Finishing Talk Forums - The Online Surface Finishing Community - Dummying Tanks before Starting electroplating

Re: Dummying Tanks before Starting electroplating

info@finishingtalk.com (DustinGebhardt) — Mon, 19 May 2008 22:16:41 +0000

Those type of panels tend to work very well. They can also be rotate 90 degrees to help remove shelf roughness in a pinch. The smaller you make the "shelves" the more uniform the surface area will be, and generally the more effective the panels will be. This will allow you to HCD dummy the bath without affecting the LCD chemicals, and vice versa. With panels that have larger folds, you tend to build up a lot of plating on the corners and very little in the concave areas, making the panels less efficient.

Re: Dummying Tanks before Starting electroplating

info@finishingtalk.com (Finishing Market) — Sun, 18 May 2008 17:25:41 +0000

Hello Harold,

As far as I know you can use almost any kind of compatable material to perform this dummy plating. You can see in the pics below that these Dummy Plates have been fabricated so as to maximize the surface area.

<img src="user-uploads/Finishing-Market/DSCN7188.JPG" />

<img src="user-uploads/Finishing-Market/DSCN7185.JPG" />

Attachments:

DSCN7188.JPG
DSCN7185.JPG

Re: Dummying Tanks before Starting electroplating

info@finishingtalk.com (DustinGebhardt) — Sat, 10 May 2008 20:57:10 +0000

Dummying is the common term for dummy plating, or using a scrap piece to plate, usually at lower or higher then normal current densities.

If you were constantly nickel plating zinc or copper or brass parts, you would frequently dummy plate the bath at low current densities to PREFERENTIALLY remove the copper and zinc. Normally, the dummy has a large surface area, to maximize the amount of material removed. In my experience, a large piece of corrugated sheet metal is used with a current density close to 5ASF or lower.

There are other uses for dummy plating. In a hex chrome bath, it can be used to remove chlorides and activate the anodes. These dummies are usually very small to prevent the buildup of tri chrome. You can also perform a high-current density dummy plate to remove excess brightener.

A separate dummy tank is usually one that is used to perform the dummying in. You can also do a continuous dummy, where you use a small tank with a separate rectifier, anodes, and dummy panel to perform the dummying continuously. Usually, you pump the solution into the tank, which is higher in elevation than the main tank. As the dummy tank fills, it overflows back into the main tank. Many platers use them in high-production shops to minimize down time.

One thing to consider with the current price of nickel. While dummy plating targets a certain contaminant (usually), you are still plating a majority of your normal metal. That is to mean, in a nickel bath, you can try to dummy out zinc, but the majority of the deposit on the dummy panels will still be nickel. The zinc content will be higher than on a normal deposit, but it will still be mostly nickel.

Dummying Tanks before Starting electroplating

info@finishingtalk.com (Harold Evans) — Fri, 09 May 2008 06:46:53 +0000

What is dummying tanks? How is it done? What happens to the anodes while dummying is going on? I will need to answer my students questions in the near furture.