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Bresser Corvette cleaning by Action Optics (1 Viewer)

mark clements

New member
Got my late 80s / early 90s 10x42s back from Action Optics today.
They're my spare pair for the car boot, and also lent to youngsters, and they'd developed fungus over the years.
Excellent cleaning, but still a little etching had left me a bit concerned.
No need to worry, clear and bright for their age and coatings. And the etching was not visible at all. My quick grab car bins and god children's bins are back.
Thank you Action Optics, nice job.
Harry :t:
 

Binastro

Well-known member
If polishing is too deep to remove etching, then this will affect the surface figure and performance.
So it is a question of judgement how far to go.
 

mark clements

New member
I'd guessed as much, binastro,
So was a bit concerned prior to use yesterday, which included very bright sun, reflected light and dark shadows, so was impressed that performance (ok they're not Zeiss or Swaro) seems unaffected. As much as anything it was a 'what have I got to lose' call for the clean, versus cost of new. The etching has no obvious impact on my view.
Action Optics priced it well and did a good job; new, similar quality (these were the Japanese made Corvettes) would have cost at least 5 times the cost of cleaning.
If they were my main bins, currently number 3, I'd have gone new, for all of the right reasons, I'm pleased the old faithful have a renewed life.
 

Binastro

Well-known member
I had a very old Swarovski Porro with serious fungus.
This had similar work done but the two barrels show completely different colours, although resolution is O.K.

I also had a TTH 20 inch f/5.6 Aviar lens with bad fungus.
I used Brasso and toothpaste and destroyed the surface finish in about a minute.
Star testing afterwards showed how much damage I had done.

With a scrap lens maybe try Oral B Sensitive as I think there are finer particles.
Useful for learning purposes if one knows how to star test and one can see the results.

But in short, leave it to an expert.
 

richard866945

Bino repair man
There is always a fine line between rubbing the coatings to remove the fungus or leaving some of the fungus and all of the coating. We try meths first and that normally does a good job but it is likely that the fungus has "eaten" some of the coating and will leave a slight stain. If the staining is really bad then it is worth removing all of the coating to avoid the light scatter / distortion that the fungus stains will cause.
 

mark clements

New member
There is always a fine line between rubbing the coatings to remove the fungus or leaving some of the fungus and all of the coating. We try meths first and that normally does a good job but it is likely that the fungus has "eaten" some of the coating and will leave a slight stain. If the staining is really bad then it is worth removing all of the coating to avoid the light scatter / distortion that the fungus stains will cause.

from your location, Richard, I presume you cleaned them.
Excellent job thank you.
Harry:t:
 

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