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topic 1052

Hard chrome plating books


(1998)

Q. Please tell me more about hard chrome plating, for example the ideal current density, voltage, temperature, solution percentages, etc.

I'm starting a hard chrome plant for rollers and plastic molds.

Thanks for any suggestions.

Remberto Brito
Reproqui S.A. de C.V.


Hard Chromium Plating

(1998)

A. Hi, Remberto. There are:

1). At least three quite different general types of plating baths based on their catalysts (sulfuric acid, fluorides, high efficiency etch-free). See letter 35184, "Hard chrome plating catalysts" for an introduction to that topic.

2). A large range of concentrations employed from about 28 oz./gal to 54 oz.gal.

3). A number of different general approaches, for example, tank plating with stick anodes vs. reversible rack system.

4). Rollers are sometimes plated vertically, and sometimes plated horizontally, while rotating, with the bottom half submerged and the top half above solution level.

For these reasons,
- the ideal current density may range from a low of about 1 amp/in^2 to about twice that and maybe more.
- the voltage is closely proportional to the anode-cathode spacing, so it might be only 2-3 volts or it might be 12 volts and more in some cases.
- the temperature is usually between 130 and 140 °F, but again it can depend on the other factors.
- the concentration of chromic acid is usually, as previously mentioned 28-54 oz./gal. with 32 oz./gal. probably being most typical. But there will always be catalysts in the general range of 1% of the chromic acid concentration.

For info on all this, you can try Chromium Plating by R. Weiner, or Guffie's excellent book, The Handbook of Hard Chromium Plating. =>

As an alternative you might get hold of old issues of Metal Finishing magazine and read what Clarence Peger, a strong proponent of reversible rack plating, has to say. Best of luck.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(1998)

A. In addition to looking at past issues of Metal Finishing magazine for Clarence Peger's articles about chrome plating, get a copy of Clarence Peger's books about chrome plating.

Hard Chrome Plating Simplified (CPSR) - a manual that consists of basic, simplified, hard chrome plating information to help you make greater profits; with over 200 illustrations and photographs; also includes 32 blue prints. 382 pages.

Hard Chrome Fixtures II (BLFT) a manual consisting of 80 full-color photographs of chrome shops, racked work, and other related images, 15 black-and-white photographs, 8 line-drawings, 5 papers, back issues of Hard Chrome Plating news letters, and other informative articles. Each photo has a commentary. 300 pages.

All of the information in these two manuals is based on a proven high-speed chrome plating method that produces even deposits at 0.006 + per hour plating rates. These manuals have been called the Hard Chrome Plater's Bible and the Cook Book of Chrome. If you hard chrome plate, you must have these manuals!

The manuals are available from:

Hard Chrome Plating Consultants , Inc., Cleveland Ohio

Mary Peger
Cleveland, Ohio

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Ed. note: We're happy to see you carrying on your father's legacy, Mary; and with great respect for him we've posted your reply. But otherwise, we don't post ads in these forum responses. Please become a supporting advertiser so you can advertise on this site, or try to keep responses as technical as possible; thanks :-)



(2008)

Q. Hi guys, Can anybody give me some hints of the operation costs of running a chrome plant?

Rolando Riley
- Panama


December 16, 2011

A. Hi, Rolando.

As with many businesses, labor cost is probably the biggest single item. It takes several hours (occasionally several days) in the plating tank, and the plating job often requires careful masking, building of specialized auxiliary anodes and thieves, etc.

Electricity costs can be substantial: look into Faraday's Law to estimate electrical usage based on the amount of chrome you will deposit, remembering that the chrome is in hexavalent form, and deposition efficiency is probably only about 12 percent. The air exhaust system also uses substantial energy.

The chromic acid itself is a fairly minor cost, but it can be expensive to manage the handling of chromic acid (hexavalent chromium) to avoid worker exposure and pollution of the environment.

Although it may not be easy, or even possible, it would be best if you very clearly understand chrome plating from visits to several chrome plating shops. Before you try to estimate the operational cost, it's useful to know what operations are involved. There's a saying that there are many plating shops which make good money ... but no plating shops which produce substantial rejects and make money. Good luck.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



April 18, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I have Cylindrical part OD 38.50 mm & Length 205 mm. I have problem in chrome plating. I have No Idea For JIG & FIXTURE Design for this part.

When I try to do plating to this part/job down side thickness variation. Suggest me How to do plating on this Part.

Gopal Jograna
- Gujrat, India


April 23, 2013

A. Hi Gopal. Are you racking this part vertically or horizontally? If vertical , it's possible to arrange the anodes in a ring around the part and get reasonable consistency of thickness.

When you say you have "no idea" I'm not sure how literally to take that. If you are an experienced hard chrome plater looking for a tip based on this one particular shape of this part, hopefully someone can help you. If you really mean that you have no idea about jigging and fixturing for hard chrome plating, you would need to read some books or attend some classes as it would be way beyond what anyone can tell you via a public forum. Good luck.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


April 24, 2013

Q. Dear sir

I set job in Vertical & I have all ready 1 plant This is my second plant I purchase this plant for this job its automotive part this job use in heavy truck it say KING PIN.
I need thickness 75 micron per side total 150 micron ovality & taper maximum 30 to 40 micron.
When I try this job for chrome plating and after checking this part, Ovality & taper 80 to 190 microns.
Than's & Regards

Gopal Jograna
- Gujrat, India


May 11, 2013

A. Hi Gopal: It is kind of difficult to help you without seeing a diagram or something about the part, but I am going to give you a few hints base on my experience. Hard chrome plating is a very tricky business, it is very complex and the bath is very poor in throwing, for every 100 amps you are "really" using 12 to 14 amps, with your bath in top shape. You should use 2 to 4 amps per square inch of surface to plate well.
Put your part vertical in the tank ; jig it up with heavy copper bar or hook; hopefully you have threaded holes on both ends of your part; use a stack of steel washers or nuts (to thieve the high current density of both ends, so you can get better distribution of the layer of chrome); Like Mr. Mooney said, set your anodes in a circular way around the part (use a heavy copper ring for your cell) and keep your part in the center about 3" from the anodes. Make sure your cleaning and activation process is good, good rinsing and give it a shot. This the best I can do for you. Good luck.

Nick Cordero
- New York, New York



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