Adhesion test for chrome plated towel warmers

A. There are many ways to test the adhesion of chrome plating. You apparently are the designer and supplier, so you get to decide for yourself which is most appropriate. The easiest--if you can convince yourself that the samples are fully representative--is to plate a sample strip along with the radiator, then bend the strip over a round mandrel of a decided-upon diameter and pass the radiator if the sample strip does not crack or peel.

Due to the relatively high cost of simply throwing away a poorly plated part, and the environmental difficulties of stripping nickel from the defective parts, it is common practice when parts don't look good to just strip the chrome, activate the nickel, and re-nickel and re-chrome. I would suspect that adhesion troubles are much more of a problem on these replates than on new work; a routine practiced by bumper shops is to identify the replated parts and only give them one shot at replating -- both in the belief that more than 2 layers of nickel would be too much, and that if you've tried unsuccessfully twice, there may be something wrong with that particular part which would cause the plating to fail a third time but isn't worth investigating.

A. It is common practice to strip the chromium and replate them (usually only once). But you need to reliably activate the nickel, and you need to serialize the defective parts so you don't waste time and money repeatedly try to replate a particular part that just won't plate right :-)

A. It is a decorative part so it is probably not a chrome plating but a nickel layer of 20-25 microns plus 0.25 microns of chromium.

In this case there is no adhesion problem between the chromium and the nickel but between the base metal (what is it, steel or brass?).