Summary for repair anodised layer Discussion
Repair of anodised layer by Alodine is discussed as a practical but limited fallback. John Smith asked whether damaged sulfuric acid anodising could be repaired with chemicals such as chromate conversion coating spray, and later said his customer would let him choose the repair process, but electrolytic repair was not possible. Brian Terry advised that chromate conversion coating (CCC) does not provide anywhere near the corrosion protection of sulfuric acid anodising, so the first step is to confirm what the customer will accept. If electrical contact can still be made, he recommended brush sulfuric acid anodising because it can produce a finish similar to the existing coating with comparable corrosion protection. The thread does not endorse Alodine/Metaflex FCR Primer as an equal substitute; it is only implied as a convenient option, with the caveat that it will not match anodizing performance.
Q. If sulfuric acid anodising damaged, is layer repairable by some process, say by some chemicals like Chromate Conversion Coating spray?
Thanks and regards
John Smith
Compact Engg Services – Islamabad, Punjab, Pakistan
2005
A. This is one of those cases where you have to go back to your customer and ask what is acceptable. Chromate Conversion Coating (CCC) will not give you anywhere near the corrosion protection of sulfuric acid anodising.
If you can still satisfactorily make an electrical contact then I would suggest brush sulfuric acid anodising. This should give you a finish similar to the current coating, whislt offering a similar level of corrosion protection.
Brian Terry
Aerospace – Yeovil, Somerset, UK
Q. My customer has left option up to me to choose any of the process for repair of anodized layer. Electrolytic repair of sulfuric acid anodizing is not possible for me. Can spray of “Metaflex FCR Primer”
(equivalent to Alodine 1200) be applied safely. It is very convenient for us.
John Smith [returning]
– Islamabad, Punjab, Pakistan
2005