The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Pretty finish close to cost and protection of anodizing AL380

My boss is having some cast Aluminum 380 parts made. I was wondering what type of protective coating would be best? The environment will be some what abrasive having to be in contact with an abrasive water based material. Most people have told me clear anodizing, but it looks very dark and not very pleasing to the eye. Is there some type of coating that will give AL 380 a pleasing finish around the cost and protection of anodizing?

Dan Schlecht
manufacturing worker - Phoenix, Arizona, USA
2003

---

2003

You are not being forthright enough about your situation to be able to get good answers here, Dan. We don't know the size of the parts. We don't know whether the number of parts involved is a handful, suitable to manual methods, or millions of parts where one extra step can be cost prohibitive. We don't have any real appreciation of the exposure situation.

If it's only a few parts, can they be made of an alloy that is more suitable to anodizing? Then the people who recommended anodizing would be recommending the pretty finish you are seeking.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

---

First of three simultaneous responses --

Sorry for not providing enough information. Each part is somewhat small being able to fit in my hand. One is a little longer than the others being about 60" in length.  The amount of parts being made will range from 1000 to 5000 parts. The parts will definitely be cast out of AL380. I was told by the design engineers that clear anodize of AL380 would look great. When we saw a sample, we all agreed that it looked dark and dull. I think we were expecting something looking like a brighter clear zinc type color.  In any case, the actual color is not that big of a deal. The color of the coating could be red. We just did not want something dark and dull like the sample we received. If you need any other information, I will try my hardest to provide it.

Dan Schlecht
Tool Manufacturer - Phoenix, Arizona USA
2003

---

Second of three simultaneous responses --

With the limited information we were given the best guess I can give is hard anodize and black dye. If done at a technically capable anodized shop the finish should meet most of your requirements based on the info given.

Drew Nosti, CEF
Anodize USA

Ladson, South Carolina

2003

---

Third of three simultaneous responses --

The problem is that AL380 doesn't anodize very well. Only aluminum is anodizable, the silicon and other materials aren't, so the result is not attractive. I think you'll need to electroplate, or electroless nickel plate, or coat the parts, and this will probably be more expensive than anodizing. Electroless nickel would probably be fine, but it's fairly expensive.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003