Pre-cleaning oils from carbon steel to be Plated

A. Hello EC. It's not that the plater is unable to remove oil, it's that he is unwilling to. Twenty years ago your question would have been unheard of and considered ludicrous. The plater would certainly have taken complete responsibility for whatever had to be done to clean the tubing for his plating.

But waste disposal has become such an expensive & regulated issue these days that the plating shop wants the tubing to come to him with the absolute minimum amount of clean rust protective on it. The plater is saying "Hey, tubing vendor, don't think you're gonna solve your own waste disposal problems by just shipping all that dirty oil to me on your tubing!"

In fact, if there are no holes in the tubing and only the O.D. is to be plated, some platers today simply cap the ends of tubing and ship the oil that is in the I.D. right back to the customer :-)

So, unless you are giving the plater a blank check (and not even then if he is having trouble complying with his oil & grease discharge standards), he is not going to accept uncontrolled amounts of oil on the parts you ship him. Instead, yes, the amount and type of oil that is acceptable on the parts is often part of the specification these days.

A. Hi, Philip

If you have a vapor degreaser or know of a shop that does, it may be able to handle these parts with no labor, depending on how they are racked and how long the tubing is. But why no water?

Regards,

A. Hi Filipe. You've discovered the missing link through your experimentation with the chrome stripping tank: you need an alkaline electroclean tank after your ultrasonic bath --
It should probably be about 82 °C instead of 60 °; it should probably have a 9 or 12 volt rectifier instead of 6 volts, and the chemistry should be optimized for electrocleaning (a proprietary formulation would be ideal). You probably will no longer need manual cleaning with a cloth after installing the electrocleaning step.

Regards,

A. Hi Filipe. I was referring to the electroclean tank but higher temperature usually improves cleaning in any cleaning tank.

Regards,

A. Hi Filipe
Ted's advice is good but the alkaline clean should come before the HCl. If the parts are greasy, the acid cannot reach the surface.
There should be no need for manual cleaning. If the cleaning line did not work, a cloth will just add work and possible re-contamination.
Don't forget a water break test before plating to confirm that the parts are clean. It takes seconds and will cut down on your rejects significantly.

A. Hi again Filipe. For a while n-propyl bromide was hailed as the miracle drop-in replacement, but I have heard to the contrary since, and I don't spend my time tracking such stuff :-( There are a bunch of new proprietary solvents, such as those listed at
https://www.dec.ny.gov/chemical/72273.html
and one or more might be available and workable--although none are "drop-in" replacements. But I would not go back to vapor degreasing for steel parts anyway.

Is it possible to do the ultrasonic cleaning first as Geoff suggests, then the heavy rust removal with HCl, then the electroclean, then the acidic activation dip? That sounds very robust, and you will probably see no water break.

Regards,

A. Hi Filipe. You didn't need to post pics of grease-stained parts for us to believe that inadequate cleaning leads to defects. Just be aware that virtually every production plating shop employs electrocleaning these days, and virtually no production plating shops do hand cleaning anymore.

But your pictures do help us understand your specific components :-)

Thanks & Regards,

 Pictures were just to include context :) I have been putting pressure on management to see if they update our degreasing procedures. With your help, maybe they will start listening. Thank you.