Re coating of the Shane three meter telescope mirror
in February, 2000.

Re-coating the 3 meter mirror at Lick Observatory.
in February, 2016.


Information on mirror de-coating:

We have been recommended to a mixture of

90 percent Phosphoric Acid
  5 percent HCl
  5 percent H2SO4 

For mirror de-coating. 

Also recommended Jasco Metal Enchant from Ace Hardware.

From Paul O.

More info

De-coating at Aluminum Coating
We use a multi step process,
cleaning, first with water followed by paint thinner and finally lacquer thinner.
Then a soak for two days with the mirror surface submerged in printed circuit board etchant.
Then soak overnight in diluted swimming pool acid.
All mirrors get a final cleaning with pure methanol before coating.

While rubbing with a soft abrasive such as talc might help remove
a stubborn coating we do not do that process here.
Polishing and figuring is left to other vendors.

Chrome Primer Coating, Yes or No

We recommend avoiding the use of Sodium Hydroxide, NaOH and
strong, concentrated acids.

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Page last edited July 7, 2020