8 replies to this topic

[Oregon-raybender]

Just a thought.
 
I watched a number of folks using hand
sprayers in their videos, squeezing the pump, it
looks hard to control. They had successes, but after a while
you hand will numb (?) and the amount material will vary,
which will cause issues, some that may be explained by this method.
 
Having silver coated hundreds of optics using a professional
spray systems (Peacock) and their chemicals. I would
like to offer a suggestion. Perhaps using a electrical stain sprayer

that are available. If I was to decide to coat mirrors
again, I would spend the extra money and use a couple of them.
One with activation, and two for the silver. For distilled water
a weed sprayer. The spray would be under better control.
I would love to see a dual unit for the silver, I great success
with them.
 
Maybe someone has done this already, was it successful?
 
Looking at how to improve the current process, I would go that way.
Well, there is my take on the process, make it easy, sure the extra expense
is there, maybe a group buy in?  Have a coating party.
 
I'll leave it here for others to check into this.
 
Starry Nights
 
https://www.wagnersp...rol-stainer-150

 

 

 

 

[Bob4BVM]

I like it Bob !

 If I were coating silver as a business, such a setup  would make sense.

But, at least for this poor ATMer, even the AG pump-up sprayers were a bit rich for my blood.

So I started out using what I knew, the typical pump-up weed sprayer, which i might add, looked suspiciously like the official AG sprayers.

 

My coatings kept getting better as I learned from experienced folks like the OSW group, especially Howard and Mel.

Add to that my 6 or 8 attempts to date, and i began to get very good coatings, except for my ever present nemesis, the dreaded blue haze.  In desperation i started looking more closely at my process, and all the notes i had taken from the experts i talked to. Having  a pile of window pane glass in my shop, i started changing things one at a time to try to discover where the haze was coming from.

Rob at OSW and I were discussing what the haze actually is, with suspicion it's early/uncontrolled growth of excess silver crystals on the glass, which seemed likely seeing as how i could wipe it off if done immediately after spraying, which was OK for small pieces and test glass plates.

But try as i might i could never get it all off before it (apparently) "set" on larger pieces like my 17.5" BT mirrors.

 

Finally i noticed that the nozzles on my garden sprayers, even when pumped up well, though producing a fine spray, had a few little coarser "squirt streams" here and there in the otherwise even spray cone. 

That led me to wonder if i was getting enough local inconsistency in the spray cones to disrupt the 1:1 ratio needed for the Silver and Reducer sprays to work according to the AG chemistry requirements.

  I was very carefully measuring my S & R solutions, but was I negating all that care by spraying the solutions at an uneven ratio ?

Of course I calibrated the S & R sprayers for equal volume per time, but could there be local inconsistencies in the actual spray cones which negated all that care ?

Such local inconsistencies would be missed by a simple spray volume vs time calibration.

 

With that in mind, i started looking at other sprayers, with a goal of getting the finest, most consistent spray cone possible, with no local inconsistencies visible in the spray. 

I have a compressor & gun setup for spray painting which satisfies that, but as they say, water and oil (nor paints ! ) do not mix, so i was loath to be running the AG chemicals thru that system, not to mention i'd need a second sprayer setup .

 

After trying several different wands and tips on the garden sprayers i had been using, I came across these little 48-oz pump up sprayers. Testing with water, I was happy to find I could get a beautifully fine & even spray cone if i cranked the tips in tight and pumped the bottles up 100X.

So with two of those in hand, I mixed a small batch of the AG chem's at a thin (54:1) ratio, cleaned a piece of window glass, and gave it a shot.  To my delight the coating went on beautifully even, developing slowly to a bright silver, with no trace of my dreaded blue haze, an enormous first for me !

After that I silvered a 4.25" Secondary for the BT and a 4" flat for a folded frac project.

Both came out 100% perfect, very bright, & zero Blue Haze ! 

 

I have not re-done the 17.5 pair yet, but now at long last,

i am confident i can get a perfect coating with no haze.

 

For anyone wanting to try them, the little sprayers I used are Chapin #1002, 48 oz, White bottle with red pump top.

Our local BiMart has them for $13, often on sale for less.  Way easier to handle, no hoses and wands, no hand trigger spraying. And the price is a final bonus

 

Best,

Bob

 

Edited by Bob4BVM, 18 March 2025 - 07:44 PM.

[Tom Stock]

This is an interesting post thanks for sharing.  I always assumed the blue haze was from temperature being too high causing the reaction to happen too quickly.

 

At least thats what I gathered from what I had gleaned from reading many many articles from the old books, and from my experience trying to deal with the blue haze. 

 

I waited for cooler weather and got a perfect coating on the first try with plan old hand sprayers.

 

Now, it could be that the uneven spray is what contributes to the issue at warmer temperatures, no idea, but if a more even finer mist helps reduce the odds then I am interested.

 

I'd like to hear more results.

[Bob4BVM]

This is an interesting post thanks for sharing.  I always assumed the blue haze was from temperature being too high causing the reaction to happen too quickly.

 

At least thats what I gathered from what I had gleaned from reading many many articles from the old books, and from my experience trying to deal with the blue haze. 

 

I waited for cooler weather and got a perfect coating on the first try with plan old hand sprayers.

 

Now, it could be that the uneven spray is what contributes to the issue at warmer temperatures, no idea, but if a more even finer mist helps reduce the odds then I am interested.

 

I'd like to hear more results.

I've sprayed at all temps from 80  to 45F, Blue haze every time.

That was with the garden sprayers.

To date i have done 4 pieces with the new sprayer. No haze on any of them. Difference is night and day for me

Bob

[ccaissie]

Thanks for this.  I too noted the uneven droplet size with two Homedepot hand sprayers.  By rotating the mirror frequently, spraying heavily in bursts, and keeping the temp low, I was able to usually get a good hazefree coating.  I will source the better sprayers.  Thanks.

https://www.amazon.c...PDKIKX0DER&th=1

 

But while learning the methods and coating dozens of pieces, I have used up almost all my Angel Gilding stuff, and loathe to buy more.  I just bought Ammonium Hydroxide and made 90g of Silver Nitrate from 2 silver bullion coins and nitric acid.

 

Before I get back into the silvering with homebrew, I'm researching and listening to others who have done the basic formulas adapted to spray technique.  The old methods of an immersion bath is wasteful. My first mirror 1966, was silvered in a bath and I remember it using a lot of solution.

Edited by ccaissie, 25 March 2025 - 08:55 AM.

[hamishbarker]

90gm of silver nitrate will keep you going for a long time. When doing my 22 inch mirror I'm using about 5 grams or so for 350ml of silvering solution and the same volume of reducing ( glucose) solution in the two spray bottles. this usually provides sufficient that if the first attempt is obviously going away ( brown streaks or weak), I can stop and have enough to quickly strip, reclean and respray.

[ccaissie]

I do have questions on Tom Stock's description of his formula/method here in Post #9  

 

https://www.cloudyni.../?hl= silvering

 

Can I mix AgNO3 and water solution and keep it in the fridge?

 

Can I do the combination with NaOH & NH3OH to make up BOTTLE A and keep it in the fridge?

 

How does Angel Gilding make up the solution that keeps for years?  

 

I'll now try doing exactly the Tom Stock recipe...make the 3gram recipe and then try it over time.

 

I did buy two of the recommended pump spray bottles, as i also notice the irregular spray of the home depot squirt sprayers.

[hamishbarker]

Silver nitrate solution must be kept in the dark. I don't know how angel gilding solution manages to last. You could try wrapping your bottle in aluminium foil or use a brown glass reagent bottle.

As far as the second question, I assume you mean NaOH and NH4OH but without the silver nitrate? That might work.

Definitely no to storing the titrated, made up Tollens reagent. it is very unstable and breaks down under exposure to light, plus the risk of explosion if it manages to dry out ( perhaps above the liquid line?) and form silver azide or other explosive silver compound.

[careysub]

Silver nitrate solution must be kept in the dark. I don't know how angel gilding solution manages to last. You could try wrapping your bottle in aluminium foil or use a brown glass reagent bottle.

Or look in your grocery store for a product that comes in a cylindrical container of the correct size for your bottle -- container just needs to be opaque, metal or cardboard are both fine.