PLEASE HELP- did I ruin my mirror?

[Corncrake]

6 hours ago, greg110902 said:

Update:

 It looks okay, everything looks sharp

Wow ! Scary stuff !!
Good to know that you have recovered it
Like the others, I am surprised, never heard of IPA doing that.

Are you sure it wasnt acetone that your good lady has been using to remove nail varnish !!
Only joking , ( I think )
It would be good to know what happened. Perhaps, for the sake of science, you should do it again and see if it can be replicated and investigated ?

No perhaps not !!!
I'll get my coat,

 

 

[markse68]

1 minute ago, John said:

I'm not a chemist either but I believe that isopropyl does react with aluminum. Which is why I wondered if this mirror did not have overcoating, or had poor quality overcoating.

 

 

Well shows what I know- from wiki “ Like most alcohols, isopropyl alcohol reacts with active metals such as potassium to form alkoxides that can be called isopropoxides. The reaction with aluminium (initiated by a trace of mercury) is used to prepare the catalyst aluminium isopropoxide.[14]“ but that’s apparently colourless but maybe 🤔

[jetstream]

My coater says to clean regularly as any organic material on the surface in conjunction with moisture (dew etc) will cause etching of the surface. I only use de mineralized water and Sunlight(mild) dish soap.

[markse68]

14 minutes ago, jetstream said:

My coater says to clean regularly as any organic material on the surface in conjunction with moisture (dew etc) will cause etching of the surface. I only use de mineralized water and Sunlight(mild) dish soap.

That’s another interesting take on it- I don’t get why we worry about the fraction of a wavelength accuracy of the figure but then aren’t concerned about a layer of much larger dust particles🤷‍♂️ Is there some physics which explains that? 
 

Water of course also reacts with aluminium and salty water pretty fast and the fairy liquid I use contains salt I think (they warn you not to use it for car windscreen washing for that reason I think) and de-mineralised water is more reactive too- agh! 😳

Lockwood has his own take 😄

http://www.loptics.com/articles/mirrorcare/mirrorcare.html

John had me paranoid about isopropyl for a moment there but now I feel a bit better 😉

[Paul M]

My personal view is that my mirrors are at greatest risk while I'm handling them and cleaning them! I'm the risk not my soapy water 

So I keep it to a bare minimum. The last mirror I cleaned was the secondary of my 250 PDS a few months ago, somehow it got a sticky finger mark on it which non of the small people could explain... Luckily it came up spotless  

 

[jetstream]

32 minutes ago, markse68 said:

but now I feel a bit better

John has much experience.

I use a soapy mixture to first rinse the mirror then use the soapy mixture again as I gently rob the primary with my fingers. The fingers allow to feel any grit and to stop and re lube with soapy water.

I use RO or distilled water for the final rinses. I use more dish soap than suggested but this gives much lube. I do not soak any of my mirrors.

Dirty mirrors cause scatter among other things. As long as there are coatings in the first place and theyre intact and complete things like acetone and alcohol can work for stubborn oil based contamination. I've used it for removing center spot glue when replacing with Catseye triangles.

DO NOT take my word on all this however, its just worked for me and my mirrors.

Edited June 21, 2020 by jetstream