Need help hard chrome plating an internal diameter...

[ld2222]

Any ideas on this problem would be appreciated...here are the details:

3.6 sq.in surface area to coat on ID
7.2 A
12V car battery with charger
Resistance with bulbs in parallel
3 hours plating time
surface cleaned very well and water break tested

The result is very little plating. I have plated sample parts to test the batch and have good results, but cannot get ID setup to work. Please click this link if you want to see pictures. Click on the pictures for a larger view. http://home.earthlink.net/~sc.co/

[dadkar2]

My only suggestion would be to get an anode on the inside of the part you're trying to plate. One common theme with chrome is that it doesn't have much throw. So, you have to get the anode up near where you need the chrome. Make an anode that will fit inside the area and yet still has enough surface area. Bending a piece of 316 SS sheet into a cylindrical shape is one way. The SS doesn't have to be very thick since it doesn't erode in the plating tank. .018" 316 SS can be bent up pretty well. Or find a piece of 316 SS rod stock perhaps .5" diameter.

Put an anode bandage or bag around the anode in case you accidentally touch the anode against the part while it's in solution.

If you are going to attempt this with a hand held anode (not recommended), make sure the area is well ventilated!! Don't breathe the vapor from the chrome plating process. It's not good for you.

Ken

[ld2222]

Thank you for the info. I casted a 1/2 diameter column of chrome anode, but did not get good results. You can see the anode inserted into the acrylic jig in the pictures. I chose 1/2 inch according to the manual, page 84.

I did not know that I could use stainless steel as an anode. There is no mention of that in the manual. I will try a large disk of stainless or cast anode, diameter 1.5 to 2 inches to plate a 2.290 inch internal diameter.

I did not know that chrome plating had poor throw. I'll try the larger anode and let you know how it goes. If there are any other problems with my setup please let me know.

http://home.earthlink.net/~sc.co

[dadkar2]

Sorry I cannot read the drawings on your website. They come out fuzzy and illegible.

Are you sure you're using enough current?

Ken

[ld2222]

You can get a better view of the pictures if you click on them. The anode can be seen in the center of the clear acrylic puck. Regarding current, I am doing it to the book, 7.2A measured.

[dadkar2]

I see it better now. Make sure you're getting enough agitation around the area you want plated. Any electrolytic reaction will be aided by agitation.

Is it possible that the chrome in solution is trapped in that little well and it is depleting of ions before you get any significant plate buildup? Just some thoughts.

Ken

[ld2222]

The setup has good agitation and free flow. The mixture bubbles under power. I think the problem is throw as you mentioned, but cannot say yet since I have not run another test. I will let you know. Thanks again for your help.