Cooked eyepiece!

[chrisp9au]

I've managed to burn out the coating on my Meade UWA 18mm eyepiece.
Removed the sun filter without moving the scope! :ashamed:
It appears to have only affected the coating on the first surface.

Is there any way of repairing the damage? :prey:

Cheers :thumbsup:
Chris

[casstony]

Expensive viewing session! I don't think you can repair the coating but the eyepiece may be quite usable with the damaged coating - have you looked through it since the damage occurred?

[chrisp9au]

Yes Tony, I have cleaned up a bit of the damage, but the view is very blurred!
I guess for the EP to be usable I need to remove all traces of the damaged coating, and I have no idea what to use to achieve that?

Cheers :thumbsup:
Chris

[dannat]

chris the coating will be difficult to remove - as it is usually baked on, you might try a solvent like acetone - but it will probably do more damage to the rubber bits/seals than it will to the coating

[leon]

Yep that will do it, not good mate but I expect the damage has been done, sorry to here of you misfortune.

Leon

[chrisp9au]

Gentlemen thank you!

I've managed to remove the damaged lens from the EP, so maybe I could try acetone, if I knew where to get acetone! Any ideas?

Ah-hah!, nail polish remover! I'll give it a try!

Cheers :thumbsup:
Chris

[casstony]

I use acetone to clean stubborn deposits off my coatings and it doesn't damage the coating.

[mercedes_sl1970]

Chris

You can also get acetone at most hardware stores.

I wonder if an optician could also give it a light buffing? But you could run the risk of the glass losing its shape. How frustrating.

Andrew

[DavidU]

some coatings are very hard indeed but as a thought I have read that Aerogard spray has ruined some eye piece coatings, so may be try soaking the single lens itself in some Aerogard. Seems like you have nothing to loose.
An unfortunate accident !
http://www.iceinspace.com.au/forum/archive/index.php/t-48533.html

[chrisp9au]

Thanks David,

Unfortunate? yes!
Stupid old man? yes!

I have nothing to lose as you say, so I'll give it a try tomorrow.

Cheers :thumbsup:
Chris

[leon]

Chris Acetone is readily available in any hardware place, good luck, and as mentioned the it can't do any more damage.

Leon

[Liz]

I know exactly how you feel Chris, as did the same at the weekend!!!
A friend lent me his solar filter and had it on my scope, gave it back without moving the scope .... Yikes.... smoke billowing out the end of EP!!
Havent tried the EP in my scope since, but it looks quite damaged. :sadeyes:
Am just glad it wasnt my new Televue Panoptic 19mm that had just arrived. :help:

[chrisp9au]

Commiserations Liz! :thanx:

Sickening feeling isn't it!

I guess we just have to be grateful it was a bit of glass and not an eye!

I've got the cleaning suggestions from this thread, and also from folks on Cloudy Nights, but don't hold out too much hope.

Cheers :thumbsup:
Chris

[casstony]

One way to avoid accidents is to have a scope permanently set up for solar - you can buy an 80mm achromat for the price of a ruined eyepiece and for a fraction of the price of a ruined eye. Since mistakes will happen, you can't be too careful with solar viewing.

[chrisp9au]

True!

Thanks Tony

[Visionoz]

Chris

Perhaps you could try your optician - I think they have access to a local point where they send clients' spectacle lenses to be multi-coated (such as Hoya Optical or AO) and cut/ground to fit the spectacle frames; I remember asking my optometrist last year and he told me about the arrangement he has with the service provider - might be worth asking!

HTH
Cheers
Bill

[chrisp9au]

Thanks Bill,

I had been thinking of talking to my optician about this.

I've managed to clean up a great deal of the problem.
I took the damaged lens out of the eyepiece and soaked it overnight in WD40!
But the view is still 'fuzzy'. Viewed under a good light I can see that there is still a faint layer of something that needs to be fixed.

I'm thinking a longer soak in WD40 might improve things a bit more.

Cheers :thumbsup:
Chris

[chrisp9au]

My eyepiece is no longer 'cooked'! :D

After some two weeks of work I have a working Meade 18mm UWA eyepiece again!

Remembering that this eyepiece was totally unusable, I didn't have anything to lose when deciding what remedies to use in trying to remove the damaged lens coating.

My first attempts were with acetone, in the form of my grand daughters contaminated nail polish remover, bright red!
This did indeed remove a great deal of the burnt brown residue of the lens coating. I managed to give the lens two or three acetone baths each day. The acetone evapourated/dried with a red residue of nail polish contaminant which, if left overnight, seemed to gradually remove more of the damage. Clean cotton buds were used for each application.

After a few days however the acetone didn't seem to be making things any better.
So I tried WD40, a suggestion from Cloudy Nights members, but I couldn't really see any improvement.
The eyepiece was still unusable, with only a small central region apparantly clear of damage.

Next step, paint stripper, and it works! The only ingredient mentioned on the tin is Methylene Chloride.

Several applications each day for a week, allowing the paint stripper to dry to a thin crust, removing the crust and carefully polishing with an optomotrists lens cleaning cloth plus lens cleaner.
The paint stripper has removed 95~98% of the damage, with just a thin 'cloud' remaining at the extreme edge of the field of view.
I'm sure another week of the paint stripper treatment will complete the process, but the weather is finally clearing up so I'm going to do some star gazing! Hopefully the good weather lasts for Border Star Gaze!

I've re-blackened the lens edge with a Sharpie permanent black marker, put it all back together and the views are excellent!

As you can imagine, I am one very relieved star gazer!

Cheers :thumbsup:
Chris

[Liz]

Great to hear Chris, what a relief!!
I havent been game to try my 40mm cooked Vixen :help: but must give it a go ... someday. :rolleyes:

[RAJAH235]

Hi...& FWIW,
You can buy 99.99% pure acetone from the chemists, as long as you tell them you're an AA (Amateur Astronomer ie; ), & what you are using it for. Costs a bit, but well worth it.

I was going to suggest you try white spirit, Chris but seeing as you've already cleaned it up......... ;)

Regs, L..

[DavidU]

Chris you can buy pure methylene chloride from sign shops as they use it to bond acrylic.

[chrisp9au]

Thanks gentlemen, I'll remember those for next time I cook an eyepiece!:D
Right now the Methylene Chloride seems to be doing a good job.

I have the lens in front of me right now, another coating of paint stripper working away, not far to go now!

Cheers :thumbsup:
Chris

[dannat]

i get my acetone from the school chemical supply - don't think we have methylene chloride..have to put in an order i reckon