Time for a recoat

Moderators: Erik, Chopin
Post Reply   Page 1 of 1  [ 17 posts ]
Author Message
Erik
Post subject: Time for a recoat
Posted: Sun Aug 24, 2008 8:44 pm
Site Admin
User avatar
Offline
 
Posts: 12643
Joined: Tue Feb 12, 2008 4:58 pm
Location: Off Grid in Paradise... Mag 7 skies
 
I made the mistake of cleaning my mirror without rinsing it with distilled water, and the coating got hazy. Luckily, Bob Fies at "Aluminum Coatings" in San Carlos, CA. is inexpensive, and does a great job. I'm bringing my mirror down tomorrow for a fresh coat. Probably the last one for awhile, since I'll have to ship the mirror from Hawaii in the future.

Just a reminder- when cleaning your mirror, rinse with distilled water!!! :grin:

_________________

-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


Top
Profile Quote
snorkler
Post subject:
Posted: Sun Aug 24, 2008 11:17 pm
quasar
User avatar
Offline
 
Posts: 5125
Joined: Wed Feb 13, 2008 9:16 pm
Location: Bay Area, California
 
I take it the haze couldn't be rinsed off with distilled water during a recleaning? I guess I don't understand how a failure to rinse could cause permanent haziness on a mirror.

_________________

Ah, but I was so much older then.
I'm younger than that now
Bob Dylan

[ img ]
49.6 mpg avg over 38,000 miles. 177% of '08 EPA
Best flat drive 94.5 mpg for 9.8 mi
Best tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg


Top
Profile Quote
Seantóir
Post subject:
Posted: Mon Aug 25, 2008 5:23 am
left
User avatar
Offline
 
Posts: 4297
Joined: Wed Mar 05, 2008 3:13 pm
Location: Area 14, Kildare, Ireland
 
One of the reasons I've developed a preference for refractors is the potential for problems with mirrors.

_________________

John

[quote]The Irish Constitution... is written in the present tense. You reason it in light of this year, not in light of the year in which it was adopted by the people. You don't need to hark back to what some people thought thirty or forty years ago. [/quote]Brian Walsh, Supreme Court Justice 1961-90

O....o?oo


Top
Profile Quote
Erik
Post subject:
Posted: Mon Aug 25, 2008 7:39 am
Site Admin
User avatar
Offline
 
Posts: 12643
Joined: Tue Feb 12, 2008 4:58 pm
Location: Off Grid in Paradise... Mag 7 skies
 
The chemicals in tap water damage the coatings. Once it's allowed to dry, the haze is permanent. The thing is, I know better. When I last cleaned the mirror, I simply forgot to rinse it with distiller water, which was sitting in the jug right next to the mirror. :foreheadslap:

_________________

-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


Top
Profile Quote
GeneralRageSC
Post subject:
Posted: Mon Aug 25, 2008 8:19 am
atom
User avatar
Offline
 
Posts: 44
Joined: Sun May 25, 2008 10:14 pm
Location: NorCal
 
Really? The last time I washed my mirror....I simply placed my 22" against the tree and simply hosed it down and let it runoff and dry, my coatings didn't haze.

_________________

Clear Skies,
Alvin #26
22" f/4.1 reflector, 30" f/4.3 StarMaster and Antares 6" f/6.5 on Orion SVP, 28" f/3.275 (under construction)
[url=http://www.faintfuzzies.com]FaintFuzzies[/url] | [url=http://www.observers.org]TAC[/url] | [url=http://www.tac-sac.org]TAC-Sac[/url]


Top
Profile Quote
Seantóir
Post subject:
Posted: Mon Aug 25, 2008 8:55 am
left
User avatar
Offline
 
Posts: 4297
Joined: Wed Mar 05, 2008 3:13 pm
Location: Area 14, Kildare, Ireland
 
It would depend on the water content. Aluminium is highly reactive and quickly forms an oxidized coating measurable in nanometres when exposed to air; however the the presence of some catalysts can lead to a deeper reaction and some chemicals can have a nasty effect. Salt water for instance slowly eats into unprotected aluminium and if left to react long enough the result is a vaguely green goo. This was a common problem on some classes of post-WWII minesweepers built with a composite wooden hull and aluminium frame to prevent triggering magnetic mines.

My guess would by that either your water supply contains fewer chenicals /lower concentrations or your mirror has a thicker protective coating than Erik's had.

_________________

John

[quote]The Irish Constitution... is written in the present tense. You reason it in light of this year, not in light of the year in which it was adopted by the people. You don't need to hark back to what some people thought thirty or forty years ago. [/quote]Brian Walsh, Supreme Court Justice 1961-90

O....o?oo


Top
Profile Quote
Gary
Post subject:
Posted: Tue Aug 26, 2008 8:31 am
molecule
User avatar
Offline
 
Posts: 134
Joined: Thu Feb 14, 2008 8:17 am
Location: USA Louisiana
 
Great explanation John. Thanks. I've often wondered what effect the minor amount of sea spray at the Winter Star Party in the Florida Keys has on coatings and have cringed when watching folks wiping encrusted residue from correctors and such. The stuff must be slightly abrasive is nothing else!


Top
Profile Quote
Erik
Post subject:
Posted: Tue Aug 26, 2008 3:36 pm
Site Admin
User avatar
Offline
 
Posts: 12643
Joined: Tue Feb 12, 2008 4:58 pm
Location: Off Grid in Paradise... Mag 7 skies
 
Put it this way- after looking at the local water table brocure they send every year, I'm not at all surprised that it would damage mirror coatings. :lol:

_________________

-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


Top
Profile Quote
snorkler
Post subject:
Posted: Tue Aug 26, 2008 4:15 pm
quasar
User avatar
Offline
 
Posts: 5125
Joined: Wed Feb 13, 2008 9:16 pm
Location: Bay Area, California
 
But you're in San Francisco, so your water supply should be from Hetch Hetchy Dam and the pristine Tuolumne River. ???

_________________

Ah, but I was so much older then.
I'm younger than that now
Bob Dylan

[ img ]
49.6 mpg avg over 38,000 miles. 177% of '08 EPA
Best flat drive 94.5 mpg for 9.8 mi
Best tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg


Top
Profile Quote
Erik
Post subject:
Posted: Tue Aug 26, 2008 7:55 pm
Site Admin
User avatar
Offline
 
Posts: 12643
Joined: Tue Feb 12, 2008 4:58 pm
Location: Off Grid in Paradise... Mag 7 skies
 
Pristine? Is arsenic considered pristine these days? :lol:

_________________

-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


Top
Profile Quote
llanitedave
Post subject:
Posted: Wed Aug 27, 2008 8:37 pm
Super Nova
User avatar
Offline
 
Posts: 1083
Joined: Sat Feb 16, 2008 12:06 pm
Location: Amargosa Valley, NV
 
Sodium, calcium, iron, and magnesium are the most common dissolved minerals in water. Stuff like arsenic may not be good for you, but we're talking parts per million concentrations, which would probably not be visible on a mirror.

I'm assuming the the mirror had a silicon monoxide overcoating?

If so, you probably ended up with some silicate minerals on your coating: sodium silicate, calcium silicate, and magnesium silicate all form fairly easily. There might also be some carbonates in there, with sodium and calcium carbonate being the most likely.

If the water's really bad, you might have some sulfates/sulfites in there too. Yuck!

Some of these might polish away, but I wouldn't trust them to always do so without damage.


Bob Fries doesn't overcoat his mirrors, does he? He did my 10" about 4 years ago, and I'm happy with it, but I don't remember whether that step was included.


Top
Profile Quote
Erik
Post subject:
Posted: Wed Aug 27, 2008 9:04 pm
Site Admin
User avatar
Offline
 
Posts: 12643
Joined: Tue Feb 12, 2008 4:58 pm
Location: Off Grid in Paradise... Mag 7 skies
 
I'm not sure if he applies an overcoat. I'll have to ask him. :)

_________________

-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


Top
Profile Quote
snorkler
Post subject:
Posted: Wed Aug 27, 2008 9:57 pm
quasar
User avatar
Offline
 
Posts: 5125
Joined: Wed Feb 13, 2008 9:16 pm
Location: Bay Area, California
 
??? The SFPUC's 2007 water report summary says arsenic was below detectable levels.

_________________

Ah, but I was so much older then.
I'm younger than that now
Bob Dylan

[ img ]
49.6 mpg avg over 38,000 miles. 177% of '08 EPA
Best flat drive 94.5 mpg for 9.8 mi
Best tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg


Top
Profile Quote
Square_peg
Post subject: Re: Time for a recoat
Posted: Fri Sep 05, 2008 8:31 pm
The Blacksmith
User avatar
Offline
 
Posts: 3055
Joined: Sat Feb 16, 2008 11:51 am
Location: Maple Valley, WA
 
Erik wrote:
I made the mistake of cleaning my mirror without rinsing it with distilled water, and the coating got hazy.....
Just a reminder- when cleaning your mirror, rinse with distilled water!!! :grin:



Yowsers! :shock: Thanks for the warning. I have always done the distilled water rinse but this will reinforce my habit.

_________________

Tom (Pegster)

subvert the dominant paradigm


Top
Profile Quote
fmeireso
Post subject:
Posted: Sun May 03, 2009 10:49 am
Laser Surgeon
User avatar
Offline
 
Posts: 91
Joined: Sun Apr 27, 2008 12:48 pm
Location: Eeklo - Belgium
 
What about demineralised water? Anybody has experiences with that?. I see it readibly availble over here but i cannot find distiled water easlily. Perhaps at the local pharmacie but i don't know if they are willing t provide it by the gallon....(liters)

_________________

Obsession 18 inch #1638
Orion Optics (UK) 8 inch


Top
Profile Quote
Square_peg
Post subject:
Posted: Sun May 03, 2009 6:10 pm
The Blacksmith
User avatar
Offline
 
Posts: 3055
Joined: Sat Feb 16, 2008 11:51 am
Location: Maple Valley, WA
 
fmeireso wrote:
What about demineralised water? Anybody has experiences with that?. I see it readibly availble over here but i cannot find distiled water easlily. Perhaps at the local pharmacie but i don't know if they are willing t provide it by the gallon....(liters)



Try the pharmacy. Most pharmacies in the States carry it. And it's cheap, I pay less than $1/gallon.

_________________

Tom (Pegster)

subvert the dominant paradigm


Top
Profile Quote
Erik
Post subject:
Posted: Mon May 04, 2009 12:16 pm
Site Admin
User avatar
Offline
 
Posts: 12643
Joined: Tue Feb 12, 2008 4:58 pm
Location: Off Grid in Paradise... Mag 7 skies
 
Hi Freddy,
I hope you find the demineralized water. :)

As an update to my original post, I had Bob Fies recoat the mirror and it looked great. But he doesn't use an overcoat, and I was afraid of it getting damaged again. As I was planning the move to Hawaii at that point, I didn't want to have to ship it back to the mainland to get a recoat. So, while I was still in California, I ended up having Cary from OWL strip the new coating and do a recoat with an overcoat. He's the guy that refigured the 1/2 wave beast into the 1/8.5 wave beauty that it is today, and he did a great job on the recoat as well. In fact, I was so impressed with his new facility in Sacramento, that I'm planning on writing an article about it for ATT. He has some state of the art equipment, and an unbelievable amount of knowledge on everything optics-related. :cool:

_________________

-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


Top
Profile Quote
Display: Sort by: Direction:
Post Reply   Page 1 of 1  [ 17 posts ]
Return to “Telescopes and Binoculars”
Jump to:
cron