Slightly OT: Anodising experiences?

Hi,

For the last few weeks I've been receiving production-prototype runs of alloy components with a "clear" coating, i.e. a natural silver finish, the coating is there for environmental protection.

The thing is, every run has looked different... The first run had a lovely "crisp" slightly synthetic quality to it, and I liked that and ordered more... So far each following run has looked "grey" and somwehat "cloudy". The last run is fairly crisp, but you can see considerable grain running through the finish, whereas the first run had no grain and looked great.

I'm now getting to the point where I'm thinking anodising may not be worth it, a plain alloy with lacquer may be a compromise I might have to accept.

The engineering firm machining the parts tell me that the only way they can guarantee a homogenous finish between runs would be to use aircraft alloy, which is not an option as a/c alloy costs several times as much as conventional 6082 bar-stock.

I have a terrible feeling the machinists didn't anodise a sample of bar-stock prior to the main-run, and consequently they have made many hundred in the bar-stock other than the initial prototype bar-stock, and they are now trying the get rid of the parts to me as they don't want to write them off...

Has anyone here had trouble with consistency in anodising? I know it would not be such an issue if I went for a colour such as black or red etc, "plain" or "clear" anodic coatings seem to cause the most trouble with regards to consistency.

So the question is: do I persist with anodising, or lunch-it and go for for plain alloy with a lacquer to protect?

Any wisdom with regards to anodising would be gratefully noted.

Thanks,
Justin

A friend of mine used to work for a Santa Clara, California firm called PK Selective. They made the anodized front panels for some of Emu's rack mount processors and the owner is a certified vintage pro-audio gear nut.

I would think they would be worth talking to at least to get another opinion on how viable it is to get a consistent finish you're looking for.

Yeah, someone told me once that the hardness of the alu affects the anodising finish, so it might have been different stuff.

ANODIZING FOR AMATEURS:

http://archive.dstc.edu.au/BDU/staff/ron/meng/anodizing.html

Jakob E.

justin-

nearly everyone I know who has been involved with anodizing on a production level has had a similar story to tell when dealing with any finish other than black. Ive gotten some cutsom anodizing done in the past and asked about matching in the future and was told to do it all at once to get it exactly right. I dont think thats all too uncommon.

dave

Thanks for all your comments guys :guinness:

nearly everyone I know who has been involved with anodizing on a production level has had a similar story to tell when dealing with any finish other than black. Ive gotten some cutsom anodizing done in the past and asked about matching in the future and was told to do it all at once to get it exactly right. I dont think thats all too uncommon.

Click to expand...

That's what I was expecting to hear, it's reassuring to hear others have had the same issues.

I went to another anodising firm today to pick up samples, and their finish was no better than the others I've tried. The only suggestion the anodisers could make was to obtain a sample of bar stock from the wholesalers before purchasing, then anodise to check results. I'm guessing the samples I was so happy with came from a non-descript bar the machinists had lying around...

The machinists are getting highly pissed off with the situation, and their quality and price is good so I'm reluctant to get too heated with them. I still think they should have documented the prototype process though...

Next stop is lacquering bare alloy; not quite as cool or "bespoke" as anodising, but sufficient I guess. A lot of turned / milled alloy I see on audio products tends to be lacquered (clear anodising tends to be more common on panels), maybe they know something I don't...(or am learning).

Ever wanted to know where Focusrite get their RED panels from?
http://www.alphaanodising.demon.co.uk/

Thanks again,

Justin