better salt spray resistance. These sealers are rarely if ever applied to hex chromated parts. That might be the difference.

Dave Wichern - The Bronx, New York