Plaster priming

Copper sulfate

It is used to prime walls that are later painted with adhesive technology.
The gesso reduces the absorption of water into the plaster and protects it from microorganisms.
Such a gesso uses gray or green soap dissolved in water with the addition of glue to reduce the absorption of plaster.
Composition of copper sulfate gesso:

• 1 kg of soap,
• 1 kg of copper sulfate,
• 0.5 kg of glue,
• 2 ÷ 4 kg of lasered lime,
• 4 ÷ 6 buckets of water.

1 kg of soap is boiled in 3 ÷ 4 buckets and cooled.
In a water bath we heat the previously soaked glue and pour copper sulfate into it. We cool it down.
Into the cooled soap - stirring constantly - we pour the glue water with copper sulfate. If the liquid begins to thicken, we add milk of lime.
This gesso is blue-gray with a peculiar smell. It slightly stains the plaster, isolates the stains formed on the plaster, preserves the organic binder.
Before priming, the plaster should be dragged with lime milk.
Copper sulfate-free gesso can also be used.
Composition of gesso without copper sulfate:

• 1 kg of gray soap,
• 1/2 ÷ 3/4 of carpenter's glue,
• 4 buckets of water.

After boiling, the soap is mixed with the glue and diluted to the necessary density.
The ceiling is primed across the daylight and painted lengthwise.
Walls are primed horizontally, painted vertically.
A wall primed with soap and glue is no longer absorbent.
The primer is hot primed.