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Anodization Fade

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#1 BarrySimon615

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Posted 06 February 2013 - 04:20 PM

I have seen anodization "fade" on a number of astronomical parts over the years and there sometimes seems to be no rhyme or reason. I have heard things like "poor technique", "not enought time in the tank", as well as UV sunlight exposure to exposure to citrus juice as some of the reasons for anodization fading or marbling.

I have seen "cheap" equipment fade as well as expensive equipment. I have seen two anodized parts side by side for years with one part fading and the other part looking as good as the day it was first anodized. Case in point is the AstroPhysics 2.7" focuser on a Star12 ED. This scope dates from the early 90's. I acquired it about 9 months ago. As you can see from the photo - the focuser has suffered from anodization fade, while the "adapter coupling" which connectes the focuser to the tube has not faded at all.

I have replaced this focuser with an AP 9 to 1 two speed and that has essentially fixed the anodization problem as well as giving me a focuser upgrade. New focuser is very nice. See focuser in need of a reanodization, followed by a comparison to the new focuser after the old focuser has been reanodized.

Barry Simon

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#2 BarrySimon615

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Posted 06 February 2013 - 04:25 PM

Old focuser compared to the new after I had it reanodized. Reanodization did not affect fit or function. Threads were not reanodized. They were masked off with a rubber compound. Only thing left to do is to "resilver" the AstroPhysics engraving. Not sure yet just what, if anything, I am going to do with the old focuser.

I will try to get a detailed explanation from the friend of mine who runs an anodization business, in respect to what causes anodization breakdown and what you can do to minimize/prevent that.

Barry Simon

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#3 csrlice12

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Posted 06 February 2013 - 04:32 PM

Related to this is I have an Orion 9X50 RACI that I'm using on my Celestron XLT. Of course the color schemes are not complimentary (Bronze & Blue/Cream). Any idea if this could be reanondized with a different color, and any ballpark cost figures, Or can it just be painted over with enamel or something......

#4 mitaccio

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Posted 06 February 2013 - 05:05 PM

You can remove the anodizing with oven cleaner and have a silver part. Might not want to do it to parts in the optical path, but an exterior part in a silver color would look nice.

#5 Jon Isaacs

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Posted 07 February 2013 - 07:48 AM

Related to this is I have an Orion 9X50 RACI that I'm using on my Celestron XLT. Of course the color schemes are not complimentary (Bronze & Blue/Cream). Any idea if this could be reanondized with a different color, and any ballpark cost figures, Or can it just be painted over with enamel or something......


Anodizing is generally done in batches with a batch cost, around here it's a $65 minimum.

Anodizing produces an aluminum oxide surface, the colors come from the dye. I had a blue WO 66 SD that faded even though it spent it's life in the case.

Jon



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