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Why abrade aluminum if you are using Acid Etch

 

Do we have to abrade aluminium before applying a two pack acid etch? We at present abrade, clean with Gramos Pre-Wipe, then apply the two pack etch. I would have thought the etch would burn into the aluminum to create a bond for the powder coating, but the supplier of the etch Cromadex say it is best to abrade first.

Richard Rinn
Insight Sign Systems - Glasgow, Scotland, UK

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The better the mechanical lock, the better the adhesion. Apparently the abrasion adds a different dimension to the surface, which is enhanced by the chemical etch. You should try an adhesion test both ways.

  
Tom Pullizzi
Falls Township, Pennsylvania
 

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Dear Tom, thank you for your reply, we do get good adhesion with out abrasion but do not want to risk a problem in the future. We would like a company who manufacture etch primer to tell us 100% we do not have to abrade, or if we abrade we do not have to etch. We have been told by some companies that a product named SANDCHEM can be used with out abrasion and this is a lot less harmful, I have still to find it and see a specification in print confirming this. I will just have to keep trying.

Best regards,

Richard Rinn
Insight Sign Systems - Glasgow, Scotland