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Hexavalent chrome tank no longer plates

adv.    

Hi All,
Where do I start, our chrome plating tank has decided to stop plating or if any extremely little coverage. We have had the solution analysed by our chemical company and were told that the tri-valent was quite high. We are currently working this down. We also needed to add a controlled amount of barium hydroxide to reduce the sulphate content.

I seem to be able to plate small parts without too much effort but any reasonable size part does not chrome or has unbelievably low coverage.

I currently have 8 anodes in the tank 2ft by 1" round.The tank dimensions are 3 ft x 3 ft x 2 ft deep. Any ideas would be great as I am at my wits end with it.

Best regards,

Craig Short
Chrome plating - UK
2005

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2005

Ref handbook-
1-check sulphate if high
2-check current if low
3-check temperature if high
good luck GOD BLESS

Khair Shishani
aircraft maintenance - Al Ain, UAE

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Waste not want not. Put in a very small cathode area and blast it with high current dummying for a day, say 1500 amps /sft till your bath plates again.

We use a small steel pipe.

Ensure a chocolate colour on the anode. If the anode is yellow your bath still won't work. Thereafter do this for an hour every day in the morning for trouble free operation.

best Regards,

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

2005

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First of two simultaneous responses --

HI CRAIG !
YOU HAVE HEXAVALENT CHROME PLATE PROBLRM?,CHECK THE ANODE IT SHOULD BE BROWN COLOR IF NOT YOU HAVE TRIVALENT CHROME BUILD UP IN YOUR CHROME BATH,THEN YOU HAVE TO CLEAN ANODES AND DUMMY TO CHROME BATH WITH USING LESS AREA CATHODE AND HIGH CURRENT.YOU NEED 1.5:1 RATIO MEANS 1.5 ANODE AREA AND 1 CATHODE AREA.IF YOU HAVE LESS ANODE AREA POSSIBILITY TO BUILD UP TRIVANET CHROME.CHECK SULAFE IN YOUR CHROME BATH.IF sulphate HIGH USE BARIUM CARBONATE TO sulphate DOWN.MAKE SURE TEMP.OF CHROME BATH IS IN SPEC.

Popatbhai B. Patel
electroplating consultant - Roseville, Michigan
2005

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Second of two simultaneous responses --

IF you are not doing your own chrome/sulphate/trivalent testing you need to set up your own lab. Look up Kocour for simplistic test equipment.

The information that you have been given is correct, but it leaves out what you are plating ID's or OD's or flats. You need at least 2 times the anode area as the normal cathode area or you will generate tivalent chrome.

Porous pots work great for keeping tramp metals and trivalent to proper levels. Your tank is a bit small for any but the tiniest ones. Talk to Hard Chrome Consultants in Cleaveland, OH for the most affordable rudimentry ones that I have seen.

James Watts
- Navarre, Florida
2005

adv.