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What concentration IPA to distilled water?

Darth_Vader

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Darth_Vader

Darth_Vader

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Hi, Sorry for posting when there are already loads of threads discussing primary mirror cleaning, BUT...

I have read the technique suggested here -> Andy's Shot Glass - Clearning telescope lenses and the primary mirror.

The final stage of cleaning suggest rinsing with distilled water with a couple of capfuls of rubbing alchohol... HOWEVER it does not say what volume of water to mix the IPA with. Therefore I do not know what concentration I should be aiming for.

Has anybody used this technique with any success?

Cheers

DV

P.S. The primary really does need cleaning. The scope has stood for the best part of 2 decades in an upright pisition with NO cap!!!

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glowjet

glowjet

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Looking at it in the broadest sense, that this is to rinse the mirror, I should think something in the order of 30mls to one Ltr of distilled water, it is only to assist in leaving a streak free surface, as you say this has been stood open to the elements for 20 years, I do not want to sound disheartening but I think you are going to be very lucky if the atmosphere has not etched into the mirror coating :)

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obscura

obscura

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Oo! Nasty. 20 years.

For me, I'd start with a weak soapy mix and rinse and rinse and rinse, lightly removing the grime, moss, pollution and so on. No rubbing etc. This could takes some time. Then, perhaps try a 10% IPA with distilled water if, if the mirror still in good shape.

Which I guess is unlkely.

But good luck

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haitch

haitch

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Hi,

I think it is a waste of a good beer to put water, distilled or not in it.

mijijim.

:)

Have you tried looking through the mirror from the back? That might give you an idea of what condition the coatings are in - any part that doesn't look nice and shiny has lost it's coating.

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acey

acey

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To check the mirror, hold it up to the light and look at the back of it. You will probably see "pinholes" where the coating has worn away so that light can pass straight through. Even quite a lot of pinholing isn't going to make too much difference - but if you're seeing more light than dark then you'll know it needs recoating.

Regarding alcohol, I don't think the proportion is very critical - main thing is that there's good ventialtion when you do it, as you may end up feeling faint from the fumes.

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jamespels

jamespels

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main thing is that there's good ventialtion when you do it, as you may end up feeling faint from the fumes.

Presumably by this you mean a snug fitting hood of the type used when breathing in hot water fumes if you have a cold? If you're going to dilute a perfectly good pint of ale, you may as well try to get SOME benefit from it...

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acey

acey

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I've cleaned a mirror with IPA (isopropyl alcohol, not India Pale Ale) and ended up feeling very giddy and not very well.

Quote from Wikipedia:

Isopropyl alcohol is oxidized by the liver into acetone by alcohol dehydrogenase. Symptoms of isopropyl alcohol poisoning include flushing, headache, dizziness, CNS depression, nausea, vomiting, anesthesia, and coma. Poisoning can occur from ingestion, inhalation, or absorption; therefore, well-ventilated areas and protective gloves are recommended.

So joking aside, it really does need to be used with a certain degree of care.

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haitch

haitch

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I've cleaned a mirror with IPA (isopropyl alcohol, not India Pale Ale) and ended up feeling very giddy and not very well.

Quote from Wikipedia:

Isopropyl alcohol is oxidized by the liver into acetone by alcohol dehydrogenase. Symptoms of isopropyl alcohol poisoning include flushing, headache, dizziness, CNS depression, nausea, vomiting, anesthesia, and coma. Poisoning can occur from ingestion, inhalation, or absorption; therefore, well-ventilated areas and protective gloves are recommended.

So joking aside, it really does need to be used with a certain degree of care.

That's essentially what Baader Optical fluid is isn't it?

I guess the problem in this case is giving it such a large surface area by mixing with the water and swishing it around so, being fairly volatile, it evaporates quickly and gives a sudden "hit". :)

I think essentially exercise care but don't be too scared to death over it as the Wiki entry also says... "is relatively non-toxic"

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haitch

haitch

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It can be handy to have acetone around sometimes ..... but how do I get it out of my liver?

Maybe you've kept your liver purer than mine. After what mine's coped with a little acetone is the last of my worries! :)

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IanC11

IanC11

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I've used it to rinse mirror after cleaning with warm soapy water, and I just pour it over neet, holding the mirror almost vertical, in a WELL ventilated room. Then stand carefully in a vertical position until all the IPA has evaporated.

Ian

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haitch

haitch

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I'll stick with my Baader fluid then! Sounds much safer - if more expensive (It's also good for cleaning the airflow sensors on cars)

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Darth_Vader

Darth_Vader

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Thanks all for the responses...

Hopefully I will get time to look at the mirror close up sometime during the weekend. From the comments above I guess that there is no real need to worry about the concentration of the IPA. Unless of course I am talking about the Marstons variety

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