Hard Chrome Problem

[pppoffice]

I am having fits getting the hard chrome to stick to my metal parts. I am trying to put appx. .005 of chrome on a part that we have ground on centers to remove grooves worn in by seals. A good deposit of chrome is going on the part but when we try to grind it to size it flakes off. The parts start off as ground then rinsed in DI water then etched in battery acid for 60 seconds then rinsed again prior to putting into tank. Run with polarity backwards for 60 seconds at one amp per sq. inch. Run with polarity normal for 60 seconds at 1 amp per sq. inch then turn amps up to 2 amps per sq. inch until desired thickness achieved. Parts come out somewhat rough and when I try to grind to size the chrome chips off.

HELP!!!!!!!!1

[jimcarry]

Re: Hard Chrome Problem

I am having fits getting the hard chrome to stick to my metal parts. I am trying to put appx. .005 of chrome on a part that we have ground on centers to remove grooves worn in by seals. A good deposit of chrome is going on the part but when we try to grind it to size it flakes off. The parts start off as ground then rinsed in DI water then etched in battery acid for 60 seconds then rinsed again prior to putting into tank. Run with polarity backwards for 60 seconds at one amp per sq. inch. Run with polarity normal for 60 seconds at 1 amp per sq. inch then turn amps up to 2 amps per sq. inch until desired thickness achieved. Parts come out somewhat rough and when I try to grind to size the chrome chips off.

HELP!!!!!!!!1

Honestly the only time I have had this problem I found that if I left the part in my de greaser longer the problem went away now I leave my stuff in the de greaser for 30 min some times longer

[fxstcguy98]

Re: Hard Chrome Problem

I'm no hard chrome expert but it sounds like a prep problem. I noticed that you do not have a degreasing step in your prep. Degrease with a hot alkaline cleaner and make sure you pass the water break test. Just a thought.

[pppoffice]

Re: Hard Chrome Problem

Thanks for the ideas. I use to use a degreaser from Caswell and was having the same problem. I finally spoke with the owner of Caswell one day and he said to NOT use the degreaser as my parts were freshly ground. He had said just rinse in DI water and etch in battery acid. I have done it this way now for quite a few parts but I am still having the same problem as before when I was using the SP degreaser from Caswell. The chrome will build up the thickness I need but as soon as I start grinding it to size, it flakes off and blisters. It definitely isn't adhering to the steel. I use to have a company in KC, MO do hard chrome these parts for me and their hard chrome stuck just fine. I'm sure it's something stupid (probably me) but it is driving me NUTS.

Mike

[mcaswell]

Re: Hard Chrome Problem

Try reverse plating in the chrome solution for 15-30 seconds, at the same rate you woulod plate it. Then immediately flip the switch and start plating. This will etch the part.