Acid copper not bond on flash copper help

[mgcobra]

When i sand the part the acid copper peels off .

[smokeycity]

what are you plating steel ,pot metal,brass we need info

[jimcarry]

Smokeycity is right what substrate are you working with.
Then in between flash and acid copper steps are you polishing the piece or
just rinsing and moving to the acid copper. What grit paper are you using and
what kind of pressure this is a very light sanding process.
When asking a question or giving an answer we should all try to be as specific as possible

[tcam2]

You might want to check the acid copper temperature. I had the same problem until I upped my solution temperature from 100 degrees to around 120.

[KCV6]

The Flash copper is strongly alkaline. Make sure you thouroughly scrub and rinse the part before proceding to any other plating and always remember the steps of de-grease and activate if you have handled the parts in any way.

cheers