OO Coatings / mirror problems

[haitch]

Just got back from holidays and turned my thoughts back to astronomy (actually turned them back Saturday when I visited the South West Astronomy Fair (nice to meet you James from FLO ).

Anyway, 1st things 1st I collected the EP from the P.O. that Philsail1 had sent and I'd missed. All in good order thanks Phil .

Next a trip to Orion Optics seemed in order to collect my mirrors that I had taken up there to have the remains of their existing coatings removed and Hilux coatings applied before I went away.

Now these mirrors are from the refurb project I am doing and really had seen better days and had complete patches of coating missing. It looked, to my untrained eye, as if it had been stored somewhere that had allowed moisture to rest on the primary which had caused the coatings to corrode away.

Picked them up all packaged and bubble wrapped nicely and brought them home. Opened up the secondary and that looks ok I think. There are 2 tiny uncoated notches along one edge where it looks to have been held in place during the coating process but I don't think that's an issue.

The primary is a different matter. I opened that up and there are about 1/2 dozen blemishes on the mirror with the largest being about half the size of my little finger nail. I've attached a couple of photos to show them (the mirror is 14" if you are trying to get an idea of the scale and the very tiny marks are just stray bits of cotton wool from OOs packaging).

I'm guessing the blemishes are caused by something that was on the face of the mirror that was not removed by the processes that remove the old coatings and clean the mirror (they are visible from the rear of the mirror). The most likely suspect I suppose, given that I think there had been water on them, is limescale or some other similar residue from the minerals from evaporated water.

Now don't get me wrong the mirror looks an incredible improvement on what it was before (it must have been missing around 20% of its coatings) but I do feel somewhat deflated having spent £255 on the mirrors to not have them back looking pristine. I would have thought that there would have been a check before applying the coatings that would have picked up on this and a telephone call would have been in order or at least hold off applying the new coatings until I had been in touch (we agreed I would ring to check they were ready before collecting)

Anyway. I'm wondering whether it deserves a call to OO or is it something I should have sorted with the mirrors before taking them in? (Although I imagine it is hard to guess what will or won't "come clean" in their process.)

How much of an impact will these blemishes have on my viewing anyhow?

Any thoughts/advice gratefully received!

Here's the photos

[Merlin66]

Did OO enclose any documentation with the re-coated primary??

I'm surprised they didn't at least make you aware that the surface had some problem ( whether it was pre-existing or otherwise)

I don't know what they use nowadays for stripping mirrors but we used to use nitric acid in the good ol' days which I'm sure would have removed everything including scale??

[daz]

I think I would be on the phone to OO ASAP!

They might easily clean off, but I think a phone call is needed to check. Do they correlate to any of the previous areas of damage do you know? As you say, it might be some residue that has not come off in the processes

[red dwalf]

you must be joking i`d be round there in a shot, you wouldn`t sell a mirror from a shop in this state, and they must have known what it`s for, they must have been blushing when they handed them over to you, do they think you would be happy with that, I THINK NOT, take them back and ask them to try again at the very least.

[haitch]

Did OO enclose any documentation with the re-coated primary??

I'm surprised they didn't at least make you aware that the surface had some problem ( whether it was pre-existing or otherwise)

I don't know what they use nowadays for stripping mirrors but we used to use nitric acid in the good ol' days which I'm sure would have removed everything including scale??

Nothing enclosed and nothing was said when I picked them up. I would have thought there was a duty of care - especially given the cost.

Anyway I've just given them a call and the guy there says it is due to salts that, because the coating was completely missing in places, have started to attack the actual surface of the glass and if I had left them any longer it would have deteriorated further.

Now I hold OO in high regard, based more on what I've heard about them than from any personal experience, but could someone tell me if I am being fobbed off? I'm just wondering if I should go and check the windows to make sure they aren't corroding:icon_eek:

[daz]

But surely the process to remove the old coatings would have cleaned these off??

[red dwalf]

if the order was for new coatings, then this is what they should have done, cleaned and refurbished as new, a phone call to trading standards seems a good idea.

[haitch]

But surely the process to remove the old coatings would have cleaned these off??

I think what he was saying is that the surface of the glass itself has been corroded.

It does sound odd to me as even with my O level Chemistry I've always thought glass to be fairly resistant to chemical attack and a salt to be a ph neutral ionic chemical reaction of an acid and an alkali?

[red dwalf]

give em hell mate, they shouldn`t take your money like that !

[haitch]

give em hell mate, they shouldn`t take your money like that !

I think I shall. I just want to be sure of what I am saying before I go in there all guns blazing.

If they haven't performed their service to standard then that is one thing but I just want to be sure about this corroded glass thing first as if they done a good job but it is my glass that is at fault I'll look wrong and stupid.

I'm guessing there are people on here who have had experience of a wide variety of optics some maybe even historic so if anyone has ever come across corroded glass in a telescope I'd love to hear about it. That'll also give OO grace until the morning as they shut at 4:30 (in 3 mins according to my PC) and this really isn't the conversation to be having with them when the guy is trying to get out the door!

[FLO]

I don't want to comment on the communication between yourself and OO but I can shed some light on the markings:

Sometimes a base coat is applied to the bare glass prior to the metal coating. When this is the case and the metal oxidises it can react with the base coat and and eat into the glass itself. A simple strip and re-coat will not fix this, if anything it will enhance the marks. From what I can see from your picture I would say OO have done as good a job as is possible.

Also, I doubt very much whether the marks will affect the mirror's performance, it least not enough for you to notice.

HTH

[adamsp123]

Salts corroding glass? I don't think so! Hell we keep all sorts of "interesting" chemicals in glass bottles.

Edit: Steve's points suprises me but I certainly wouldn't dispute it, ok but why not report it to you at pick up or before coating??

[FLO]

This might help:

Glass corrosion

Edit:

... ok but why not report it to you at pick up or before coating??

Thats why I don't wish to comment on the communication.

[Kai]

How about a second opinion from another company ???

Galvatronics i think in Essex recoat mirrors and there is another well known company who's name evades me but they are based around Oldam i think.

At least you might have some peace of mind or ammo given the reply

[haitch]

Thanks everyone for your replies - it's when it hits the fan that you need help & support and that's certainly what you get here with SGL!

Steve, thanks for that info. I'm greatly relieved to hear that I probably didn't make a great mistake going to OO but it would have been nice to have been told by OO prior to coating that there was a problem - I would have almost halved my expenditure and not gone to the expense of Hilux on a sub-perfect mirror! Nice to know that when I get round to using it that I probably won't be able to tell too.

Kai, I've sent a message to Galvoptics to ask if they've come across corrosion of glass in telescope optics just for another opinion to reassure me.

Thanks All!

[haitch]

So caught up in the coating problem I never noticed - I thought it was standard practice to centre spot mirrors these days???

Oh well, better than it being spotted somewhere other than the centre I suppose!!! (AKA LBs)

Any tips on doing so accurately without inflicting injury on my mirror? (bearing in mind it is wider than a foot rule)

[Kai]

Cut a paper circle the same diameter as the mirror , fold the template in half and then half again and snip the point off.Then use one of those white hole reinforcers to spot the mirror

HTH

[Sam]

I think you should chat with OO so they can tell you about what they did, like Steve says it might be something they can't fix, but best to let you know that.

[haitch]

I think you should chat with OO so they can tell you about what they did, like Steve says it might be something they can't fix, but best to let you know that.

I think I shall put all the things I want to say in an e-mail. That way I can think about what I am saying and not get emotive, read it back to myself and make sure I am putting things clearly and hopefully get a written response that clearly states their perspective.

If I phoned them I would probably forget to say half of what I want to and forget half of what they say to me.

Anyway I'll keep you all updated.

Cheers everyone.

[albedo0.39]

Ref Galvoptics:- When I purchased my scope, the previous owner had the mirrors re-coated by this company. Being "clever" I did some research on them and the whole market for re-coating and of course, considered Hi-lux from OO. In speaking with many people on the phone (some near professional) they all landed back at Galvoptics. The difference ? Well, whilst the Hilux options from OO is tempting, I just heard too many stories like yours.

Also, when you study Galvoptics, whilst their marketing / website might not be brilliant, the work they are involved in (military etc) has a strong reputation.

I'm delighted with the work they did and the mirrors gleam. Moreover, I have it on good authority that a certain Mr P Moore - a well known astronomer has his mirros coated by Galvoptics.

I'd be straight with OO - you expected that if there was a problem for them to tell you prior to the shipment - not after and I agree with your idea about getting a 2nd opinion

good luck - could you keep us informed ?

[Astro_Baby]

Never having been there recoating mirrors I cant advise BUT when I ran various businesses I would have felt compelled to tell a client upfront what the downsides might be.

When I was selling networks if a client asked for something that I felt would be detrimental to his network or the relationship with my company I wouild have told him so.

In this case if I were running a business recoating someone mirror and I detected a problems I'd have called to offer some options along the lines of;

a) Your mirrors knacked and you;d be wasting your money

Your mirrors knacked but if you really want to try and bring it up a bit I'll do a job on it but you'll be wasting money to have a de-luxe finishing job

c) If you really want it done to pristine I'll do it but I'm telling you now there will be defects and I'll want a sign off from you that you had this advice before we started.

d) The mirrors not too shabby but I dont thienk we can make it as perfect as you'd like. If you want a 2nd opinion thats fine and I'd encourage you to ask advice before committing.

I'd not want a customer to feel he got stiffed - its simply bad business to let that situation happen.

[teztwister]

Ive had 3 0r 4 mirrors done at Galvoptics and they have been spot on every time (no complaints)

As for OO never had anything done by them , but i would expect them to tell you before any money or mirrors changed hands that there "might" be a problem with the coating process when complete.

But to give them back to you like they are without saying a word i think is "WELL OUT OF ORDER".

I take it that you didn't have them re-aluminumise it and just coated it,maybe you could take it back to them and pay to have them re-aluminumise it then they could coat it like they should of done then you will have a 100% mirror (as long as its not to expensive)

Tez

[astromerlin]

I agree, Although the defect may have been beyond their control in the process, I would have expected them to phone and let me know there was a problem which would detract from a perfect job, you could then have had a chance to decide how much to spend.

I would think that if you were not informed that there could be defects to the finished surface then I would have expected a perfect job done.

[nitram100]

I'm just surprised there was no mention of it when they gave it back to you.

They can't seriously have looked at the finished mirror and said to themselves "Those blemishes are fine, he won't mind"

Surely with Orion Optic being experts on making mirrors they would have known it would turn out like this?

[barkis]

What is usually used to remove old coatings, is Sodium Hydroxide.

Pretty savage stuff, and you have to take great care when using it.

If you paid £255 for the recoating of your Secondary and Primary Mirrors, then you have to expect a flawless job.

Those look like splashes of the Caustic, although why they would have it situated close to a recoated mirror is beyond me.

I would have no hesitation in sending those back. If they did not issue a report with the job, they damned well should have.

With their explanation of why it ended up looking like that.

Pin holes are acceptable, but not these bemishes. Something has rejected the coating, or my previous guess on the Caustic substance.

Ron.