Today I’m preparing to silver a mirror. I use the Rochelle salt method as follows:
Solution 1: Silver nitrate 2.48 grams, silver nitrate 2.07 grams, distilled water 473mls, 25% ammonia as required.
Dissolve 2.48 grams of silver nitrate in 120mls water stirring with a glass rod. Add around 30 drops of ammonia, the solution will go dark and will then gradually clear again. Once the solution is clear add the rest of the silver and swirl until dissolved. Add the remaining water. Leave to settle for an hour or two then filter and store in a dark bottle labelled Solution 1.
Solution 2: Rochelle salts (potassium sodium tartrate) 1.56 grams, silver nitrate 1.62 grams, distilled water 473mls.
Add 1.56g rochelle salts to water in a glass vessel and bring to the boil. After boiling for 1 minute add the silver nitrate and boil for a further 5 minutes. Leave to cool then filter and store in a dark glass bottle labelled Solution 2.
Thoroughly clean and de-grease the glass to be silvered and tape up any areas on which silvering is not required. Warm the glass to about 38C with warm distilled water, when warm, drain off the water and cover with a 1:1 mixture of solutions 1 and 2. It is best to warm the solutions before mixing them together. Swirl the mixture over the glass for around half an hour then pour off the solution, rinse in distilled water and leave to dry. Gently paint the back of the mirror with a suitable paint to protect it from abrasion.