Hello,

I hate rust, hate it. Unfortunately my coating knowledge is weak.

Commonly I design large steel machine weldments that have external machined features (pads or bores) that are either 1) critically toleranced 2) have high wear surfaces. Commonly in the past our company has painted the weldment and masked any of the critical machined features, and inevitably there is rust accumulation on the uncoated surfaces.

On small parts electroplating is great because of the uniform thickness and good adhesion, however on large plate this is not feasible. I do like phosphate conversion coatings with medium sized weldments because the machined pads/bores get excellent protection and the rest of the weldment is painted, however this is not economical for large weldments.

What do you do to protect external machined features on large parts? Ideally, something with very even buildup and excellent adhesion. Is there something like a local electroplating/phosphating??


Thanks.