Fired Silver Paint: Silver Oxide and Flux in Purified Dextrin and Water (Gray, Erie Resistor 1954, Ex. 3)

A paint for putting silver electrodes on ceramic, glass or mica. Silver oxide and a little ceramic flux are held in purified dextrin dissolved in water. The wet paint conducts electricity, so a capacitor can be measured while it is being painted. On firing, the silver oxide turns into a silver film held on by the flux. Dextrin needs no alcohol against foam, and silver nitrate does not attack it while the paint is in use. Source: Robert B. Gray, US 2,695,275 (Erie Resistor, 1954), Example 3. Unknown: how the dextrin is purified. Gray does not give it. Also not given: which flux, and the firing heat. Bismuth subnitrate, one of the fluxes Gray names, is ours. Picture drawn by Youblob.

مبتدئ

1 day

التعليمات

Dissolve 4 g purified dextrin in the water

For 100 g of paint: dissolve 4 g purified dextrin in the water. The water is the balance, about 31 to 44 g. Unknown: how the dextrin is purified. Gray does not give it.

المواد لهذه الخطوة:

دكسترين منقّى4 غ

ماء مقطر1 as required

الأدوات المطلوبة:

ميزان ذو كفّتين

كأس زجاج بوروسيليكاتي

قضيب زجاج بوروسيليكاتي

Grind in silver oxide and flux

Grind 50 g precipitated silver oxide and 2 to 10 g ceramic flux into the solution until smooth. Gray gives the flux only as a class; ours: bismuth subnitrate, one of the common fluxes he names. The right amount depends on the ceramic it will be fired onto.

المواد لهذه الخطوة:

أكسيد الفضة50 غ

تحت نترات البزموت1 as required

الأدوات المطلوبة:

ميزان ذو كفّتين

هاون ومِدَقّ

قفازات نتريل

Stir in up to 5 g silver nitrate

Stir in 0 to 5 g silver nitrate; it makes the wet paint conduct better. Dextrin is not attacked by it in normal use, and the paint can stand for hours without stirring. Silver nitrate stains and burns skin: gloves.

المواد لهذه الخطوة: