Poor paint adhesion on 304 stainless fasteners

We are spray painting a 304 stainless steel cap attached to a carbon steel fastener. The paint adhesion is a hit or miss. We have tried several pre-paint things to improve adhesion such as blasting, phosphating as well as a primer before finish but no luck on consistent paint adhesion. Do you have any suggestions for preparation before finish or a finish paint that will give a consistent paint adhesion?

Thanks for your help

Carl Lutz
Fastener MFG - Reading , Pennsylvania, USA
2004

An adhesion promoting rinse is one thing that will help bond coatings to stainless. I've used this process for many years on truck tool boxes with a stainless hinge attached to a mild steel box. Contact your phosphate supplier about these products, all of the larger suppliers and several smaller ones have the technology.

Jeff Watson
- Pearland, Texas
2004

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