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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Anodize vs. Powder Coat Aluminum for Waste Water Treatment Plant Railings?
Q. We are a fabrication shop. We are quoting a two line aluminum rail job for a Waste Water Treatment Plant. We are wondering if there is a significant difference between powder coating and anodizing the rails. The cost, which is very significant, is the one aspect that jumps out right away.
Christen Grinleybuyer - Pelham, New Hampshire, USA
2007
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A. Hi Christen. I would probably suggest chromating, e-coating, and powder coating. A wastewater treatment plant with acid and alkaline chemicals is probably not a good site for anodized finishes.
I give up on which one was significantly more expensive though. I have seen high quality Kynar powder coating cost more than anodizing, but less expensive powder coming in at lower prices than anodizing :-)
Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
A. But if you do powder coat, then put the chromate on very lightly. If the chromate is too heavy the high curing temperature of the powder coat will dehydrate the gelatinous coating - so just get a faint tint of iridescent yellow chromate.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina
Anodizing vs. powder coating for crutches and walking sticks
Q. Hi,
We manufacture height adjustable crutches & walking sticks, which is a better option for color finish.
Powder coating or anodising. We do not have a good anodiser who can do a quality job as per required standard, but as far as powder coating is concerned we have somebody who does a good job.
Kindly suggest, Thanks.
- New Delhi, India
January 27, 2016
A. Hi Nitin. I think you answered your own question. Reliable vendors and pragmatic issues can be as important in making your choice as technical differences in the two technologies. One of the technical differences is that white probably won't be practical for anodizing if that's one of your color choices
If you're satisfied with the looks, the durability, and the price of the powder coating, you're probably in good shape. If you can identify anything you are unhappy with, we can talk about whether anodizing can deliver it, but I think you probably already made the right choice :-)
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. Hi,
We are trying to get away from powder-coating Al7075-T6, which was done mainly for aesthetic purpose, and replace powder-coating with Type 2 class 2 anodizing with a color dye.
I would like to know whether dyeing the part will result in uniform color and texture across the part. Whether the same color can be reproduced for different parts. As all these colored anodized parts will be assembled. Color consistency is key as the product is a crew seat in aircraft.
The Main intent of replacing is for weight saving.
- Bangalore,Karnataka, India
January 28, 2016
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"Aluminum How-To" -- Chromating, Anodizing, Hardcoating by Robert Probert (2005)
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"The Surface Treatment & Finishing of Aluminium and Its Alloys" by Wernick, Pinner & Sheasby (1959 - 2001)
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"The Metallurgy of Anodizing Aluminum" by Jude Mary Runge (2018)
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A. Hi Sreekanth. Color consistency in 7075 aluminum can be quite difficult, but it is certainly possible as witness a few million iPhone 6's. Apple doesn't accept excuses.
The question really becomes whether it is practical for you to achieve. And I think the answer there is that if you can find an anodizing shop which says: "Yes, we will do it", then you can do it. If you can only find shops that say: "Maybe", then it will not prove practical :-(
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
A. Finding an anodizer that can get all of the various parts of your seat to be uniform is not going to be easy, especially on 7075.
Trying to get this months parts to look exactly like last month's parts, especially on some colors, will be rather difficult.
- Navarre, Florida
A. Hello Mr. Rao,
Yes, it is possible to achieve a uniform color shade with dyeing operation. I have a good experience of Golden color dyeing operation on Bikes 'Front Fork' outer tubes. Like Mr. Ted mentioned discipline at Anodizing process is key to achieve the same. Uniform air agitation, uniform temperature distribution, continuous filtration and homogeneous solution are critical parameters.
Surface Treatment Expert - Pune, Maharashtra
August 27, 2024
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